The comparative efficacy and safety of clarithromycin and amoxycillin in the treatment of outpatients with acute maxillary sinusitis

Yamik Sinus Catheter in the Topical Treatment of Patients with Acute Rhinosinusitis after Previous Sinus Surgery

Background

The Yamik sinus catheter was designed as a new device for the topical treatment of rhinosinusitis. It creates intermittent positive and negative intranasal pressure after sealing the ipsilateral nostril and choana with two inflatable cuffs. Affecting the nasal cavity and all paranasal sinuses of one side at a time, it is used to evacuate mucous and secretions as well as and to introduce antiseptic, antibacterial, or antifungal solutions.

Methods

This study was designed to evaluate the effectiveness of the Yamik catheter in cases of acute purulent rhinosinusitis in patients who previously underwent endonasal sinus surgery for chronic rhinosinusitis. Twenty patients were treated at repeated visits to the outpatient clinic of our institution. At each visit, their clinical symptoms as well as findings on anterior rhinoscopy, nasal endoscopy, and A-mode ultrasound were evaluated.

Results

Acute disease resolved completely within 10 days of treatment in 17 of the 20 patients. Two patients discontinued treatment after repeated visits, showing only mild improvement. One patient felt uncomfortable during the application of the Yamik catheter and did not continue after the initial treatment.

Conclusion

Our results suggest that the Yamik catheter may be a helpful device in the topical treatment of acute rhinosinusitis and it appears possibly helpful in patients who suffer from episodes of acute purulent infection after previous sinus surgery.

Clinical Course of Acute Maxillary Sinusitis Documented by Sequential MRI Scanning

A prospective study was designed to assess clinical and mucosal changes that occur during resolution of acute maxillary sinusitis. Thirteen previously healthy subjects with symptoms of acute sinusitis and radiographic opacification of at least one maxillary sinus were entered into the study and treated with amoxicillin/clavulinate potassium. Assessment of clinical symptoms, clinical examination, and magnetic resonance imaging (MRI) of the maxillary sinuses were performed at baseline and at days 3, 7, 10, 14, 21, 28 and 56 after initiation of therapy. The T2 values from the MRI scans were analyzed to approximate the more viscous and more fluid-like components of the maxillary sinus contents. After three days of antibiotic therapy, there was marked improvement in facial tenderness, thickness of nasal discharge, volume of nasal discharge, headache, and nasal congestion. Ten to 14 days of treatment were required, however, for improvement in nasal patency. MRI analysis of the volume percentage of air in the involved sinuses showed that by 10 days, only half of the opacification (fluid and thickened mucosa) had resolved. By 56 days, the sinuses were only about 80% aerated. This improvement was attributed mainly to resolution of the more fluid-like component. This study shows that: (1) tissue/fluid changes in sinusitis can be followed with MRI, and (2) although treatment of acute maxillary sinusitis generally results in clinical resolution of symptoms within one week, mucosal changes can persist for 8 weeks or more.

Management of Acute and Chronic Sinusitis in Adult Patients

Sinusitis is a highly prevalent illness in the United States resulting in significant sinus discomfort and pain. Diagnoses of sinusitis are typically based on patients’clinical presentations but are complicated because numerous microbiologic etiologies exist (viruses, bacteria, fungi). Along with its diagnosis, sinusitis should be classified as acute or chronic on the basis of the duration of symptoms. It is important to differentiate acute from chronic sinusitis because their etiologies and treatments may differ. Patients who present with symptoms of acute sinusitis for at least 1 week after an acute viral illness are appropriate candidates for antibiotics. Antibiotic choices should be based on local resistance patterns and patients’ characteristics, but a 2-week course of first-line antibiotics (eg, amoxicillin, trimethoprim-sulfamethoxazole) is usually sufficient. Compared to that of acute sinusitis, the management of chronic bacterial sinusitis is more complicated and controversial. Chronic sinusitis may be medically or surgically managed. Medical therapy of chronic bacterial sinusitis should consist of a prolonged course of antibiotics (4 to 6 weeks). Broad-spectrum antibiotics should be used, covering Staphylococcus aureus, • -lactamase-producing organisms, and in certain situations anaerobes. Adjunctive therapy with saline nasal spray, nasal decongestants, and inhaled nasal corticosteroids may be helpful for certain patients with acute or chronic sinusitis.

