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Study objectives: To compare the safety and efficacy of oral azithromycin and levofloxacin in the treatment of outpatients with acute bacterial exacerbations of chronic bronchitis (ABECB). Design: Randomized, double-blinded, double-dummy, [...]

Background: Repeated infection with Chlamydia trachomatis increases the risk for serious sequelae: pelvic inflammatory disease, ectopic pregnancy, infertility, and chronic pelvic pain. A substantial proportion of women treated for C trachomatis infection are reinfected by an untreated male sex partner in the first several months after treatment. Effective strategies to ensure partner treatment are needed. Goal: The goal of the study was to determine whether repeated infections with C trachomatis can be reduced by giving women doses of azithromycin to deliver to male sex partners. Study Design: A multicenter randomized controlled trial was conducted among 1787 women aged 14 to 34 years with uncomplicated C trachomatis genital infection diagnosed at family planning, adolescent, sexually transmitted disease, and primary care clinics or emergency or other hospital departments in five US cities. Women treated for infection were randomized to one of two groups: patient-delivered partner treatment (in which they were given a dose of azithromycin to deliver to each sex partner) or self-referral (in which they were asked to refer their sex partners for treatment). The main outcome measure was C trachomatis DNA detected by urine ligase chain reaction (LCR) or polymerase chain reaction (PCR) by 4 months after treatment. Results: The characteristics of study participants enrolled in each arm were similar except for a small difference in the age distribution. Risk of reinfection was 20% lower among women in the patient-delivered partner treatment arm (87/728; 12%) than among those in the self-referral arm (106/726; 15%); however, this difference was not statistically significant (odds ratio, 0.80; 95% confidence interval, 0.62-1.05; P = 0.102). Women in the patient-delivered partner treatment arm reported high compliance with the intervention (82%). Conclusion: Patient-delivered partner treatment for prevention of repeated C trachomatis infection among women is comparable to self-referral and may be an appropriate option for some patients.

Study objective: To conduct a cost-effectiveness analysis of IV-to-oral regimens of azithromycin vs cefuroxime with or without erythromycin in the treatment of patients hospitalized with community-acquired pneumonia (CAP). Patients: Of [...]

Background: Azithromycin and doxycycline are recommended for treatment of genital Chlamydia trachomatis infection. A systematic review comparing these antibiotics could affect treatment guidelines. Goal: The goal was to perform a meta-analysis to evaluate the efficacy and tolerance of azithromycin versus doxycycline for genital chlamydial infection. Study Design: Studies were identified by searching computerized English-language databases for the period 1975 to August 2001, supplemented by a manual bibliographic search. Criteria for inclusion were (1) randomized trial design; (2) regimens of oral doxycycline (100 mg twice daily for 7 days) and oral azithromycin (1 g once); (3) males > 15 years of age and nonpregnant females > 15 years of age; (4) and evaluation of microbial cure at follow-up. Data were extracted on diagnostic assay, follow-up time, study design, sponsorship, patients' characteristics, adverse events, attrition rates, and outcomes. Results: Twelve trials met the inclusion criteria; 1543 patients were evaluated for microbial cure and 2171 for adverse events. Cure rates were 97% for azithromycin and 98% for doxycycline. Adverse events occurred in 25% and 23% of patients treated with azithromycin and doxycycline, respectively. After pooling of the data, differences in efficacy and risk were computed. The efficacy difference for microbial cure (0.01; 95% CI, -0.01-0.02) and the risk difference for adverse events (0.01; 95% CI, -0.02-0.04) between the two drugs were not statistically significant. Conclusion: Azithromycin and doxycycline are equally efficacious in achieving microbial cure and have similar tolerability. Further head-to-head trials comparing these antibiotics are unnecessary.

