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Aims of the Study: Our aim was to explore drug-induced liver injury (DILI) in Switzerland using the real-world data of the global pharmacovigilance database VigiBaseÔ, with a special focus on the new drug class of checkpoint inhibitors. This is the first study investigating drug-related hepatic disorders in Switzerland in a global pharmacovigilance database., Methods: This was a retrospective study analysing the ICSRs (individual case safety reports) of the global pharmacovigilance database VigiBaseÔ. We explored all ICSRs submitted in Switzerland within the last 10 years (1 July 2010 to 30 June 2020). For data extraction, the standardised MedDRA query (SMQ) “narrow drug-related hepatic disorders – severe events only” was applied. The ICSRs, drug-reaction pairs and adverse drug reactions were analysed descriptively, including a special focus on checkpoint inhibitors. For comparing the hepatic adverse drug reactions of pembrolizumab, nivolumab and ipilimumab, the reporting odds ratios (RORs) were calculated in a disproportionality analysis., Results: In total, 2042 ICSRs could be investigated, comprising 10,646 drugs and 6436 adverse drug reactions. Gender was equally distributed between male and female. Patients were on average 57 years old. The mortality rate was high, with fatal adverse reactions in over 10% of cases. On average, patients used five drugs including two suspected drugs. Paracetamol, amoxicillin/clavulanic acid, esomeprazole and atorvastatin ranked among the most frequently suspected drugs for severe drug-related hepatic disorders. However, VigibaseÔ data are not appropriate for judging causality and these results should be interpreted with caution owing to the possible influences of comedication or comorbidity. An average of three adverse drug reactions per ICSR were reported, most frequently including hepatocellular injury, cholestatic liver injury, and liver injury. For checkpoint inhibitors, hepatitis was the most frequently reported hepatic adverse drug reaction. In comparison with nivolumab and ipilimumab, pembrolizumab had a significantly higher ROR for hepatitis (2.41, p = 0.016), but also a lower ROR for autoimmune hepatitis (0.11, p = 0.009)., Conclusion: Our findings highlight the importance for healthcare providers in Switzerland to pay special attention to possible drug-induced liver injuries because of their high mortality rate. The analysis of real-world data confirms the previous assumption that hepatitis is the most frequent hepatic adverse event for checkpoint inhibitors. Further clinical studies are warranted to directly compare hepatic adverse drug reactions to different checkpoint inhibitors.

Purpose: Heart failure is among the leading causes for hospitalization in Europe. In this study, we evaluate potential precipitating factors for hospitalization for heart failure and shock., Methods: Using Swiss claims data (2014-2015), we evaluated the association between hospitalization for heart failure and shock, and prescription of oral potassium supplements, non-steroidal anti-inflammatory drugs (NSAIDs), and amoxicillin/clavulanic acid. We conducted case-crossover analyses, where exposure was compared for the hazard period and the primary control period (e.g., 1-30 days before hospitalization vs. 31-60 days, respectively). Conditional logistic regression was applied and subsequently adjusted for addressing potential confounding by disease progression. Sensitivity analyses were conducted and stratification for co-medication was performed., Results: We identified 2185 patients hospitalized with heart failure or shock. Prescription of potassium supplements, NSAIDs, and amoxicillin/clavulanic acid was significantly associated with an increased risk for hospitalization for heart failure and shock with crude odds ratios (OR) of 2.04 for potassium (95% CI 1.24-3.36, p = 0.005, 30 days), OR 1.8 for NSAIDs (95% CI 1.39-2.33, p < 0.0001, 30 days), and OR 3.25 for amoxicillin/clavulanic acid (95% CI 2.06-5.14, p < 0.0001, 15 days), respectively. Adjustment attenuated odds ratios, while the significant positive association remained (potassium OR 1.70 (95% CI 1.01-2.86, p = 0.046), NSAIDs OR 1.50 (95% CI 1.14-1.97, p = 0.003), and amoxicillin/clavulanic acid OR 2.26 (95% CI 1.41-3.62, p = 0.001)., Conclusion: Prescription of potassium supplements, NSAIDs, and amoxicillin/clavulanic acid is associated with increased risk for hospitalization. Underlying conditions such as pain, electrolyte imbalances, and infections are likely contributing risk factors. Physicians may use this knowledge to better identify patients at risk and adapt patient management.

