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Purpose: To observe the variability in the plasma concentrations and pharmacokinetic-pharmacodynamic (PK-PD) profiles of first-line antitubercular drugs in pulmonary tuberculosis (TB) patients with and without diabetes mellitus (DM)., Methods: Newly diagnosed pulmonary TB patients aged 18-60 years with or without DM were included in the study. Group I (n = 20) included patients with TB, whereas group II (n = 20) included patients with both TB and DM. After 2 weeks of therapy, plasma concentrations and other PK-PD parameters were determined. Improvements in clinical features, X-ray findings, sputum conversion, and adverse drug reactions (ADRs) were assessed after 2 months of therapy., Results: Isoniazid displayed non-significantly higher plasma concentrations in diabetic patients, along with a significantly (P < 0.05) longer elimination half-life (t 1/2 ). Rifampicin plasma concentrations at 4, 8, and 12 h were significantly (P < 0.05) lower, and it displayed significantly (P < 0.05) lower area under the curve (AUC 0-12 and AUC 0-∞ ), shorter t 1/2 , higher clearance (Cl), and a lower AUC 0-∞ /MIC ratio in diabetic patients. Pyrazinamide and ethambutol showed non-significantly higher plasma concentrations, AUC 0-12 , AUC 0-∞ , and t 1/2 in diabetic patients. The improvements in clinical features, X-ray findings, sputum conversion, and ADRs were comparable in both groups., Conclusions: The presence of DM in TB patients affects the PK-PD parameters of isoniazid, rifampicin, pyrazinamide, and ethambutol variably in the Indian population. Studies with a larger number of patients are required to further elucidate the role of DM on the PK-PD profile of first-line antitubercular drugs and treatment outcomes in TB patients with concomitant DM., Trial Registration: CTRI/2021/08/035578 dated 11/08/2021., Competing Interests: Declarations Conflict of interest The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: Intestinal obstruction is a common complication in patients with advanced malignancies, often attributed to the disease itself or as a side effect of opioid analgesics used for pain management. However, the occurrence of intestinal obstruction following antituberculosis therapy is rare., Case Presentation: We report a unique case of a 58-year-old Asian male diagnosed with stage IV pancreatic carcinoma and pulmonary tuberculosis. The patient was initiated on a regimen of ethambutol hydrochloride, pyrazinamide, rifampicin, and isoniazid tablets (II) for tuberculosis, alongside morphine for the management of severe cancer-related pain. Subsequently, he developed symptoms indicative of intestinal obstruction. Despite discontinuation of morphine, the patient's symptoms persisted until he autonomously ceased all medications, leading to a rapid improvement in his condition. This unexpected resolution highlighted the antituberculosis drugs as the probable cause of his intestinal obstruction., Conclusions: This case underscores the importance of considering antituberculosis drugs as a potential cause of intestinal obstruction, especially in patients who do not respond to conventional management strategies for drug-induced gastrointestinal side effects. It also emphasizes the need for heightened vigilance and monitoring when prescribing these medications to patients with advanced malignancies, to promptly identify and address rare but significant side effects., (© 2024. The Author(s).)

Background and Objective: Pyrazinamide (PZA) is the standard first-line treatment for tuberculosis (TB); however, its safety in elderly patients has not been thoroughly investigated., Methods: This retrospective study used data from the Japanese Diagnosis Procedure Combination inpatient database. We identified patients who were admitted for TB between July 2010 and March 2022. Patients were categorized into HRE (isoniazid, rifampicin and ethambutol) and HREZ (isoniazid, rifampicin, ethambutol and PZA) groups. Primary outcomes included in-hospital mortality and overall adverse events (characterized by a composite of hepatotoxicity, gout attack, allergic reactions and gastrointestinal intolerance). Secondary outcomes included the length of hospital stay, 90-day readmission and use of drugs related to the primary outcome adverse events. Data were analysed using propensity score matching; we also conducted a subgroup analysis for those aged ≥75 years., Results: Among 19,930 eligible patients, 8924 received HRE and 11,006 received HREZ. Propensity score matching created 3578 matched pairs with a mean age of approximately 80 years. Compared with the HRE group, the HREZ group demonstrated a higher proportion of overall adverse events (3.1% vs. 4.7%; p < 0.001), allergic reactions (1.4% vs. 2.5%; p < 0.001) and antihistamine use (21.9% vs. 27.6%; p < 0.001). No significant differences were observed regarding in-hospital mortality, hepatotoxicity or length of hospital stay between the groups. Subgroup analysis for those aged ≥75 years showed consistent results., Conclusion: Medical practitioners may consider adding PZA to an initial treatment regimen even in elderly patients with TB., (© 2024 The Author(s). Respirology published by John Wiley & Sons Australia, Ltd on behalf of Asian Pacific Society of Respirology.)

Background: Tuberculosis (TB) lymphadenitis is the most common form of extra-pulmonary TB, and the treatment duration is six months. This non-inferiority based randomized clinical trial in South India evaluated the efficacy and safety of a four-month ofloxacin containing regimen in tuberculosis lymphadenitis (TBL) patients., Methods: New, adult, HIV-negative, microbiologically and or histopathologically confirmed superficial lymph node TB patients were randomized to either four-month oflaxacin containing test regimen [ofloxacin (O), isoniazid (H), rifampicin (R), pyrazinamide (Z) -2RHZO daily/ 2RHO thrice-weekly] or a six-month thrice-weekly control regimen (2HRZ, ethambutol/4RH). The treatment was directly observed. Clinical progress was monitored monthly during and up to 12 months post-treatment, and thereafter every three months up to 24 months. The primary outcome was determined by response at the end of treatment and TB recurrence during the 24 months post-treatment., Results: Of the 302 patients randomized, 298 (98.7%) were eligible for modified intention-to-treat (ITT) analysis and 294 (97%) for per-protocol (PP) analysis. The TB recurrence-free favourable response in the PP analysis was 94.0% (95% CI: 90.1-97.8) and 94.5% (95% CI: 90.8-98.2) in the test and control regimen respectively, while in the ITT analysis, it was 92.7% and 93.2%. The TB recurrence-free favourable response in the test regimen was non-inferior to the control regimen 0.5% (95% CI: -4.8-5.9) in the PP analysis based on the 6% non-inferiority margin. Treatment was modified for drug toxicity in two patients in the test regimen, while one patient had a paradoxical reaction., Conclusion: The 4-month ofloxacin containing regimen was found to be non-inferior and as safe as the 6-month thrice-weekly control regimen., (© 2024. The Author(s).)