Background: Penicillin is the only medication currently recommended for treatment of early syphilis in non-penicillin-allergic patients. Preliminary data suggest that azithromycin may be effective for syphilis therapy. Study Design: This was a randomized, comparative pilot study of intramuscular injections of benzathine penicillin G and two oral azithromycin regimens for treatment of syphilis. Methods: We randomly assigned patients with early syphilis to treatment with either intramuscular injections of 2.4 million units of benzathine penicillin G or azithromycin administered orally, either as a single 2.0-g dose or as two 2.0-g doses given 1 week apart. Serological response to therapy was evaluated at 3, 6, 9, and 12 months following therapy. Participants whose rapid plasma reagin (RPR) test became nonreactive or whose RPR titer decreased [greater than or equal to] 2 dilutions were classified as responding to therapy. When serological tests did not show a response to therapy, the treatment was classified as a failure if RPR titers increased [greater than or equal to] 2 dilutions. Nonresponders were those whose serologic titers remained within [+ or -] 1 dilution of the initial RPR titer. Results: Cumulative response rates were as follows: benzathine penicillin G, 86% (12 of 14); azithromycin, 2.0-g single dose, 94% (16 of 17); and azithromycin, two 2.0-g doses given 1 week apart, 83% (24 of 29). Therapy failed for one patient treated with benzathine penicillin and one patient treated with the two-dose azithromycin regimen, whereas in six patients the clinical manifestations of infection resolved but there was no serological response. Conclusion: Oral therapy with 2.0 g of azithromycin as a single dose or as two doses 1 week apart is a promising alternative to therapy with benzathine penicillin G for syphilis and should be studied further.

The antibiotics amoxicillin and azithromycin are both equally effective in treating chlamydia infections in pregnant women. Chlamydia is the most common sexually transmitted disease and it can cause premature rupture of membranes, premature birth, fetal conjunctivitis, and fetal pneumonia.

Background: To treat chlamydial infection, the Centers for Disease Control and Prevention recommends either a single dose of azithromycin or a 7-day course of doxycycline. Cost is a concern with the single-dose regimen; compliance is a concern with the multidose regimen. Goal: To compare the use-effectiveness of azithromycin and doxycycline for preventing persistence or recurrence of Chlamydia trachomatis infection in women and to evaluate associated risk behaviors. Study Design: One hundred and ninety-six chlamydia-infected women and their sex partners were recruited into a randomized controlled trial of single-dose versus multidose regimens in seven public health clinics, with no incentives for enrollment, compliance, or follow-up. The outcome measure was a positive test for C.trachomatis by polymerase chain reaction testing at 1 month after treatment. Results: C. trachomatis positivity at 1 month was similar for women receiving single-dose (5.1%, 5/98) and multidose therapy (4.1%, 4/98). Reported compliance among 73 women taking multidose therapy was 94.5%. A twofold to threefold increased risk of chlamydial persistence or recurrence was observed among women who were [is less than or equal to] 24 and white or who reported: a recent new partner, multiple partners, or a partner who may have had multiple partners at the time of enrollment or that not all partners were treated during the 1-month follow-up period after initiation of treatment. Conclusions: The use-effectiveness of single-dose and multidose therapy was comparably high. Observed rates of persistence or recurrence were consistent with reported rates of pharmacological treatment failure. However, all women with C. trachomatis detected at 1 month had behavioral risk factors that may have contributed to reinfection., The frequency of continued infection or reinfection appears to be similar in women treated with either a single or multiple dose of medication for chlamydia. Follow-up tests for chlamydia were performed on 196 infected women one month after either a single dose of azithromycin or multiple doses of doxycycline. Follow-up tests showed positive results in 5.1% of the patients taking azithromycin and 4.1% of the patients taking doxycycline. Those patients engaging in high-risk behaviors were two to three times more likely to have a treatment failure with either medication.

Azithromycin is the most cost-effective drug for the prevention of Mycobacterium avium complex (MAC) infection in AIDS patients. Researchers compared the costs of azithromycin, rifabutin, and clarithromycin therapy, which cost between $994 and $2,185 per patient for prophylactic use.