Background: Rising health care costs are a major public health issue. Thus, accurately predicting future costs and understanding which factors contribute to increases in health care expenditures are important. The objective of this project was to predict patients healthcare costs development in the subsequent year and to identify factors contributing to this prediction, with a particular focus on the role of pharmacotherapy., Methods: We used 2014-2015 Swiss health insurance claims data on 373'264 adult patients to classify individuals' changes in health care costs. We performed extensive feature generation and developed predictive models using logistic regression, boosted decision trees and neural networks. Based on the decision tree model, we performed a detailed feature importance analysis and subgroup analysis, with an emphasis on drug classes., Results: The boosted decision tree model achieved an overall accuracy of 67.6% and an area under the curve-score of 0.74; the neural network and logistic regression models performed 0.4 and 1.9% worse, respectively. Feature engineering played a key role in capturing temporal patterns in the data. The number of features was reduced from 747 to 36 with only a 0.5% loss in the accuracy. In addition to hospitalisation and outpatient physician visits, 6 drug classes and the mode of drug administration were among the most important features. Patient subgroups with a high probability of increase (up to 88%) and decrease (up to 92%) were identified., Conclusions: Pharmacotherapy provides important information for predicting cost increases in the total population. Moreover, its relative importance increases in combination with other features, including health care utilisation.

Aims of the Study: Although systemic drugs can exert local effects on the eye, ophthalmology is a medical specialty with perhaps the fewest assessed adverse drug reactions (ADRs), representing a particular challenge in pharmacovigilance. Our aim was to quantify ADRs in ophthalmology in Switzerland, with a focus on angiogenesis inhibitors., Methods: Individual case safety reports (ICSRs) on suspected ADRs reported in Switzerland from January 1991 to June 2016 were extracted from the WHO Global ICSR database, VigiBase&trade;. ICSRs were analysed in relation to treatment duration, patient age, route of administration, patient sex and reported symptoms., Results: A total of 80,515 ICSRs were reported in Switzerland during the reference period. Reactions linked to eye disorders accounted for 2793 (3.5%) cases. The main Anatomic Therapeutic Chemical / Defined Daily Dose drug classes associated with eye disorders were drugs acting on the nervous system (27.7%) followed by drugs &ldquo;acting on sensory organs&rdquo; (20.2%) and antineoplastic agents (18.0%). Most cases involved adult patients (70.6%). Patients over 60 years accounted for 815 (29.2%) ICSRs, and reactions in children were significantly less frequent (8.2%). Older patients were exposed to a higher number of drugs, and the majority of serious reactions involved children and older patients. A significant positive correlation between polypharmacy and seriousness of reported reactions was observed. The reported drugs were categorised as &ldquo;suspected&rdquo; in 51.1%, &ldquo;concomitant&rdquo; in 43.3% and &ldquo;interacting&rdquo; in 2.6% of cases. &ldquo;Visual impairment&rdquo; was the most commonly reported adverse reaction, experienced by 635 (22.7%) of patients (7.2% of all reported eye-related symptoms). The majority of reactions were transient, as 4173 (47.1%) completely resolved. Severe reactions included fatal outcome in 18 patients (0.6%) and blindness in 78 patients (2.6%). Since 2000, the intravitreous vascular endothelial growth factor (VEGF) inhibitors bevacizumab, aflibercept and ranibizumab accounted for 99 ICSRs. Retinal haemorrhage (reporting odds ratio [ROR] 10.36, 95% confidence interval [95% CI] 2.65&ndash;40.50; p &lt;0.001), blindness (ROR 3.73, 95% CI 1.08&ndash;12.96; p = 0.04) and uveitis (ROR 6.91, 95% CI 1.64&ndash;29.13; p = 0.01) were significantly more frequently reported for aflibercept than for bevacizumab and ranibizumab., Conclusions: ADRs that affect the eye represented 3.5% of all pharmacovigilance reports during the reporting period. Whereas retinal haemorrhage and uveitis are known adverse reactions to angiogenesis inhibitors, the reported cases of blindness and death should heighten awareness of potential safety issues associated with VEGF inhibitors for the treatment of proliferative eye disorders.