Background: Results of retrospective studies have suggested clofazimine as an alternative for rifampicin in the treatment of Mycobacterium avium complex pulmonary disease (MAC-PD)., Research Question: Is a treatment regimen consisting of clofazimine-ethambutol-macrolide noninferior to the standard treatment regimen (rifampicin-ethambutol-macrolide) in the treatment of MAC-PD?, Study Design and Methods: In this single-center, nonanonymized clinical trial, adult patients with MAC-PD were randomly assigned in a 1:1 ratio to receive rifampicin or clofazimine as adjuncts to an ethambutol-macrolide regimen. The primary outcome was sputum culture conversion following 6 months of treatment., Results: Forty patients were assigned to receive either rifampicin (n = 19) or clofazimine (n = 21) in addition to ethambutol and a macrolide. Following 6 months of treatment, both arms showed similar percentages of sputum culture conversion based on an intention-to-treat analysis: 58% (11 of 19) for rifampicin and 62% (13 of 21) for clofazimine. Study discontinuation, mainly due to adverse events, was equal in both arms (26% vs 33%). Based on an on-treatment analysis, sputum culture conversion following 6 months of treatment was 79% in both groups. In the clofazimine arm, diarrhea was more prevalent (76% vs 37%; P = .012), while arthralgia was more frequent in the rifampicin arm (37% vs 5%; P = .011). No difference in the frequency of corrected QT interval prolongation was seen between groups., Interpretation: A clofazimine-ethambutol-macrolide regimen showed similar results to the standard rifampicin-ethambutol-macrolide regimen and should be considered in the treatment of MAC-PD. The frequency of adverse events was similar in both arms, but their nature was different. Individual patient characteristics and possible drug-drug interactions should be taken into consideration when choosing an antibiotic regimen for MAC-PD., Clinical Trial Registration: EudraCT; No.: 2015-003786-28; URL: https://eudract.ema.europa.eu., Competing Interests: Financial/Nonfinancial Disclosures The authors have reported to CHEST the following: B. G. has a relationship with AbbVie and Bionano Genomics. J. v. I. is an advisory board member for Paratek, AN2, Insmed, MannKind, and Janssen. W. H. has received a Stichting Management Apothekers en de Gezondheidszorg (Stimag) Grant for an investigator-initiated trial (“Pharmacokinetic study of minocycline in patients with pulmonary nontuberculous mycobacterial disease”). S. M. H. Z. reports funding as stated for this article. None declared: (M. J. B., R. A., R. S., C. M.-E.)., (Copyright © 2024. Published by Elsevier Inc.)

Purpose: We aimed to investigate the visual recovery time in patients with ethambutol-induced toxic optic neuropathy (EON) and identify the factors associated with the visual recovery time., Methods: In this retrospective cohort study, we reviewed the medical records of 35 eyes from 35 patients with EON. Visual recovery was defined as a gain of three or more lines from the nadir., Results: Patients were observed following discontinuation of ethambutol (EMB), with the mean follow-up period of 21.0 ± 16.0 months. The visual acuity at nadir was logarithm of the minimum angle of resolution 1.4 ± 0.4, and the final visual acuity was logarithm of the minimum angle of resolution 0.6 ± 0.5. Twenty-seven eyes (77.1%) showed significant visual recovery. In Kaplan-Meier survival, the mean estimated time for visual recovery was 15.2 ± 3.0 months, and 50% of the patients experienced visual recovery at 8.3 ± 2.2 months following EMB discontinuation. Multivariate Cox regression analysis identified several significant risk factors for delayed visual recovery, including duration of EMB medication ≤6 months, period from symptom onset to EMB discontinuation &gt;14 days, and baseline peripapillary retinal nerve fiber layer thickness &gt;98 μm., Conclusions: Our study indicated a mean time of visual recovery of 15 months for EON cases. Therefore, patients diagnosed with EON should be followed up for more than 1 to 2 years to evaluate their visual recovery. Delayed EMB discontinuation, short duration of EMB use, and initial peripapillary retinal nerve fiber layer thickening were associated with delayed visual recovery. Therefore, patients taking EMB should be followed up regularly for early detection of EON and immediate discontinuation of EMB to prevent severe damage to the optic nerve.

Objectives: The research aimed to study the following questions: (1) five well-known gout-related medications were selected to test the validity of the prescription symmetry sequence analysis in Taiwan; (2) four exploratory medications were selected to test their relation to gout flares., Methods: We utilized the 2003-2017 dataset of the Taiwan National Health Insurance Program containing all claims data with 2 million beneficiaries as a data source. In order to explore the temporal association, we designed a scenario of medication-induced gout flares. Nine medications were selected as the index agent, including aspirin (low-dose), thiazide diuretics, loop diuretics, ethambutol, pyrazinamide, metformin, pioglitazone, fenofibrate, and losartan. The gout flare was defined as subjects with use of the marker agent for treatment of gout flares. The observation-window period between initiation of the index agent and initiation of the marker agent was 1 year. Subjects who used an index agent and a marker agent on the same day were excluded. The prescription symmetry sequence analysis was carried out to compare the observed number of persons who took an index agent prior to starting a marker agent with the observed number of persons who took a marker agent before starting an index agent. The adjusted sequence ratio (adjusted SR) with 95% confidence interval was applied to estimate the relation between an index agent and the marker agent., Results: Among five medications including aspirin (low-dose), thiazide diuretics, loop diuretics, ethambutol, and pyrazinamide, the adjusted sequence ratio ranged from 1.15 to 3.35 and all reached statistical significance. Fenofibrate use and losartan use were associated with a lower probability of gout flares, with reaching statistical significance (adjusted SR = 0.60 for fenofibrate and adjusted SR = 0.92 for losartan). Metformin use was associated with a greater probability of gout flares, with reaching statistical significance (adjusted SR = 1.14). Pioglitazone use did not reach statistical significance., Conclusion: Based on the confirmatory analysis including five well-known gout-related medications, this study supports that the prescription symmetry sequence analysis can be used to detect an adverse drug event associated with one potential offending agent. The exposure to fenofibrate or losartan might be a protective factor against gout flares. Metformin use could be associated with a greater probability of gout flares, but this finding should be validated by other studies., Key Points: • What is already known about this subject? 1. The prescription symmetry sequence analysis is a useful method for detecting an adverse drug reaction associated with one potential offending drug. 2. Numerous medications are found to induce gout flares. • What does this study add? 1. The prescription symmetry sequence analysis supports the evidence that aspirin (low-dose), thiazide diuretics, loop diuretics, ethambutol and pyrazinamide are associated with a greater probability of gout flares. 2. The exposure to fenofibrate or losartan might be a protective factor against gout flares. 3. Metformin use could be associated with a greater probability of gout flares. • How might this impact on clinical practice or future developments? 1. Clinicians should always consider the possibility of medication-induced gout flares. If gout flares develop, discontinuation of risky medications is the first step. Then prescribing cascades can be eliminated., (© 2024. The Author(s), under exclusive licence to International League of Associations for Rheumatology (ILAR).)