Background: Treatment of shigellosis is currently limited by the high prevalence of multidrug-resistant strains of Shigella. Objective: To determine the efficacy of azithromycin in the treatment of shigellosis. Design: Randomized, double-blind clinical trial. Setting: Diarrhea treatment center in Dhaka, Bangladesh. Patients: 70 men with shigellosis that had lasted 72 hours or less. Interventions: Patients stayed in the hospital for 6 days. Thirty-four patients were randomly assigned to receive 500 mg of azithromycin on study day 1, followed by 250 mg once daily for 4 days; 36 patients were assigned to receive 500 mg of ciprofloxacin every 12 hours for 5 days. Measurements: Clinical treatment failure was considered to have occurred if frank dysentery persisted for 72 hours after therapy began or if on study day 5 a patient had more than six stools, had any bloody-mucoid stools, had more than one watery stool, or had an oral body temperature exceeding 37.8 [degrees]C. Bacteriologic treatment failure was considered to have occurred if Shigella strains could be isolated from a stool sample after study day 2. Therapy was considered either clinically or bacteriologically successful in patients who completed therapy and did not meet criteria for failure. Results: Therapy was clinically successful in 28 (82%) patients who received azithromycin and 32 (89%) patients who received ciprofloxacin (difference, -7% [95% [Cl, - 23% to 10%]). Therapy was bacteriologically successful in 32 (94%) patients receiving azithromycin and 36 (100%) patients receiving ciprofloxacin (difference, -6% [Cl, -14% to 2%]). Peak serum concentrations of azithromycin were equal to the minimum inhibitory concentration (MIC) of the infecting Shigella strains, whereas serum concentrations of ciprofloxacin were 28 times the MIC. Stool concentrations of both drugs were more than 200 times the MIC. Conclusion: Azithromycin is effective in the treatment of moderate to severe shigellosis caused by multidrug-resistant Shigella strains., Azithromycin appears to be effective in treating patients with Shigella infections. Stool frequency and consistency were evaluated and stool cultures were examined for Shigella organisms during five days of either azithromycin or ciprofloxacin treatment among 70 men with shigellosis. There was no evidence of Shigella organisms in stool samples following treatment among 94% of the patients taking azithromycin and all of the patients taking ciprofloxacin. Watery or bloody diarrhea did not persist nor was a fever documented among 82% of patients treated with azithromycin and 89% of patients treated with ciprofloxacin.

Objective: To determine whether azithromycin or amoxicillin is more efficacious for the treatment of erythema migrans skin lesions, which are characteristic of Lyme disease. Design: Randomized, double-blind, double-dummy, multicenter study. Acute manifestations and sequelae were assessed using a standardized format. Baseline clinical characteristics and response were correlated with serologic results. Patients were followed for 180 days. Setting: 12 outpatient centers in eight states. Patients: 246 adult patients with erythema migrans lesions at least 5 cm in diameter were enrolled and were stratified by the presence of flu-like symptoms (such as fever, chills, headache, malaise, fatigue, arthralgias, and myalgias) before randomization. Intervention: Oral treatment with either amoxicillin, 500 mg three times daily for 20 days, or azithromycin, 500 mg once daily for 7 days. Patients who received azithromycin also received a dummy placebo so that the dosing schedules were identical. Results: Of 217 evaluable patients, those treated with amoxicillin were significantly more likely than those treated with azithromycin to achieve complete resolution of disease at day 20, the end of therapy (88% compared with 76%; P = 0.024). More azithromycin recipients (16%) than amoxicillin recipients (4%) had relapse (P = 0.005). A partial response at day 20 was highly predictive of relapse (27% of partial responders had relapse compared with 6% of complete responders; P < 0.001). For patients treated with azithromycin, development of an antibody response increased the possibility of achieving a complete response (81% of seropositive patients achieved a complete response compared with 60% of seronegative patients; P = 0.043). Patients with multiple erythema migrans lesions were more likely than patients with single erythema migrans lesions (P < 0.001) to have a positive antibody titer at baseline (63% compared with 17% for IgM; 39% compared with 16% for IgG). Fifty-seven percent of patients who had relapse were seronegative at the time of relapse. Conclusions: A 20-day course of amoxicillin was found to be an effective therapeutic regimen for erythema migrans. Most patients were seronegative for Borrelia burgdorferi at the time of presentation with erythema migrans (65%) and at the time of relapse (57%)., Treatment with amoxicillin appears to give better results than treatment with azithromycin in patients with symptoms of Lyme disease. Researchers randomly assigned 217 adult patients displaying the typical Lyme disease rash to oral treatment with one of two antibiotics: amoxicillin or azithromycin. Twenty days later, 88% of patients receiving amoxicillin had experienced complete resolution of the rash and relief of 75% or more of accompanying symptoms versus 76% of patients taking azithromycin. All patients taking amoxicillin improved whereas three patients taking azithromycin either did not respond or got worse. Four percent of the amoxicillin group experienced a relapse within 180 days versus 16% of the azithromycin group. Twenty-four percent of the amoxicillin group reported side-effects versus 35% of the azithromycin group. Diarrhea was more common in the azithromycin group. Skin rash led six patients taking amoxicillin to stop therapy.