WITHDRAWN: Antibiotics for acute maxillary sinusitis in adults

Currently, two separate Cochrane reviews, ‘Antibiotics for acute maxillary sinusitis in adults ’ and ‘Antibiotics for clinically diagnosed acute rhinosinusitis in adults ’ describe the effect of antibiotics for acute rhinosinusitis. Although both Cochrane reviews study the same condition, they look at different populations (patients in which the diagnosis was based on clinical signs and symptoms and patients in which the diagnosis was confirmed by imaging). Because of this, the conclusions are different in these Cochrane reviews. This was confusing for clinicians who needed to read both Cochrane reviews to know which conclusions are most applicable to their patients.
 
 This review is being withdrawn and will be incorporated into the updated publication of ‘Antibiotics for clinically diagnosed acute rhinosinusitis in adults ’. This ‘merged’ review will still maintain the relevant distinction between the two populations. However, information on the effectiveness of antibiotics for rhinosinusitis will be published in the ‘merged’ Cochrane review. We will omit the comparison between antibiotics (as published in this Cochrane review) because the choice for certain antibiotics and/or doses differs according to the local antibiotic resistance patterns and therefore this comparison is less relevant.

The editorial group responsible for this previously published document have withdrawn it from publication.

Antibiotics for acute maxillary sinusitis in adults

BACKGROUND

Sinusitis is one of the most common diagnoses among adults in ambulatory care, accounting for 15% to 21% of all adult outpatient antibiotic prescriptions. However, the role of antibiotics for sinusitis is controversial.

OBJECTIVES

To assess the effects of antibiotics in adults with acute maxillary sinusitis by comparing antibiotics with placebo, antibiotics from different classes and the side effects of different treatments.

SEARCH METHODS

We searched CENTRAL 2013, Issue 2, MEDLINE (1946 to March week 3, 2013), EMBASE (1974 to March 2013), SIGLE (OpenSIGLE, later OpenGrey (accessed 15 January 2013)), reference lists of the identified trials and systematic reviews of placebo-controlled studies. We also searched for ongoing trials via ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP). We imposed no language or publication restrictions.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing antibiotics with placebo or antibiotics from different classes for acute maxillary sinusitis in adults. We included trials with clinically diagnosed acute sinusitis, confirmed or not by imaging or bacterial culture.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened search results, extracted data and assessed trial quality. We calculated risk ratios (RRs) for differences between intervention and control groups in whether the treatment failed or not. All measures are presented with 95% confidence intervals (CIs). We conducted the meta-analyses using either the fixed-effect or random-effects model. In meta-analyses of the placebo-controlled studies, we combined data across antibiotic classes. Primary outcomes were clinical failure rates at 7 to 15 days and 16 to 60 days follow-up. We used GRADEpro to assess the quality of the evidence.

MAIN RESULTS

We included 63 studies in this updated review; nine placebo-controlled studies involving 1915 participants (seven of the studies clearly conducted in primary care settings) and 54 studies comparing different classes of antibiotics (10 different comparisons). Five studies at low risk of bias comparing penicillin or amoxicillin to placebo provided information on the main outcome: clinical failure rate at 7 to 15 days follow-up, defined as a lack of full recovery or improvement, for participants with symptoms lasting at least seven days. In these studies antibiotics decreased the risk of clinical failure (pooled RR of 0.66, 95% CI 0.47 to 0.94, 1084 participants randomised, 1058 evaluated, moderate quality evidence). However, the clinical benefit was small. Cure or improvement rates were high in both the placebo group (86%) and the antibiotic group (91%) in these five studies. When clinical failure was defined as a lack of full recovery (n = five studies), results were similar: antibiotics decreased the risk of failure (pooled RR of 0.73, 95% CI 0.63 to 0.85, high quality evidence) at 7 to 15 days follow-up.Adverse effects in seven of the nine placebo-controlled studies (comparing penicillin, amoxicillin, azithromycin or moxicillin to placebo) were more common in antibiotic than in placebo groups (median of difference between groups 10.5%, range 2% to 23%). However, drop-outs due to adverse effects were rare in both groups: 1.5% in antibiotic groups and 1% in control groups.In the 10 head-to-head comparisons, none of the antibiotic preparations were superior to another. However, amoxicillin-clavulanate had significantly more drop-outs due to adverse effects than cephalosporins and macrolides.