Objectives: To assess the efficacy and safety of rifampicin-based triple therapy (rifampicin, isoniazid, and ethambutol) for treating NPM., Methods: This single-center, single-arm, prospective clinical trial was conducted at the Second Hospital of Shandong University (Jinan, China). Patients with pathologically diagnosed granulomatous lobular mastitis and periductal mastitis received triple drugs, i.e., rifampicin (450 mg/day), isoniazid (300 mg/day), and ethambutol (15 mg/kg/day), until complete response or the investigator decided to discontinue treatment. The primary endpoint was the complete response rate (CRR) assessed by the investigator. The secondary endpoints included the overall remission rate (ORR), recurrence rate (RR), and safety., Results: A total of 218 patients were enrolled in the study between January 1, 2013 and October 31, 2020. With a median follow-up time of 48 months, the CRR and the ORR were 78.44% and 94.04%, respectively. While 13 patients (5.96%) demonstrated no response and 19 relapsed (8.72%). Adverse events (AEs) were not common. The most common AEs during treatment were liver dysfunction (1.83%), gastrointestinal reactions (1.83%), fatigue (1.83%), erythema (1.38%), and menstrual disorders (0.92%)., Conclusion: Rifampicin, isoniazid, and ethambutol demonstrated promising response rates with acceptable safety profiles in patients with NPM. Further confirmatory trial is warranted in the future., Trial Registration: The study was approved by the Ethics Committee of the Second Hospital of Shandong University and retrospectively registered at the China Clinical Trial Registration Center (registration number: ChiCTR2100049591)., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Standard treatment for tuberculosis (TB) in children and adults includes an initial two-month course of ethambutol, a drug that in rare cases can cause optic neuropathy and irreversible vision loss. There is a lack of clear guidance on what vision assessments are needed before and during treatment with ethambutol, with the Royal College of Ophthalmologists, National Institute for Health and Care Excellence, British National Formulary and British Thoracic Society offering different guidance. We aimed to assess how vision is routinely tested in patients treated with ethambutol in TB services across England., Methods: An online survey developed by Public Health England was sent to all TB services in England in 2018 to assess current practice and inform the development of best practice recommendations for visual assessment of patients treated with ethambutol for TB., Results: Sixty-six TB professionals from across England responded, a response rate of 54%. The results showed variations in practice, including when to omit ethambutol from treatment, the timing and frequency of visual assessment, the type of visual assessment, referral processes and management of visual changes., Conclusion: This national survey highlights the need for clear guidelines on the testing of vision for patients taking ethambutol at recommended doses, before and during treatment. We suggest a pragmatic approach to visual assessment to reduce variation in practice, proposing a stepwise pathway for patients on standard TB treatment for local adaptation., (© 2023. The Author(s).)

Aim: To screen patients on ethambutol and evaluate its role on visual functions and toxic optic neuropathy., Setting and Design: Retrospective, observational single tertiary centre cohort of 80 patients., Methods and Material: A total of 69 from the initial 80 patients with visual complaints were categorised into two groups A and B; ongoing anti-tubercular therapy with ethambutol and having stopped ethambutol for greater than six months respectively. All patients underwent vision (V) testing on ETDRS chart and anterior and posterior segment evaluation. Additionally, patients in group A recorded color vision (CV) on Ishihara chart and visual evoked potential (VEP)., Statistical Analysis Used: P value was calculated using Chi square test (SPSS ver. 20)., Results: Out of 69 patients in our study, 58 (84.05%) patients recorded reduced visual acuity. The mean visual acuity was 0.58 logMAR units. 33 out of our 58 (57%) patients with reduced visual acuity showed normal optic discs while 25 out of 58 (43%) showed altered optic discs. In group B, 14 out of 32 patients with vision of less than 20/20 also had optic disc pallor (p = 0.02). 12 out of 15 patients in group A recorded an altered color vision and also had a vision of less than 20/20 (p = 0.023). 15 patients who recorded altered VEP also had vision of less than 20/20 (p = 0.037)., Conclusion: Visual acuity, color vision and vep are sensitive and sustainable tools which can be implemented in regular screening. Ethambutol toxicity is a real problem and a collaborative approach is necessary to establish screening protocols and prevent ethambutol induced toxic optic neuropathy., Competing Interests: Conflicts of interest The authors have none to declare., (Copyright © 2023 Tuberculosis Association of India. Published by Elsevier B.V. All rights reserved.)

Ethambutol is an antibiotic widely used for treatment of Mycobacterium species. Although it is safe to use in patients, the ocular toxic impact, including optic neuropathy and retinopathy, can be observed in patients using ethambutol. After discontinuation of the drug, the ocular toxic effects can be reversible in some patients, but some are not. Ethambutol-induced optic neuropathy has been recognized for more than six decades and the prevalence of optic neuropathy from a standard dose of ethambutol has been reported as 0.7-1.29%. Several factors associated with ethambutol-induced optic neuropathy include dosage/duration of drug, the medical conditions of patients such as renal and hepatic dysfunction and preexisting mitochondrial mutations. Currently, there is no specific treatment and prevention of ethambutol-induced optic neuropathy. In addition, the potential underlying mechanisms of ethambutol-induced optic neuropathy is still unclear. Therefore, this review aimed to summarize and discuss evidence from clinical, in vitro, and in vivo studies in order to explore the potential pathophysiology of ethambutol-induced optic neuropathy. Any contradictory findings are also included and discussed. The insights gained from the review will facilitate the discovery of novel approaches for prevention and treatment of optic neuropathy-induced by ethambutol., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Physiological changes during pregnancy may alter the pharmacokinetics (PK) of antituberculosis drugs. The International Maternal Pediatric Adolescent AIDS Clinical Trials Network P1026s was a multicenter, phase IV, observational, prospective PK and safety study of antiretroviral and antituberculosis drugs administered as part of clinical care in pregnant persons living with and without HIV. We assessed the effects of pregnancy on rifampin, isoniazid, ethambutol, and pyrazinamide PK in pregnant and postpartum (PP) persons without HIV treated for drug-susceptible tuberculosis disease. Daily antituberculosis treatment was prescribed following World Health Organization-recommended weight-band dosing guidelines. Steady-state 12-hour PK profiles of rifampin, isoniazid, ethambutol, and pyrazinamide were performed during second trimester (2T), third trimester (3T), and 2-8 of weeks PP. PK parameters were characterized using noncompartmental analysis, and comparisons were made using geometric mean ratios (GMRs) with 90% confidence intervals (CI). Twenty-seven participants were included: 11 African, 9 Asian, 3 Hispanic, and 4 mixed descent. PK data were available for 17, 21, and 14 participants in 2T, 3T, and PP, respectively. Rifampin and pyrazinamide AUC 0-24 and C max in pregnancy were comparable to PP with the GMR between 0.80 and 1.25. Compared to PP, isoniazid AUC 0-24 was 25% lower and C max was 23% lower in 3T. Ethambutol AUC 0-24 was 39% lower in 3T but limited by a low PP sample size. In summary, isoniazid and ethambutol concentrations were lower during pregnancy compared to PP concentrations, while rifampin and pyrazinamide concentrations were similar. However, the median AUC 0-24 for rifampin, isoniazid, and pyrazinamide met the therapeutic targets. The clinical impact of lower isoniazid and ethambutol exposure during pregnancy needs to be determined., Competing Interests: The authors declare no conflict of interest.