Objective: To compare the economic consequences of doxycycline therapy with those of azithromycin therapy for women with uncomplicated cervical chlamydial infections. Design: Decision analysis in which the health outcomes, costs, and cost-effectiveness of two provider-administered treatment strategies for women with uncomplicated cervical chlamydial infections were compared: 1) initial therapy with doxycycline, 100 mg orally twice daily for 7 days (estimated cost, $5.51) and 2) initial therapy with azithromycin, 1 g orally administered as a single dose (estimated cost, $18.75). Results: Under baseline assumptions, the azithromycin strategy incurred fewer major and minor complications and was less expensive overall than the doxycycline strategy despite a higher initial cost for acquiring antibiotic agents. In univariate sensitivity analyses, the azithromycin strategy prevented more major complications but was more expensive than the doxycycline strategy when doxycycline effectiveness was greater than 0.93. In a multivariate sensitivity analysis combining 11 parameter estimates selected so that the cost-effectiveness of the doxycycline strategy would be maximized relative to that of the azithromycin strategy, the azithromycin strategy resulted in fewer complications but was more costly. The incremental cost-effectiveness was $521 per additional major complication prevented. However, if the difference in the cost of azithromycin and doxycycline decreased to $9.80, the azithromycin strategy was less expensive and more effective, even under these extreme conditions. Conclusions: On the basis of the best available data as derived from the literature and experts, the azithromycin strategy was more cost-effective than the doxycycline strategy for women with uncomplicated cervical chlamydial infections. Despite the dominance of the azithromycin strategy over the doxycycline strategy, the adoption of the azithromycin strategy may be limited by the practical financial constraints of our currently fragmented health care system, in which the costs and benefits of preventing ch lamydia sequelae are often incurred by different components of the system.

Background and Objectives: Chancroid is endemic in sub-Saharan Africa and enhances the sexual transmission of the human immunodeficiency virus Type 1 (HIV-1). Azithromycin is an orally absorbed macrolide antibiotic that is active against Haemophilus ducreyi, the causative agent of chancroid, and has pharmacokinetic properties that are suitable for single dosing. Study Design: In a randomized single-blinded study of 127 men presenting to a referral STD clinic with culture proven chancroid, we compared the efficacy of azithromycin, administered as a single 1 g dose, with erythromycin 500 mg given 4 times daily for 7 days. Results: Cure rates were 89% (73 of 82) in the azithromycin group and 91% (41 of 45) in the erythromycin group. A failure to respond to treatment was associated with HIV-1 seropositivity and a lack of circumcision. Both regimens were well tolerated. Conclusions: Azithromycin, given as a single 1 g oral dose, is an effective treatment for chancroid in men, and offers major prescribing advantages over erythromycin., A single oral dose of azithromycin may be as effective as a seven-day course of erythromycin in curing chancroid. Chancroid is an ulcerative veneral disease that is endemic in sub-Saharan Africa. In a Nairobi clinic, 127 men with chancroid were randomly assigned to one treatment regimen or the other. Eighty-nine percent of those given azithromycin were cured compared with 91% of those given erythromycin. Lack of cure was associated with HIV-1 infection. The single-dose oral azithromycin treatment offers advantages in ease of administration and ensuring compliance. Reduction in ulcerative veneral disease is a major strategy in attempts to reduce HIV infection in Africa.