Background: Potential drug-drug interactions (pDDIs) are described in various case reports, but few studies have evaluated the impact of specific combinations on a population level., Objective: To analyze the type and frequency of multiple contraindicated (X-pDDIs) and major interactions (D-pDDIs) and to subsequently assess the impact of the particular combination of tizanidine and ciprofloxacin on outpatient physician visits and hospitalizations., Methods: Anonymized Swiss claims data from 524 797 patients in 2014-2015 were analyzed. First, frequencies of X- and D-pDDIs were calculated. Next, a retrospective cohort study was conducted among patients prescribed tizanidine and ciprofloxacin (exposed, n = 199) or tizanidine and other antibiotics (unexposed, n = 960). Hospitalizations and outpatient physician visits within 7, 14, and 30 days after initiation of antibiotic therapy were evaluated using multiple binary logistic regression and multiple linear regression., Results: The relative frequencies of X- and D-pDDIs were 0.4% and 6.65%, respectively. In the cohort study, significant associations between exposure to tizanidine and ciprofloxacin and outpatient physician visits were identified for 14 and 30 days (odds ratio [OR] = 1.61 [95% CI = 1.17-2.24], P = 0.004, and OR = 1.59 [95% CI = 1.1-2.34], P = 0.016). A trend for increased risk of hospitalization was found for all evaluated time periods (OR = 1.68 [95% CI = 0.84-3.17], OR = 1.52 [95% CI = 0.63-3.33], and OR = 2.19 [95% CI = 0.88-5.02]). Conclusion and Relevance: The interaction between tizanidine and ciprofloxacin is not only relevant for individual patients, but also at the population level. Further investigation of the impact of other clinically relevant DDIs is necessary to improve patient safety and reduce avoidable health care utilization.

Unlabelled: Although paediatric patients frequently suffer from intoxications with atypical antipsychotics, the number of studies in young children, which have assessed the effects of acute exposure to this class of drugs, is very limited. The aim of this study was to achieve a better characterization of the acute toxicity profile in young children of the atypical antipsychotics clozapine, olanzapine, quetiapine, and risperidone. We performed a multicentre retrospective analysis of cases with atypical antipsychotics intoxication in children younger than 6 years, reported by physicians to German, Austrian, and Swiss Poisons Centres for the 9-year period between January 1, 2001 and December 31, 2009. One hundred and six cases (31 clozapine, 29 olanzapine, 12 quetiapine, and 34 risperidone) were available for analysis. Forty-seven of the children showed minor, 28 moderate, and 2 severe symptoms. Twenty-nine cases were asymptomatic. No fatalities were recorded. Symptoms predominantly involved the central nervous and cardiovascular systems. Minor reduction in vigilance (Glasgow Coma Scale score >9) (62 %) was the most frequently reported symptom, followed by miosis (12 %) and mild tachycardia (10 %). Extrapyramidal motor symptoms were observed in one case (1 %) after ingestion of risperidone. In most cases, surveillance and supportive care were sufficient to achieve a good outcome, and all children made full recovery., Conclusions: Paediatric antipsychotic exposure can result in significant poisoning; however, in most cases only minor or moderate symptoms occurred and were followed by complete recovery. Symptomatic patients should be monitored for central nervous system depression and an electrocardiogram should be obtained.

Background: Fire eater's lung (FEL) is a distinct form of acute chemical toxic pneumonitis, which is caused by aspiration of flammable petrochemical derivatives used by street performers for 'fire eating'. The optimal management of this condition has not yet been determined., Objective: The aim of this study was to investigate patient characteristics, clinical features, treatment, and outcome of FEL., Methods: A single-center retrospective review of consecutive cases of FEL in children and adults reported to a national poison center (the Swiss Toxicological Information Center) between 1995 and 2012., Results: 123 cases (83.7% males, mean age 21.9 years) were included. The most frequently reported symptom was cough (50.4%), followed by chest pain (45.5%), and fever (35.8%). Dyspnea was reported by 23.6%. Cough (p = 0.002) and chest pain (p = 0.02) were significantly more prevalent in subjects reporting to have aspirated the fuel compared to those who have swallowed it or who did not perceive poison exposure. A pulmonary infiltrate was detected in 83% of the cases in whom chest X-ray was performed. Overall, 22% were treated with an antibiotic agent for a mean duration of 10.4 days. Corticosteroids were administered in 4.9%. All showed complete recovery irrespective of the therapeutic management., Conclusion: The combination of intense pleuritic chest pain, cough, dyspnea, and fever, or any of these symptoms after 'fire eating' or erroneous swallowing of a petroleum distillate should alert the clinician to the diagnosis of FEL. Early antibiotic treatment of severe cases seems justified, considering that clinical, laboratory, and radiologic findings of FEL are overlapping with bacterial superinfection., (Copyright © 2013 S. Karger AG, Basel.)