Introduction: Drug-induced thrombocytopenia is a known adverse event of several drugs. Antitubercular therapy (ATT) is rarely reported but important cause of thrombocytopenia. The present review aimed to understand the profile of thrombocytopenia caused by first-line ATT i.e. isoniazid, rifampicin, pyrazinamide, and ethambutol., Materials and Methods: We screened case reports, case series, and letter-to-editor from databases, like Pubmed/MEDLINE, Ovid, and EMBASE from 1970 to 2021. The PRISMA guidelines were followed in the present systematic review., Results: Categorical data were expressed as n (%) and quantitative data were expressed as median (IQR). After applying the inclusion/exclusion criteria, 17 case reports and 7 letters to the editor were selected for the present review. Rifampicin was most frequently associated with thrombocytopenia (65%). A median (IQR) drop to 20,000 (49,500) platelets/mm3 was observed. Anti-rifampicin associated antibodies and anti-dsDNA positivity were found in six studies. Except for two, all patients responded to symptomatic treatment., Discussion: ATT-induced thrombocytopenia can be life-threatening and require hospitalization. Clinicians should be aware of the association of ATT with thrombocytopenia and should take appropriate measures for patient management., Conclusion: This review provides clinicians a comprehensive picture of adverse effects and their management in ATT induced thrombocytopenia., Competing Interests: Conflicts of interest The authors have none to declare., (Copyright © 2023 Tuberculosis Association of India. Published by Elsevier B.V. All rights reserved.)

Rifampicin is an important agent for tuberculosis treatment; however, it is often discontinued because of adverse reactions. The treatment regimen then can be administered as that for rifampicin-resistant tuberculosis, which can be toxic. We retrospectively reviewed 114 patients with drug-susceptible pulmonary tuberculosis who discontinued rifampicin due to adverse reactions during an 18 year period at a tertiary referral center, of which 92 (80.7%) exhibited favorable response. Hepatotoxicity was the leading cause of intolerance. Patients with a favorable response were younger and less likely to have comorbidities. The majority of patients were administered four medications during the intensive phase and three to four during the consolidative phase. For those with a favorable response, the median duration of treatment was 10.2 months and the most common intensive regimen was a combination of isoniazid, ethambutol, pyrazinamide, and fluoroquinolone (25%). The most common consolidation regimen was a combination of isoniazid, ethambutol, and fluoroquinolone (22.8%). Among the patients with a favorable response, two (2.2%) experienced recurrence after a follow-up of 3.4 (interquartile range 1.8-6.8) years. For patients with drug-susceptible pulmonary tuberculosis who do not tolerate rifampicin owing to its toxicity, a shorter regimen may be a useful alternative., (© 2023. The Author(s).)

Introduction: Toxic optic neuropathy is a severe optic nerve injury that can compromise the prognosis for vision, justifying early clinical and ancillary diagnosis., Case Description: We report the case of an 11-year-old child being treated for tuberculous meningitis with a combination of ethambutol and three other anti-bacillary drugs, referred for a rapidly progressive bilateral decline in visual acuity. On ophthalmologic examination, the visual acuity was counting fingers within 1ft in both eyes, and bilateral optic disc pallor was noted, without other associated abnormalities. Neurological imaging was unremarkable, with red-green dyschromatopsia and a bilateral cecocentral scotoma. Faced with this clinical and paraclinical picture, we arrived at the diagnosis of ethambutol toxic optic neuropathy, with a multidisciplinary decision leading to a change in the antibacillary treatment protocol. No clinical improvement was noted after 3 months of follow-up., Discussion: Optic nerve toxicity is rare in children and is classically described as dose- and time-dependent., Conclusion: Ethambutol ocular toxicity is extremely rare in children, and the required action when detected is to discontinue the drug. Reversibility is not always assured, which requires early detection of toxic optic neuropathy by close clinical and ancillary monitoring and, above all, sensitization of the treating physicians (pediatricians, pulmonologists and neurologists)., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

Background: Tuberculosis is usually treated with a 6-month rifampin-based regimen. Whether a strategy involving shorter initial treatment may lead to similar outcomes is unclear., Methods: In this adaptive, open-label, noninferiority trial, we randomly assigned participants with rifampin-susceptible pulmonary tuberculosis to undergo either standard treatment (rifampin and isoniazid for 24 weeks with pyrazinamide and ethambutol for the first 8 weeks) or a strategy involving initial treatment with an 8-week regimen, extended treatment for persistent clinical disease, monitoring after treatment, and retreatment for relapse. There were four strategy groups with different initial regimens; noninferiority was assessed in the two strategy groups with complete enrollment, which had initial regimens of high-dose rifampin-linezolid and bedaquiline-linezolid (each with isoniazid, pyrazinamide, and ethambutol). The primary outcome was a composite of death, ongoing treatment, or active disease at week 96. The noninferiority margin was 12 percentage points., Results: Of the 674 participants in the intention-to-treat population, 4 (0.6%) withdrew consent or were lost to follow-up. A primary-outcome event occurred in 7 of the 181 participants (3.9%) in the standard-treatment group, as compared with 21 of the 184 participants (11.4%) in the strategy group with an initial rifampin-linezolid regimen (adjusted difference, 7.4 percentage points; 97.5% confidence interval [CI], 1.7 to 13.2; noninferiority not met) and 11 of the 189 participants (5.8%) in the strategy group with an initial bedaquiline-linezolid regimen (adjusted difference, 0.8 percentage points; 97.5% CI, -3.4 to 5.1; noninferiority met). The mean total duration of treatment was 180 days in the standard-treatment group, 106 days in the rifampin-linezolid strategy group, and 85 days in the bedaquiline-linezolid strategy group. The incidences of grade 3 or 4 adverse events and serious adverse events were similar in the three groups., Conclusions: A strategy involving initial treatment with an 8-week bedaquiline-linezolid regimen was noninferior to standard treatment for tuberculosis with respect to clinical outcomes. The strategy was associated with a shorter total duration of treatment and with no evident safety concerns. (Funded by the Singapore National Medical Research Council and others; TRUNCATE-TB ClinicalTrials.gov number, NCT03474198.)., (Copyright © 2023 Massachusetts Medical Society.)

A hyperuricemic rat model induced by adenine and ethambutol was established to investigate the anti-hyperuricemia activity and its mechanism of the flavonoid extract from saffron floral bio-residues. Sixty-seven SD rats were randomly divided into control group, model group, positive control group, and flavonoid extract groups(with 3 doses), respectively, and each group contained 11 or 12 rats. The hyperuricemic model was established by continuous oral administration of adenine(100 mg·kg~(-1)) and ethambutol(250 mg·kg~(-1)) for 7 days. At the same time, the positive control group was given allopurinol(20 mg·kg~(-1) per day) and the flavonoid extract groups were given the flavonoid extract at doses of 340, 170 and 85 mg·kg~(-1) per day, respectively. On day 8, rat serum, liver, kidney, and intestinal tissues were collected, and the levels of uric acid in serum and tissue, the xanthine oxidase activities and antioxi-dant activities in serum and liver were evaluated, and the kidney histopathology was explored. In addition, an untargeted serum metabolomics study was performed. According to the results, the flavonoid extract effectively reduced the uric acid levels in serum, kidney and ileum and inhibited the xanthine oxidase activities and elevated the antioxidant activities of serum and liver in hyperuricemic rat. At the same time, it reduced the levels of inflammation factors in kidney and protected renal function. Moreover, 68 differential metabolites of hyperuricemic rats were screened and most of which were lipids and amino acids. The flavonoid extract significantly retrieved the levels of differential metabolites in hyperuricemic rats, such as SM(d18:1/20:0), PC[18:0/18:2(92,12Z)], palmitic acid and citrulline, possibly through the following three pathways, i.e., arginine biosynthesis, glycine, serine and threonine metabolism, and histidine metabolism. To sum up, the flavonoid extract of saffron floral bio-residues lowered the uric acid level, increased the antioxidant activity, and alleviated inflammatory symptoms of hyperuricemic rats, which may be related to its inhibition of xanthine oxidase activity and regulation of serum lipids and amino acids metabolism.