Background and Objectives: Azithromycin is a new, long-acting azalide antibiotic that is active against Neisseria gonorrhoeae. A single oral dose of 1.0 g is effective against uncomplicated genital infection with Chlamydia trachomatis. Goal of this Study: To compare the efficacy and tolerance of single-dose treatment of uncomplicated gonorrhea with azithromycin, 2.0 g orally, and ceftriaxone, 250 mg intramuscularly. Study Design: Seven hundred twenty-four men and women with presumptive, uncomplicated gonorrhea were treated with azithromycin 2.0 g orally or ceftriaxone 250 mg intramuscularly in a 2:1 ratio in a multicenter, open, randomized control trial in 10 public sexually transmitted disease clinics in the United States. Patients were followed up in 5 to 9 days and, for a subset of patients, 12 to 18 days after treatment. The main outcome measures were the isolation of N. gonorrhoeae and C. trachomatis and patient-reported side effects. Results. Among infected patients who returned for follow-up, N. gonorrhoeae was eradicated from all anatomic sites in 370 of 374 (98.9%; 95% confidence interval [95%CI] 97.9%-100%) treated with azithromycin and 171 of 175 (97.7%; 95%CI 95.5%-99.9%) given ceftriaxone. Treatment with either drug was effective in all 73 patients infected with [beta]-lactamase-producing N. gonorrhoeae. Chlamydial infection was eradicated in all 17 patients given azithromycin who returned and were recultured at follow-up and in two of seven patients given ceftriaxone (P < 0.001). Gastrointestinal side effects occurred in 35.3% (95%CI 30.7%-39.8%) of patients given azithromycin; of those, Azithromycin, a new antibiotic related to erythromycin, appears to be highly effective against gonorrhea. However, it also is very expensive at $50 per dose and causes gastrointestinal side effects more often than other antibiotics. Of the 549 men and women with confirmed diagnoses of gonorrhea enrolled in a study, 374 took two grams of azithromycin by mouth and 175 received an injection of 250 milligrams of another antibiotic, ceftriaxone. They were followed up within nine days of treatment. Ninety-nine percent of those in the azithromycin group and 98% of those treated with ceftriaxone were considered cured of gonorrhea at the first follow-up visit. A subset of 213 of the azithromycin patients was seen again two weeks after being treated. All of this group still tested negative as did 99% of the 81 in the ceftriaxone group who returned in two weeks. Thirty-five percent of those treated with azithromycin complained of nausea, vomiting and diarrhea. Only 2.4% of the ceftriaxone group reported such negative side effects.

Background and Objectives: Single dose regimens have advantages in the treatment of STD. Azithromycin has unique pharmacokinetics that may make single dose regimens feasible. Treatment with a single 1 g dose of azithromycin was compared to 100 mg doxycycline twice daily for seven days. Study Design: This was a randomized third-party blinded study on 183 male patients, 176 of whom could be evaluated for efficacy. Results: Chlamydia trachomatis was cultured from 148 patients, 79 receiving azithromycin and 69 receiving doxycycline. Six patients receiving azithromycin had positive cultures on follow-up, four were known to have had sexual intercourse with infected partners. Fifty-one patients had gonorrhea; 28 were treated with azithromycin and 23 with doxycycline. Neisseria gonorrhoeae was eradicated from all patients except one receiving azithromycin. He denied sexual exposure during follow-up. Sixty patients were infected with Ureaplasma urealyticum, 35 were treated with azithromycin and 25 with doxycycline. Five patients in each group had positive cultures on follow up. Three patients receiving azithromycin and two receiving doxycycline were known to have had sexual exposure during follow-up. Conclusion: A single dose of azithromycin showed similar effectiveness as a 7-day regimen of doxycycline., A single dose of the antibiotic azithromycin appears effective in treating several sexually transmitted diseases (STDs). Male patients at an STD clinic were randomly assigned to treatment with either 100 milligrams of doxycycline twice each day for seven days or a single 1 gram dose of azithromycin. Seventy-nine patients infected with Chlamydia trachomatis, 28 patients with gonorrhea and 35 patients infected with Ureaplasma urealyticum (U. urealyticum) took the single dose of azithromycin. Sixty-nine men with a chlamydia infection, 23 with gonorrhea and 25 infected with U. urealyticum took doxycycline. Of the patients with chlamydia, six patients who took azithromycin tested positive at a follow-up visit. Four of these patients had sexual contact with an infected partner. Of those with gonorrhea, one patient treated with azithromycin tested positive at a follow-up visit. He denied any sexual contact. Of those infected with U. urealyticum, five patients who took azithromycin and five who took doxycycline tested positive at follow-up. Three of those taking azithromycin and two of those who took doxycycline had sexual contact with infected partners.