Objectives: To describe clinical effects, circumstances of occurrence, management and outcomes of cases of inadvertent administration of medications by an incorrect parenteral route., Methods: Retrospective single-center consecutive review of parenteral route errors of medications, reported to our center between January 2006 and June 2010. We collected demographic data and information on medications, route and time of administration, severity of symptoms/signs, treatment, and outcome., Results: Seventy-eight cases (68 adults, 10 children) were available for analysis. The following wrong administration routes were recorded: paravenous (51%), intravenous (33%), subcutaneous (8%), and others (8%). Medications most frequently involved were iodinated x-ray contrast media (11%) and iron infusions (9%). Twenty-eight percent of the patients were asymptomatic and 54% showed mild symptoms; moderate and severe symptoms were observed in 9% and 7.7%, respectively, and were mostly due to intravenous administration errors. There was no fatal outcome. In most symptomatic cases local nonspecific treatment was performed., Conclusions: Enquiries concerning administration of medicines by an incorrect parenteral route were rare, and mainly involved iodinated x-ray contrast media and iron infusions. Most events occurred in adults and showed a benign clinical course. Although the majority of exposures concerned the paravenous route, the occasional severe cases were observed mainly after inadvertent intravenous administration.

Background: Picking wild mushrooms is a popular pastime in Switzerland. Correct identification of the species is difficult for laypersons. Ingestion of toxic mushrooms may result in serious toxicity, including death. The aim of the study is to analyze and describe the circumstances of exposure to mushrooms, and to define the clinical relevance of mushroom poisoning for humans in Central Europe., Materials and Methods: We performed a retrospective case study and analyzed all inquiries concerning human exposures to mushrooms (n = 5638, 1.2% of all inquiries) which were reported to the Swiss Toxicological Information Centre between January 1995 and December 2009., Results: The most frequent reason for contacting the poison center in cases of adult exposure was toxicity resulting from edible species. Pediatric exposure predominantly occurred from mushrooms found around the home. Severe symptoms have not only been observed after ingestion of non-amatoxin-containing toxic mushrooms, i.e. Boletus sp. and Cortinarius sp., but also after meals of edible species. The mortality of confirmed amatoxin poisonings was high (5/32) compared to other reports., Conclusions: Inquiries regarding mushroom poisoning were a relatively infrequent reason for contacting the poison center. Nevertheless, accidental ingestion of toxic mushrooms can be responsible for severe or fatal poisonings. Although pediatric exposure to mushrooms found around the home has not led to serious toxicity in this study, prevention of exposure is warranted. Inspection of wild mushrooms by a certified mushroom expert or a mycologist seems to be a safe procedure which should be recommended., (Copyright © 2012 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.)

Purpose: Our aim was to study drug interactions and dose adjustments in patients with renal impairment in the discharge medication of surgical inpatients and to evaluate the strengths and limitations of clinical decision support software (CDSS) for this task., Methods: This was a cross-sectional study involving 509 surgical patients of a primary care hospital. We developed a customized interface for the CDSS MediQ, which we used for automated retrospective identification of drug interactions in the patients' discharge medication. The clinical relevance of the interactions was evaluated based on the Zurich Interaction System (ZHIAS) that incorporates the operational classification of drug interactions (ORCA). Prescriptions were further analyzed for recommended dose adjustments in patients with a glomerular filtration rate <60 ml/min., Results: For the total of 2,729 prescriptions written for the 509 patients enrolled in the study, MediQ generated 2,558 interaction alerts and 1,849 comments. Among these were ten "high danger" and 551 "average danger" alerts that we reclassified according to ORCA criteria. This reclassification resulted in ten contraindicated combinations, 77 provisionally contraindicated combinations, and 310 with a conditional and 164 with a minimal risk of adverse outcomes. The ZHIAS classification also provides categorical information on expected adverse outcomes and management recommendations, which are presented in detail. We identified 56 prescriptions without a recommended dose adjustment for impaired renal function., Conclusions: CDSS identified a large number of drug interactions in surgical discharge medication, but according to ZHIAS criteria only a minor fraction of these appeared to involve a substantial risk to the patient. CDSS should therefore aim at reducing over-alerting and improve usability in order to become more efficacious in terms of the prevention of adverse drug events in clinical practice.