Objective: The study was conducted to evaluate the ocular toxicity of ethambutol given in both intensive and continuation phases of treatment in children with drug-sensitive tuberculosis., Methods: A prospective study of 94 eyes from 47 patients receiving an ethambutol-containing regimen was conducted between 1 December, 2018 and 31 August, 2020. Visual acuity, visual field, visual evoked response (VER), contrast sensitivity, colour perception, and retinal nerve fiber layer (RNFL) thickness [using optical coherence tomography (OCT)] were tested for each patient before, during, and after the treatment., Results: On follow-up, visual acuity, color vision, contrast sensitivity, fundus, and visual fields were not affected in any of the patients. There was no statistically significant increase in the mean latency of the P(100) wave at any point in time. On OCT, no significant loss of mean RNFL thickness was detected., Conclusions: Ethambutol is safe to use up to a dose of 20 mg/kg/day throughout the entire course of anti-tubercular therapy in children with drug-sensitive tuberculosis.

Rationale: Drug induced liver injury (DILI) is a common side effect causing treatment discontinuation during tuberculosis (TB) treatment, and pyrazinamide (PZA) usually leads to a delayed and prolonged abnormal liver function of the 4 standard anti-tuberculosis regimens. However, a prolonged hepatitis lasting more than 4 months is rarely reported., Patient Concerns: A 78-year-old man presented with general weakness and poor appetite on his seventh week of anti-TB treatment for tuberculosis lymphadenitis., Diagnosis: Drug induced liver injury, PZA-related. NAT2 slow acetylator phenotype was accidentally found during workup of DILI., Intervention: A liver biopsy was performed and PZA-related DILI was suspected. All anti-TB medications were therefore discontinued., Outcome: After withholding all anti-TB medications for 4 months, the elevations of aminotransferases and hyperbilirubinemia completely resolved. Anti-TB therapy was switched to ethambutol and levofloxacin for 15 months without adverse events. Long-term ultrasound follow-up was performed and cervical lymphadenopathy completely resolved., Conclusion: Our patient presents with PZA related prolonged DILI resolved after drug discontinuation for 4 months. NAT2 slow acetylator phenotype may be related to this condition through unknown mechanisms., Competing Interests: The authors have no conflict of interest to disclose., (Copyright © 2022 the Author(s). Published by Wolters Kluwer Health, Inc.)

Backgroud: Ethambutol hydrochloride (EMB) is used in the treatment of tuberculosis and is used as first line modality in combination with other medications. Ethambutol optic neuropathy (EON) is a rare but well-recognised adverse ocular event in patients who receive ethambutol for the treatment of mycobacterial infections and may be potentially devastating with reversible to irreversible changes in visual acuity., Key Findings: Optical coherence tomography has been used to evaluate the thickness of retinal nerve fibre and ganglion cell layers to look for degenerative changes and early markers. Electrophysiological tests like multifocal electroretinogram, visual evoked potentials and visual fields have been used to understand the functional changes associated with established EON and also whether these can be used to detect subclinical EON and correlate them with the structural changes. In this review, we have summarised evidence published till December 2021 related to evaluation of structural and functional changes in the retina and optic nerve in eyes with EON.

Purpose: To describe the increase in prevalence of ethambutol-induced optic neuropathy (EON) in patients presenting to a single tertiary referral eye care center in India after introduction of weight-based fixed dose combinations and an increase in duration of ethambutol use from 2016 in the Revised National Tuberculosis Control Program., Methods: This was a retrospective, observational, referral hospital-based study of 156 patients with a diagnosis of EON presenting to a single tertiary referral eye care center between January 2016 and December 2019. The main outcome measure was to assess the increase in prevalence of EON cases presenting to our tertiary care institute., Results: During the 4-year study period, 156 new patients were diagnosed with EON. A total of 101 patients (64.7%) were males and 55 (35.3%) were females. The most common age group affected was 41-60 years. The significant complaint at presentation was decreased vision in all the patients. A rising trend in the number of patients diagnosed as EON was seen, with the prevalence increasing from 16 cases in 2016, 13 cases in 2017, and 31 cases in 2018 to 96 cases in 2019., Conclusion: The results of this study indicated an alarming increase in the trend of EON cases presenting to our tertiary care institute., Competing Interests: None

Introduction: Tuberculosis remains a major public health problem in Nepal and anti-tubercular drugs used for the treatment of pulmonary and extrapulmonary tuberculosis can be associated with ocular toxicity. This prospective study aimed to evaluate the incidence of ocular toxicity among patients receiving anti-tubercular therapy and to assess the change in visual functions and ocular imaging before and after use of anti-tubercular therapy., Materials and Methods: A total of 89 eyes of 45 TB patients taking anti-tubercular therapy were enrolled. Detailed history and examination including best-corrected visual acuity (BCVA), colour vision (Farnsworth D-15t), contrast sensitivity (Pelli-Robson chart), Goldman visual field analysis and spectral domain optical coherence tomography for retinal nerve fibre layer (RNFL) analysis were assessed at baseline and at 6 months after starting anti-tubercular therapy. Visual evoked potential (VEP) was performed in suspected cases., Results: The mean age of the patients was 29.13±14.00 years and 62.2% were males. The mean weight of the subjects was 54.37±10.36 kg, mean daily dosage of ethambutol was 17.91±1.74 mg/day/kg and mean administration duration was 2.71±1.54 months. The incidence of ocular toxicity was 2.24%. Bilateral retrobulbar optic neuropathy occurred in a 27-year female of 55 kg receiving ethambutol (20 mg/kg/day) for 6 months for Pott's spine. Her best-corrected visual acuity in both eyes was reduced to 6/36 from 6/6 and developed non-specific color vision defect, decreased contrast sensitivity, bilateral cecocentral visual field defect and mean decrease in retinal nerve fibre layer thickness compared to the baseline data. In rest cases, a statistically significant decrease in mean retinal nerve fibre layer thickness in both eyes suggested the evidence of subclinical toxicity., Conclusion: Though less common, ethambutol toxicity can occur in patients under anti-tubercular therapy in the form of retrobulbar optic neuritis. Decreased contrast sensitivity and thinning in the mean retinal nerve fibre layer thickness can be the indicator of subclinical toxicity., (© NEPjOPH.)