Clarithromycin and azithromycin are among the new generation of macrolides that have recently been approved for use. Compared with currently available antibiotics, these agents may be given less frequently and, in the case of azithromycin, for a shorter duration. In vitro data suggest an antimi advantage of both clarithromycin and azithromycin against atypical mycobacterial and toxoplasmal species and possibly Haemophilus influenzae. The cost of both these agents is substantially higher than that of erythromycin and doxycycline, although the convenience of single-dose azithromycin is appealing compared with a 7-day course of doxycycline for chlamydial urethritis and cervicitis. Thes agents appear to offer advantages over erythromycin in the treatment of Mycobacterium avium-intracel Additional data are needed to establish their role in other bacterial infections., (Kanatani MS, Guglielmo BJ: The new macrolides--Azithromycin and clarithromycin. West J Med 1994; Erythromycin has been widely used in the treatment of pneumonias, including those caused by atypical organisms such [...]

PURPOSE: To compare the safety and efficacy of azithromycin, amoxicillin/probenecid, and doxycycline for the treatment of early Lyme disease, to identify risk factors for treatment failure, and to describe the serologic response in treated patients. PATIENTS AND METHODS: Fifty-five patients with erythema migrans and two patients with flu-like symptoms alone and fourfold changes in antibody titers to Borrelia burgdorferi were randomized to receive (1) oral azithromycin, 500 mg on the first day followed by 250 mg once a day for 4 days; (2) oral amoxicillin 500 mg and probenecid 500 mg, three times a day of each for 10 days; or (3) doxycycline, 100 mg twice a day for 10 days. If symptoms were still present at 10 days, treatment was extended with amoxicillin/probenecid or doxycycline for 10 more days. Evaluations were done at study entry and 10, 30, and 180 days later. RESULTS: Three of the patients who initially had symptoms suggestive of spread of the spirochete to the nervous system, one from each antibiotic treatment group, subsequently developed neurologic abnormalities, but symptoms in the other 54 patients resolved within 3 to 30 days after study entry. Six of the 19 patients (32%) (95% confidence interval, 13% to 57%) given amoxicillin/probenecid developed a drug eruption, whereas none of the patients given azithromycin or doxycycline had this complication. The presence of dysesthesias at study entry was the only risk factor significantly associated with treatment failure (p

This study was carried out to evaluate the effectiveness and safety of a newly developed antibiotic, azithromycin, for treating infections of the skin or skin structures (for instance, the connective tissue of the skin). One hundred forty-eight patients at 25 medical centers with abscesses, cellulitis (infection of the connective tissue), impetigo, infected wounds, or other infections were randomly assigned to receive either azithromycin (102 subjects) or cephalexin, a cephalosporin antibiotic, (46 subjects). Patients' clinical responses were determined by examination at baseline, and again on days 6, 11, 18, and 30 after treatment commencement. Bacteriologic eradication was defined as elimination of the causative organism by day 11 of the study. Results for the azithromycin group showed that clinical cures were effected after five days for 68 patients (67 percent), with 33 patients showing improvement. In the cephalexin group, 27 patients (59 percent) were cured after 10 days treatment, and 17 improved. The side effects of both drugs were mild and consisted of diarrhea, abdominal pain, and nausea. A five-day, once-daily course of azithromycin seems as effective as a 10-day, twice-daily course of cephalexin for managing skin and skin structure infections. (Consumer Summary produced by Reliance Medical Information, Inc.)

The effectiveness of a newly developed antibiotic, azithromycin, was evaluated for treating lower respiratory tract infections (LRTIs), such as bronchitis and pneumonia, in 272 patients at 26 medical centers. This drug is a member of the azalide group of antibiotics, and offers several advantages over erythromycin (used for treating some lung infections), including fewer side effects, greater stability in the stomach, a longer half-life, and high concentrations in body tissues, particularly the lung. Patients in the study were evaluated using clinical, laboratory, and radiographic tests, and by bacteriologic analysis of sputum. They were randomly assigned to receive either azithromycin (191 patients) or cefaclor, a cephalosporin active against many typical respiratory tract pathogens, (81 patients), and were evaluated on days 6, 11, 18, and 30. The proportion of patients cured or improved was high in both groups: 96.3 percent in the azithromycin group and 95.1 percent in the cefaclor group. The cure rate according to bacteriologic results (eradication of the causative organism) was 88.2 percent for azithromycin patients and 87.9 percent for cefaclor patients. Azithromycin was more effective (94.5 percent) than cefaclor (61.1 percent) against Haemophilus influenzae. A similar proportion of patients in the two groups reported side effects from their therapy, but most side effects were mild. The results indicate that a five-day course of once-daily azithromycin is as effective as a 10-day course of three times-daily cefaclor for treating LRTIs, a common, but potentially life-threatening condition. (Consumer Summary produced by Reliance Medical Information, Inc.)