Purpose: The incidence of adverse drug events (ADE) is an important parameter in determining the quality of medical care. We identified the probability that a specific data source would identify ADEs in patients on the oncology ward, that could be assigned to one substance., Methods: We captured all medical adverse events (AE) from five different data sources. Each AE was determined to be drug-related according to the WHO criteria and classified according to the severity, category, and causality of the ADE., Results: The study recorded 129 patients with 252 hospitalizations over a 5-month period. A total of 3,341 medical events were captured and resulted in 1,121 ADEs. In 122 patients, at least one ADE (95%) was observed. Only 39 hospitalizations were believed not to have an ADE (15%). No ADE was captured by all data sources. The patient record captured 550, the nursing record 569, the laboratory tests 387, the questionnaire 63, and the event monitoring during grand rounds 141 ADEs. Only the nursing record and the laboratory tests had a significantly different probability of observing indicative ADEs., Conclusion: For all AEs reported in the data sources, physicians and nurses were the best source for ADEs. Data sources differed in identifying indicative ADEs and were influenced by specific patient parameters.

Introduction: Human contact with potentially toxic plants, which may occur through abuse or by accident or attempted suicide, is frequent and sometimes results in clinically significant toxicity., Objective: The aim of the present study was to identify which plants may lead to severe poisoning, and to define the clinical relevance of plant toxicity for humans in Switzerland., Methods: We analyzed 42,193 cases of human plant exposure and 255 acute moderate, severe, and lethal poisonings, which were reported to the Swiss Toxicological Information Centre between January 1995 and December 2009., Results: Plant contact was rarely responsible for serious poisonings. Lethal intoxications were extremely rare and were caused by plants with cardiotoxic (Taxus baccata) or mitosis-inhibiting (Colchicum autumnale) properties., Conclusions: Most often, plant contact was accidental and patients remained asymptomatic or developed mild symptoms, which fully resolved within a short time.

Aim: To study whether the glucocorticoid receptor (GR/NR3C1) gene haplotypes influence the steroid therapy outcome in inflammatory bowel disease (IBD)., Methods: We sequenced all coding exons and flanking intronic sequences of the NR3C1 gene in 181 IBD patients, determined the single nucleotide polymorphisms, and predicted the NR3C1 haplotypes. Furthermore, we investigated whether certain NR3C1 haplotypes are significantly associated with steroid therapy outcomes., Results: We detected 13 NR3C1 variants, which led to the formation of 17 different haplotypes with a certainty of > 95% in 173 individuals. The three most commonly occurring haplotypes were included in the association analysis of the influence of haplotype on steroid therapy outcome or IBD activity. None of the NR3C1 haplotypes showed statistically significant association with glucocorticoid therapy success., Conclusion: NR3C1 haplotypes are not related to steroid therapy outcome.

Context: Seizures are a recognized complication of acute overdose with the racemic (1:1 ratio of R- and S-enantiomers) selective serotonin reuptake inhibitor antidepressant citalopram., Objective: We tested the hypothesis that escitalopram (the therapeutically active S-enantiomer of citalopram) causes fewer seizures in overdose than citalopram at comparable doses of the S-enantiomer., Methods: Multicenter retrospective review of cases with citalopram and escitalopram overdose reported to German, Austrian, and Swiss Poisons Centers between 1997 and 2006., Results: 316 citalopram and 63 escitalopram cases were analyzed. Somnolence, nausea, vomiting, tachycardia, QT prolongation, and tremor occurred with similar frequency in both groups. There was a striking difference in the frequency of single and multiple seizures: 43 cases (13.5%) in the citalopram group and 1 case (1.6%) with a single seizure in the escitalopram group (p=0.0065)., Discussion and Conclusions: At comparable ingested doses of the S-enantiomer, the symptom profile for citalopram and escitalopram intoxications is similar except for seizures that occur more frequently in citalopram than in escitalopram poisoning.