Competing Interests: None

Competing Interests: None

Introduction: Ethambutol is an antibiotic used as a first line drug in the treatment of tuberculosis and a vision threatening side effect of EMB is ethambutol-induced optic neuropathy (EON). The aim of the study is to create awareness about the potentiality of ethambutol to cause ethambutol-induced optic neuropathy, careful monitoring of dose and patient education., Materials and Methods: A retrospective observational study of 14 patients whose complete Anti- tubercular treatment records could be retrieved were included. Epidemiological data including age, sex, systemic illness were recorded. Duration between optic nerve toxicity , usage of ethambutol and the drug dosage were noted. Best corrected visual acuity, anterior segment examination including pupils, extraocular movements, colour vision, central fields and fundus examination were evaluated. The patients were followed up at one and three month intervals., Results: Associated systemic illness was found to be a confounding factor for the development of ethambutol-induced optic neuropathy. 57% of patients had diabetes mellitus followed by hypertension (14.2%), renal disease (7.1%). The average daily dose of Ethambutol ingested was 1078.5 mg (21 mg/kg) and this high dose could have been the primary cause for development of ethambutol-induced optic neuropathy. Vision ranged from total blindness to mild visual impairment and poor recovery of vision was noted even after discontinuing ethambutol., Conclusion: Only a minority of patients showed improvement in visual function following discontinuation of ethambutol and the toxicity was found to be dose-dependent. Patients with comorbidities like renal impairment and diabetes mellitus appeared to be at greater risk. Ophthalmological examination before commencing treatment and periodic evaluation thereafter is mandatory., (© NEPjOPH.)

Background: In Japan, Mycobacterium avium complex lung disease (MAC-LD) is the most common in nontuberculous mycobacterial lung disease. Patients often experience adverse events, resulting in the discontinuation of treatment, which causes treatment failure. The JADER (Japanese Adverse Drug Event Report) database is a database of adverse events that allows us to collect real-world data on adverse events. We can collect large-scale data cost-effectively and detect signals of potential adverse events such as reporting odds ratio (ROR) by using spontaneous reporting systems. In this study, we aimed to elucidate the adverse events of clarithromycin (CAM), ethambutol (EB), and rifampicin (RFP) using the JADER database., Methods: We included cases of MAC-LD between April 2004 and June 2017. We investigated sex, age, and medications that may have caused the adverse events, outcomes, and time of onset. We calculated the safety signal index as the ROR. Time-to-event analysis was performed using the Weibull distribution., Results: The total number of adverse events of CAM, EB, and RFP was 2780, with 806 patients. In the overall adverse events, hematologic and lymphatic disorders were the most common adverse events, with 17.3%, followed by eye disorders (16.6%), and hepatobiliary disorders (14.0%). The outcomes were as follows: recovery, 40.0%; remission, 27.1%; non-recovery, 11.2%; and death, 7.1%. Regarding the most common onset time of CAM, EB, and RFP was within 120 days at 40%, 181-300 days at 43.6%, and within 120 days at 88.5%. For CAM, the RORs of infections and infestations, hepatobiliary system disorders, and immune system disorders were 4.13 (95% confidence interval [CI], 2.3-7.44), 2.61 (95% CI, 1.39-4.91), and 2.38 (95% CI, 1.04-5.44). For EB, the ROR of eye disorders was 215.79 (95% CI, 132.62-351.12). For RFP, the RORs of renal and urinary tract disorders and investigations were 7.03 (95% CI, 3.35-14.77) and 6.99 (95% CI, 3.22-15.18). The β value of EB was 2.07 (95% CI, 1.48-2.76), which was classified as a wear-out failure type., Conclusions: For MAC-LD, the adverse event which has the highest ROR is infections and infestations in CAM, eye disorders in EB, renal and urinary tract disorders in RFP. Adverse events of EB occur after 180 days, whereas the adverse events of CAM and RFP occur early in the course of treatment., (© 2022. The Author(s).)

While treatment of pulmonary infections by Mycobacterium tuberculosis is currently only rarely the cause of iatrogenic complications, treatment of atypical mycobacterial infections often requires prolonged treatment duration, which can lead to toxic optic neuropathies. This review summarizes the indications for such prolonged treatment and risk factors for toxic optic neuropathies when using ethambutol, isoniazid and/or linezolid and proposes customized screening recommendations., (Copyright © 2021 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Aim: To investigate the changes in macular vessel density (mVD) and its relationship to macular ganglion cell-inner plexiform layer (mGCIPL) thickness in patients receiving ethambutol (EMB) therapy for tuberculosis without recognisable clinical symptoms or signs of EMB-induced optic neuropathy (EON)., Methods: A total of 23 eyes of 13 patients using EMB therapy for 6 months without EON (preclinical EON) as the EMB group, 40 eyes of 23 healthy individuals as the normal control group and 18 eyes of 10 patients with tuberculosis before receiving EMB therapy as the blank control group were retrospectively analysed. The mean peripapillary retinal nerve fibre layer (pRNFL) and mGCIPL thicknesses and mVD were measured using optical coherence tomography angiography. Patients in the EMB group were compared with individuals in the normal and blank control groups, and changes in macular parameters were evaluated., Results: Central circle mVD (cCVD) was significantly lower in the EMB group than in both control groups (generalised estimating equation (GEE), p=0.003 and 0.029, respectively). The mGCIPL thickness in all regions and the mean pRNFL thickness were not significantly different between the EMB group and both control groups (GEE, p=1.000 for all). There were no significant differences in mVD, mGCIPL thickness and mean pRNFL thickness between the normal control and blank control groups (p>0.05). In the generalised linear model analyses, the minimum and inferonasal mGCIPL thicknesses were positively correlated with cCVD in the EMB group (β=1.285, p=0.003 and β=0.770, p=0.024, respectively)., Conclusions: cCVD decreased with no changes in mGCIPL and mean pRNFL thicknesses in patients with preclinical EON. The minimum and inferonasal mGCIPL thicknesses were positively correlated with cCVD. cCVD might be an early indicator for monitoring early-stage EMB toxicity., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Ethambutol use may lead to permanent vision loss by inducing a dose- and duration-dependent optic neuropathy. This has been of concern to ophthalmologists and physicians both; however, ethambutol continues to be used because of its anti-mycobacterial action with relative systemic safety. Recently, the guidelines of the Revised National Tuberculosis Control Programme of India have been revised to allow for fixed dose and longer duration of ethambutol use; this is likely to result in an increase in vision-threatening adverse effects. Taking cognizance of this, neuro-ophthalmologists, infectious disease specialists, and scientists met under the aegis of the Indian Neuro-Ophthalmology Society to deliberate on prevention, early diagnosis, and management of ethambutol-related toxic optic neuropathy. The recommendations made by the expert group focus on early suspicion of ethambutol toxicity through screening at the physician's office and opportunistic screening by the ophthalmologist. Further, they focus on an early diagnosis through identification of specific clinical biomarkers and on management in way of early stoppage of the drug and supportive therapy. This statement also describes the mechanism of reporting a case of toxic optic neuropathy through the Pharmacovigilance Programme of India and emphasizes the need for spreading awareness regarding vision-threatening adverse effects among patients and healthcare workers., Competing Interests: None