Infection with Chlamydia trachomatis, a sexually transmitted organism, can lead to ectopic pregnancy (pregnancy located in a site other than the uterus) or infertility, and causes inflammation of the urethra in both sexes, and inflammation of the cervix in women. Although drugs such as tetracycline, doxycycline, erythromycin, and other agents are effective against Chlamydia trachomatis, they must be taken at least twice daily for seven days. Patients, particularly those without symptoms, often fail to take a full course of medication, and infections may persist. The effectiveness of azithromycin, one of a newly developed group of antibiotics called azalides, against Chlamydia trachomatis was evaluated in this article. Because azithromycin enters tissues readily, and becomes highly concentrated there, shorter durations of treatment are likely to be effective than with other drugs having poorer tissue penetration. To determine the optimal dose, it will be necessary to learn how long the drug remains in genital epithelial cells, the site of chlamydial infections. Research evidence suggests that a single dose of azithromycin is effective against uncomplicated chlamydial infections. Studies supporting this viewpoint are described. In one study, a single dose of azithromycin was more effective than seven days of ciprofloxacin; no significant side effects were reported with either drug. Since noncompliance with drug therapy is an important problem in treating chlamydial infections, a single-dose drug such as azithromycin offers considerable hope for improved cure rates. (Consumer Summary produced by Reliance Medical Information, Inc.)

Streptococcal pharyngitis (sore throat due to infection by streptococci) due to infection by group A beta-hemolytic streptococci (GABHS) can be treated with penicillin. However, many patients are allergic to this drug, and the infection sometimes remains even after treatment is over. To evaluate the effectiveness of azithromycin, a newly developed azalide antibiotic, a study was carried out of 242 patients with GABHS at 29 medical centers. The patients were randomly assigned to receive either azithromycin (151) or penicillin V (90): those in the azithromycin group took the drug once daily for five days, and those in the penicillin group took their drug every six hours for 10 days. They returned for follow-up clinic visits and additional throat cultures were taken on days 6, 11, 18, and 30 after drug therapy began. Results showed that all patients with one exception in each group were clinically cured or improved. Approximately 87 percent (131 patients) of the azithromycin group and 78 percent (70 patients) of the penicillin group were cured. GABHS was eradicated in 91 percent and 96 percent of the azithromycin and penicillin treated patients, respectively. When the infection recurred, clinical signs, such as sore throat and fever, were present in 3 of 13 azithromycin patients, and in 7 of 10 penicillin patients. Most side effects (diarrhea, nausea, and abdominal pain) were mild or moderate, but the azithromycin group had a higher frequency of these effects. Overall, azithromycin and penicillin V were comparable both clinically and bacteriologically. Larger studies should be carried out to investigate the effectiveness of both drugs against GABHS. (Consumer Summary produced by Reliance Medical Information, Inc.)

A study was carried out at 13 medical centers to compare the effectiveness of azithromycin, a new azalide antibiotic, with that of amoxicillin for treating acute maxillary sinusitis (inflammation of the sinuses between the eyes and upper jaw). Seventy-eight patients were randomly assigned to receive either azithromycin (41 subjects) or amoxicillin (37 subjects): of these, 38 completed the study and were considered evaluable. The diagnosis of acute sinusitis was made when bacteria were identified in sinus fluid. After treatment started, patients were examined on days 6, 11, 18, and 30. Results showed a bacteriologic cure rate of 100 percent in both groups. Both treatment groups indicated only mild side effects, which were reported by 4.9 percent of the azithromycin patients and 8.1 percent of the amoxicillin patients. Azithromycin was given five times over a 5-day period, whereas 30 doses of amoxicillin were given over 10 days. The fact that the former drug was effective with fewer doses should improve patient compliance. Azithromycin seems to be a well-tolerated, effective drug for treating acute sinusitis. (Consumer Summary produced by Reliance Medical Information, Inc.)