Objective: More than 11% of the Caucasian population are heterozygous or homozygous carriers of thiopurine S-methyltransferase (TPMT) mutants and are at risk for toxic side effects when treated with thiopurine drugs. Therefore, screening for TPMT polymorphisms in a patient prior to prescribing these agents is recommended. The goal of this study was to determine a cut-off concentration of the TPMT activity assay beyond which genotyping of the TPMT gene should be performed., Methods: The TPMT activity of 240 unrelated Caucasian subjects was measured using high-performance liquid chromatography. Genotyping for the most frequent allelic variants, TPMT*2, *3A, *3B, *3C and *7 was performed by LightCycler technology and sequencing., Results: The inter-individual TPMT activity showed a range from 23 nmol MTG/g*Hb*h(-1) to 97 nmol MTG/g*Hb*h(-1) with a median of 56 nmol MTG/g*Hb*h(-1). Using a cut-off concentration of 45.5 nmol MTG/g*Hb*h(-1), a test sensitivity of 100% and a specificity of 89% were reached for heterozygous carriers of a TPMT mutation. We identified 1 carrier of TPMT*2, 14 carriers of TPMT*3A and 3 carriers of TPMT*3C, resulting in a TPMT heterozygosity prevalence of 7.5%., Conclusions: This study defines the cut-off value for the TPMT phenotyping assay at 45.5 nmol/g*Hb*h(-1), beyond which additional genotyping elucidates the individual risk for drug therapy. Using this cut-off concentration, the number of genotyping assays could be reduced by about 60%.

Background: Cadaveric liver transplantation (5-year survival >80%) represents the standard of care for end-stage liver disease (ESLD). Because the demand for cadaveric organs exceeds their availability, living-donor liver transplantation has gained increasing acceptance. Our aim was to assess the marginal cost-effectiveness of cadaveric and living-donor orthotopic liver transplantation (OLT) in adults with ESLD., Methods: Using a Markov model, outcomes and costs of ESLD treated (1) conservatively, (2) with cadaveric OLT alone, and (3) with cadaveric OLT or living-donor OLT were computed. The model was validated with published data. The case-based scenario consisted of data on all 15 ESLD patients currently on our waiting list (3 women, 12 men; median age, 48 years [range, 33-59 years]) and on the outcome of all OLT performed for ESLD at our institution since 1995 (n=51; actuarial 5-year survival 93%). Living-donor OLT was allowed in 15% during the first year of listing; fulminant hepatic failure and hepatocellular carcinoma were excluded., Results: Cadaveric OLT gained on average 6.2 quality-adjusted life-years (QALYs) per patient compared with conservative treatment, living-donor OLT, an additional 1.3 QALYs compared with cadaveric OLT alone. Marginal cost-effectiveness of a program with cadaveric OLT alone and a program with cadaveric and living-donor OLT combined were similar (E 22,451 and E 23,530 per QALY gained). Results were sensitive to recipient age and postoperative survival rate., Conclusions: Offering living-donor OLT in addition to cadaveric OLT improves survival at costs comparable to accepted therapies in medicine. Cadaveric OLT and living-donor OLT are cost-effective.

Aims: To explore drug exposure, frequency of adverse drug reactions (ADRs), types of ADRs, predisposing risk factors and ADR-related excess hospital stay in medical inpatients., Methods: Structured data regarding patient characteristics, 'events' (symptoms, laboratory results), diagnoses (ICD10) and drug therapy were collected using a computer-supported data entry system and an interface for data retrieval from electronic patient records. ADR data were collected by 'event monitoring' to minimize possible bias by the drug monitor. The causality of each event was assessed in relation to disease(s) and drug therapy., Results: The analysis included 4331 (100%) hospitalizations. The median observation period was 8 days. The median number of different drugs administered per patient and day was 6 and varied between 4 (Q1 ) and 9 (Q3 ) different drugs in 50% of all hospital days. In 41% of all hospitalizations at least one disease-unrelated event could be possibly attributed to drug therapy. Clinically relevant ADRs occurred in 11% of all hospitalizations. In 3.3% of all hospitalizations ADRs were the cause of hospital admission. The incidence of possibly ADR-related deaths was 1.4. Factors predisposing for clinically relevant ADRs were female gender and polypharmacy. ADR-related excess hospital stay accounted for 8. 6% of hospital days., Conclusions: These data demonstrate the feasibility of the developed 'event monitoring' system for quantitative analysis of ADRs in medical inpatients. With increasing numbers of recorded patients the pharmacoepidemiological database provides a valuable tool to study specific questions regarding drug efficacy and safety in hospitalized patients.