Background: Ethambutol ocular toxicity is a major problem during combination chemotherapy for Mycobacterium avium complex (MAC) pulmonary disease (MAC-PD) due to years-long therapy for MAC., Objectives: This study aimed to identify the lower dose of daily ethambutol that can reduce ocular toxicity., Methods: We retrospectively reviewed the medical records of 312 patients who visited The University of Tokyo Hospital between January 2007 and December 2017 for nontuberculous mycobacterial pulmonary disease. Seventy-six patients with MAC-PD who were treated with combination chemotherapy for the first time were analyzed in this study., Results: Ethambutol was discontinued because of visual symptoms in 13 patients (17%), 7 of whom were diagnosed with ethambutol ocular neuropathy. The dose per body weight was significantly higher in patients who developed ocular neuropathy than in those who did not (15.4 mg/kg/d vs. 12.5 mg/kg/d, respectively; p = 0.048). We assigned patients to higher or lower dose groups according to the median dose of 12.5 mg/kg/d. Although ocular neuropathy developed in 6 out of 38 patients in the higher dose group, ocular neuropathy developed in 1 out of 38 patients in the lower dose group (16% vs. 3%, respectively; p = 0.038). The failures of sputum culture conversion and radiological improvement were not significantly different between the two groups (p = 0.638 and 0.305, respectively). Macrolide resistance developed in one patient per group during follow-up (3% per group, p = 0.945)., Conclusions: A lower dose of ethambutol may reduce ocular toxicity without radiological deterioration for pulmonary MAC infection., Competing Interests: Conflict of Interest The authors declare no conflict of interest associated with this study., (Copyright © 2021. Published by Elsevier B.V.)

Ethambutol is an integral part of Antitubercular therapy (ATT) and is often associated with optic neuropathy, However, neuroimaging of ethambutol induced optic neuropathy has been sparsely reported in the literature. We describe the case of a 45-year male patient, diagnosed as Tuberculous spondylodiscitis and was on ATT. Four months after ATT initiation, he presented with visual blurring in both the eyes with bitemporal hemianopia and central scotomas. Visual evoked potential (VEP) revealed prolonged latencies in N75 and P100 waveforms bilaterally. Magnetic Resonance Imaging (MRI) showed optic chiasma and bilateral optic tract hyperintensities on 3D Fluid Attenuated Inversion Recovery (FLAIR) and 3D Double Inversion Recovery (DIR) sequences. Ethambutol was discontinued immediately. On follow-up after 8 weeks, visual acuity reversed back to normal in both eyes., Competing Interests: Conflicts of interest The authors have none to declare., (Copyright © 2020 Tuberculosis Association of India. Published by Elsevier B.V. All rights reserved.)

Ethambutol-induced optic neuropathy (EON) is a well-known complication, although low-dose ethambutol seldom causes EON. An 85-year-old man with non-tuberculous mycobacterial lung disease was taking antibiotics, including low-dose ethambutol. On day 85 of treatment, the diagnosis of EON was made. Despite prior discontinuation, his best corrected visual acuity drastically deteriorated from 20/17 (right eye) and 20/20 (left eye) to 20/330 (right eye) and 20/1,000 (left eye) within 3 weeks, and this symptom did not resolve. To our knowledge, there have been no reported cases with drastically progressing and irreversible EON even after the withdrawal of low-dose and short-term ethambutol.

Background: We investigated structural injury patterns in the peripapillary retinal nerve fibre layer (p-RNFL) and ganglion cell inner plexiform layer (GCIPL) caused by ethambutol treatment., Methods: Sixty-four patients undergoing ethambutol treatment at Zhejiang Chinese Medicine and Western Medicine Integrated Hospital were recruited. Fourteen (14) exhibited visual dysfunction (abnormal group), and the remaining 50 had no visual dysfunction (subclinical group). The thickness of the p-RNFL, total macular retina layer and GCIPL were measured using Cirrus-HD Optical coherence tomography (Cirrus-HD OCT, Cirrus high-definition optical coherence tomography), and compared with 60 healthy, age-matched controls., Results: The p-RNFL thickness was similar in both subclinical and control groups. When compared with the control group, p-RNFL thickness in the abnormal group was significantly increased in the inferior and superior quadrants (GEE, P = 0.040, P = 0.010 respectively). In contrast with the subclinical group, p-RNFL thickness in the inferior quadrant was increased in the abnormal group (GEE, P = 0.047). The GCIPL thickness in the inferonasal and inferior sectors was significantly deceased in the subclinical group when compared with controls (GEE, P = 0.028, P = 0.047, respectively). The average and minimum value of GCIPL thickness, and thickness in the superonasal, inferior, inferotemporal, superotemporal and superior sectors were significantly decreased in the abnormal group when compared with controls (GEE, P = 0.016, P = 0.001, P = 0.028, P = 0.010, P = 0.012, P = 0.015, P = 0.010, respectively). The cube average macular thickness (CAMT) in the abnormal group was significantly thinner than controls (GEE, P = 0.027)., Conclusions: GCIPL measurements using Cirrus-HD OCT detected retinal ganglion cell layer loss following ethambutol treatment, before visual dysfunction occurred.

There has been change in the guidelines for the management of tuberculosis in India. The new guidelines advocate the daily use of Ethambutol for both intensive and continuation phase of the treatment. This may be a matter of concern as increased cumulative dose may lead to increase in incidence of toxic optic neuropathy due to ethambutol. Indian Neuro-Ophthalmology Society has taken cognizance of the issue and has come-up with guidelines for prevention and early detection of the toxic optic neuropathy., (© Journal of the Association of Physicians of India 2011.)

Treatment outcomes among multidrug-resistant tuberculosis (MDR-TB) patients receiving ethambutol, cycloserine, or terizidone as part of a standardized regimen were compared, determining occurrence of serious adverse drug events (SADEs). Newly diagnosed adult MDR-TB patients were enrolled between 2000 and 2004, receiving a standardized multidrug regimen for 18 to 24 months, including ethambutol, cycloserine, or terizidone. Cycloserine and terizidone were recorded individually. SADEs and factors associated with culture conversion and unfavorable treatment outcomes (default, death, treatment failure) were determined. Of 858 patients, 435 (51%) received ethambutol, 278 (32%) received cycloserine, and 145 (17%) received terizidone. Demographic and baseline clinical data were comparable. Successful treatment occurred in 56%, significantly more in patients receiving cycloserine (60%) and terizidone (62%) than in those receiving ethambutol (52% [ P  = 0.03]). Defaults rates were 30% in ethambutol patients versus 15% and 11% for cycloserine and terizidone patients, respectively. Terizidone was associated with fewer unfavorable outcomes (adjusted odds ratio [AOR], 0.4; P  = 0.008; 95% confidence interval [CI], 0.2 to 0.8). Patients receiving cycloserine were more likely to achieve culture conversion than those receiving ethambutol or terizidone (AOR, 2.2; P  = 0.02; 95% CI, 1.12 to 4.38). Failure to convert increased the odds of unfavorable outcomes (AOR, 23.7; P  < 0.001; 95% CI, 13 to 44). SADEs were reported in two patients receiving ethambutol, seven patients receiving cycloserine, and three receiving terizidone ( P  = 0.05). Ethambutol was associated with high culture conversion and default rates. Cycloserine achieved higher culture conversion rates than terizidone. Fewer patients on terizidone experienced SADEs, with lower default rates. The differences that we observed between cycloserine and terizidone require further elucidation., (Copyright © 2020 American Society for Microbiology.)