The activity of azithromycin, an azalide drug with several properties that make it preferable to erythromycin in many clinical situations, against specific microorganisms is reviewed. The minimum inhibitory concentrations of the drug needed to check the growth of both Gram-positive and Gram-negative bacteria (a classification system based on the organism's response to the Gram stain) are listed. It is active against Haemophilus influenzae, against which erythromycin is inactive. Azithromycin is also effective against certain intracellular pathogens such as Chlamydia trachomatis (which causes genital chlamydia infections) and Legionella species. Results from experiments with animal models of infection indicate that high tissue levels of the drug may be effective even when blood levels are below the levels thought to be necessary for effectiveness. Some of these results are summarized. Azithromycin acts by inhibiting bacterial protein synthesis at the 50S ribosomal level. Because its movement into tissues is rapid and its concentration in tissues is high, measurement of blood levels of the drug is not a useful indicator of overall concentration in the body. Much remains to be learned concerning the clinical effectiveness of azithromycin. (Consumer Summary produced by Reliance Medical Information, Inc.)

This introduction to a symposium concerning azithromycin reviews the pharmacokinetic basis for antimicrobial therapy, with particular emphasis on the actions, effectiveness, and limitations of treatment with macrolide antibiotics (such as erythromycin) and azalides (such as azithromycin). An ideal antimicrobial drug should: be effective against a range of bacteria; have selective toxicity for microbes; not induce drug resistance; have no or minimal side effects; be available in both oral, injectable, and infusible form; and require infrequent dosing. Erythromycin, while widely used and effective in many instances, is associated with gastrointestinal side effects, has a rather narrow range of activity, and has certain other limitations. The use of many macrolides is limited by the fact that they are not stable under acidic conditions, such as those in the stomach, and are poorly absorbed when given orally. However, newer agents are more resistant to acid: some of these are roxithromycin, clarithromycin, and dirithromycin. Azithromycin is active against many Gram-positive and some Gram-negative bacteria (a classification system based on the microorganism's response to the Gram stain). It penetrates well into tissues and transported by certain white blood cells, which deliver the drug to the infected site. This means that the standard way of estimating antimicrobial effectiveness, the measurement of blood levels of the drug, is not meaningful for such a drug. Most organisms that are resistant to erythromycin are also resistant to other macrolides and to azalides. Macrolides can be inactivated by enzymes present in bacteria. Azithromycin seems to be the first antibiotic that is effective against genital chlamydial infections with just one dose, and also appears effective against group A streptococcal pharyngitis after only a five-day course. Several problems remain to be solved concerning this drug, including its effects in patients with bacteremia (bacteria in the bloodstream), its activity in sites with low pH (such as abscesses), and its potential to induce resistance. (Consumer Summary produced by Reliance Medical Information, Inc.)

Azithromycin is an effective, single-drug therapy for mild-to-moderate community-acquired pneumonia., TO DETERMINE WHETHER AZITHROMYCIN ALONE (without an additional [beta]-lactam antibacterial agent) is an effective treatment for patients with mild-to-moderately severe community-acquired pneumonia, Feldman and associates performed this retrospective cohort study [...]

Chlamydia trachomatis is a very common sexually-transmitted bacteria, causing an estimated 4 million infections each year. Infection with C. trachomatis can cause inflammation of the genital tract, urethritis (inflammation of the urethra), infertility, premature birth, and ectopic pregnancy (development of the fetus outside of the uterus). The standard treatment recommended by the Centers for Disease Control for chlamydial infection is oral doxycycline (100 milligrams, two times a day for seven days) or oral tetracycline (500 milligrams, four times a day for seven days). Since treatment with these antibiotics requires multiple doses taken over a one-week-period, patient compliance can be a problem. A relatively new antibiotic called azithromycin was developed with the hope that a single dose could be effective in treating chlamydial infections. Several studies have been performed to compare the effectiveness of azithromycin with doxycycline. These studies found that a single dose of azithromycin (1 gram, given once) was as effective as 14 doses of doxycycline (100 milligrams, two times a day for seven days) in treating patients with chlamydial infections. Both drug treatments cured infections in 92 percent of the patients after one week, and cured 95 percent in two weeks. Both drugs caused mild gastrointestinal side effects. It is concluded that a single dose of azithromycin provides a safe and effective treatment for chlamydial infections. (Consumer Summary produced by Reliance Medical Information, Inc.)