We evaluated changes in the pupillary light reflex (PLR) of ethambutol (EMB)-induced optic neuropathy and analyzed the correlations between PLR parameters and other structural changes in EMB-induced optic neuropathy. This retrospective, observational, case-control study involved thirty-two eyes of 17 patients with EMB-induced optic neuropathy (EON group), sixty eyes of 60 patients without EMB-induced optic neuropathy (non-EON group) while taking ethambutol, and forty-five eyes of 45 normal controls. PLR was measured by digital pupillometry. The clinical characteristics, optical coherence tomography measurements and PLR parameters including pupil diameter, constriction latency, constriction ratio/velocity, and dilation velocity were noted. The differences in PLR measurements were compared among the three groups. Correlations between PLR parameters and other structural parameters in EMB-induced optic neuropathy were evaluated. The pupillary constriction ratio, constriction and dilation velocities were significantly reduced in the EON group compared to the non-EON group and controls (all P < 0.05). In EMB-induced optic neuropathy, average outer macular ganglion cell layer (mGCL) thickness showed a significant correlation with the pupillary constriction ratio (ß = 4.14, P = 0.003) and maximal constriction velocity (ß = 1.08, P < 0.001). This study confirmed that pupillary constriction and dilation velocities were significantly decreased in patients with EMB-induced optic neuropathy, compared to normal controls. Digital pupillometry may be a useful tool in the evaluation of EMB-induced optic neuropathy.

Rationale: Whether two-drug therapy (clarithromycin and ethambutol) for Mycobacterium avium complex (MAC) pulmonary disease contributes to the development of macrolide-resistant MAC is unclear., Objective: To compare the incidence of macrolide-resistant MAC between patients treated with two-drug therapy (clarithromycin and ethambutol) and the standard three-drug therapy (clarithromycin, ethambutol, and rifampicin) for MAC pulmonary disease., Methods: We retrospectively reviewed 147 patients with treatment-naive MAC pulmonary disease who had received two-drug therapy (n = 47) or three-drug therapy (n = 100) between 1997 and 2016 at National Hospital Organization, Tenryu Hospital, Hamamatsu, Japan. The risk of development of macrolide-resistant MAC was evaluated by calculating the cumulative incidence rate using Gray's test., Results: The median follow-up period was 74.5 months. During the follow-up period, one of the 47 patients (2.1%) in the two-drug group developed macrolide-resistant MAC, compared to 12 of the 100 patients (12.0%) in the three-drug group. The cumulative incidence rate of macrolide-resistant MAC was lower in the two-drug group than in the three-drug group (0.0023; 95% confidence interval, 0.002 to 0.107 versus 0.200; 95% confidence interval, 0.100 to 0.324, p = 0.0593)., Conclusions: These results suggest that two-drug treatment with clarithromycin and ethambutol for MAC pulmonary disease does not lead to a higher incidence of resistance acquisition to clarithromycin than the standard three-drug treatment., Competing Interests: Declaration of competing interest All authors have no potential conflicts of interest., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: Government of India's Revised National TB Control Programme (RNTCP) has begun implementing daily fixed dose combination (FDC) anti-TB treatment regimen for drug sensitive TB patients in which ethambutol is given for six months. Prolonged ethambutol use is known to cause ocular adverse drug events (ADE)., Objectives: To assess the magnitude of ocular ADEs in adult drug sensitive TB patients initiated on daily FDCs and to describe the demographic and clinical profile of patients with ocular ADEs., Methods: We conducted a retrospective cohort study involving review of RNTCP records of all adult (age >14 years) drug sensitive TB patients initiated on daily FDCs between1 st January 2018 and 31st July 2018 in Thiruvananthapuram district, Kerala State, India., Results: 714 patients were initiated on daily FDCs during the study period. It was unknown whether all patients had undergone assessment for ocular ADEs. However, of these 714 patients, 8 patients (1.1%) were documented to have had ocular ADEs. Seven of these 8 patients had received ethambutol more than 15 mg/kg body weight and had developed ocular symptoms (decreased/blurring of vision) 3 months after TB treatment initiation. Ethambutol was stopped in all these 8 patients. In 5 patients it was recorded that ocular ADEs had resolved following stoppage of ethambutol and in the remaining it was unknown., Conclusion: The study confirms the occurrence of ocular ADEs among drug sensitive TB patients on daily FDCs and recommends strengthening of systems for assessing, documenting and managing ocular ADE., Competing Interests: Conflicts of interest The authors have none to declare., (Copyright © 2020 Tuberculosis Association of India. Published by Elsevier B.V. All rights reserved.)

Background: Long-term administration of ethambutol (EMB) for Mycobacterium avium complex lung disease (MAC-LD) sometimes leads to permanent discontinuation of EMB due to various adverse events. This study aimed to investigate treatment outcomes after discontinuation of EMB., Methods: Among patients diagnosed with MAC-LD between January 2001 and December 2014, 508 patients whose treatment was initiated with standard regimen until May 2018 were enrolled at a tertiary referral center in Korea. Of these 508 patients, 60 (11.8%) discontinued EMB due to various adverse effects. Among these 60 patients, treatment outcomes were analyzed for 44 patients by comparing their outcomes with those of matched subjects who received the standard treatment regimen without EMB discontinuation., Results: The mean age of the 60 patients who discontinued EMB was 64.4 years. Ocular toxicity was the most common cause of discontinuation of EMB (75.0%, 45/60). The mean duration of EMB administration before its discontinuation was 7.0 ± 4.6 months. The treatment failure rate of the 44 patients with EMB discontinuation analyzed for treatment outcome was 29.6%, which was higher than that of the matched patients who received the standard regimen (18.3%), although the difference was not significant ( P = 0.095). Of these 44 patients, EMB was substituted with later-generation fluoroquinolone in 23 patients, and the treatment failure rate of these 23 patients was significantly higher than that of the matched patients who received the standard regimen (39.1% vs. 19.3%, P = 0.045)., Conclusion: These findings suggest that treatment outcomes are unsatisfactory in patients with MAC-LD who discontinue EMB owing to adverse events. Notably, there was a statistically significant high failure rate in patients who were prescribed fluoroquinolone to replace EMB., Competing Interests: The authors have no potential conflicts of interest to disclose., (© 2020 The Korean Academy of Medical Sciences.)

Six-month combination regimens could lead to serious hepatotoxicity, which may limit the clinical use of antituberculosis drugs. ABCC transporters are critical to the influx and efflux of compounds into and out of cells. The aim of this study was to explore whether the genetic variants in ABCC genes were related to the development of antituberculosis drug-induced hepatotoxicity. Here, we screened and genotyped 39 single-nucleotide polymorphisms of 13 ABCC genes in 746 eligible patients treated by first-line antituberculosis drugs in Western China Hospital. Genomic DNA was extracted from a peripheral blood sample of each patient, and clinical symptoms and laboratory results were recorded regularly. We found that the incidence rate of hepatotoxicity was 15.8% in the western Chinese Han population. As a result, the ABCC2 rs3740065 genotype, sex, and the baseline level of alanine aminotransferase are independent risk factors of antituberculosis drug-induced hepatotoxicity, with P values of .008, .014, and <.001, respectively. Our findings revealed a fraction of the underlying mechanism of hepatotoxicity, and larger validation studies on different populations are warranted to confirm these findings., (© 2019, The American College of Clinical Pharmacology.)