AUTHORS' CONCLUSIONS

There is moderate evidence that antibiotics provide a small benefit for clinical outcomes in immunocompetent primary care patients with uncomplicated acute sinusitis. However, about 80% of participants treated without antibiotics improved within two weeks. Clinicians need to weigh the small benefits of antibiotic treatment against the potential for adverse effects at both the individual and general population levels.

The use of macrolides in respiratory tract infections

Macrolides have enjoyed continued use for over 40 years, being increasingly usedfor the treatment of respiratory tract infections. Newer macrolides have been introduced that show improved absorption after oral administration, better gastrointestinal tolerance, and delivery of increased amounts of drug to the infection site. Macrolides are commonly used in community-acquired pneumonia, as well as in atypical pneumonia and legionellosis. The newer macrolides, in comparative studies, have been shown to be as effective as the conventional therapies for treating acute otitis media, acute sinusitis and acute pharyngitis, with a low incidence of side-effects. However, dosing can be simplified because of their unique pharmacokinetic properties. Limitations in the use of macrolides for respiratory infections include rather marginal activity in the most severe cases of Haemophilus influenzae infections, lack of activity against Klebsiella and other coliforms, which precludes their use as single agents in the therapy of pneumonia in patients with significant underlying disease or in the elderly, and development of resistance in streptococci and staphylococci.

Azithromycin extended release vs amoxicillin/clavulanate: symptom resolution in acute sinusitis

OBJECTIVE

The aim of the study was to compare early symptom resolution with a single 2-g dose of azithromycin extended release or 10 days of amoxicillin/clavulanate 875 mg/125 mg every 12 hours in patients with acute sinusitis.

MATERIALS AND METHODS

This was a prospective, randomized, open-label, observational study to mimic "real-world" conditions, including patients with symptoms of acute bacterial sinusitis lasting between 7 and 30 days. Key symptoms were assessed twice daily by patient diary, and patients were interviewed by telephone at 12 and 28 days. The primary end point was symptom resolution at 5 days, defined as reporting "no problem" with at least 3 of 4 diary symptoms in 2 consecutive measures in the per-protocol population. Secondary end points included additional antibiotic use, sinusitis-related quality of life, and treatment satisfaction.

RESULTS

Three hundred seventy-eight patients were randomized to a single dose of azithromycin extended release and 371 to 10 days of amoxicillin/clavulanate. In the per-protocol population at day 5, 70/236 patients (29.7%) in the azithromycin extended release arm and 45/238 patients (18.9%) in the amoxicillin/clavulanate arm had resolution of symptoms (difference = 10.8%; 95% confidence interval [CI], 3.1-18.4%). By day 28, 26/236 patients (11.0%) in the azithromycin extended release arm and 27/238 patients (11.3%) in the amoxicillin/clavulanate arm had used additional antibiotics (difference = -0.4%; 95% CI: -6.1% to 5.3%). Additional physician visits, quality of life, and overall satisfaction were similar between groups.

CONCLUSIONS

More patients randomized to azithromycin extended release experienced symptom resolution at day 5 than those randomized to amoxicillin/clavulanate, without experiencing differences in second antibiotic use at 28 days.

Clinical efficacy and time to symptom resolution of 5-day telithromycin versus 10-day amoxicillin-clavulanate in the treatment of acute bacterial sinusitis

OBJECTIVE

This study compared the clinical efficacy, time to symptom resolution, and tolerability of a 5-day regimen of telithromycin with a 10-day regimen of high-dose amoxicillin-clavulanate in acute bacterial sinusitis (ABS).

RESEARCH DESIGN AND METHODS

In this multinational (41 centers in Canada, Germany, Greece, Portugal, and Turkey), open-label, noninferiority study, patients >/=18 years old (n=298) with a clinical (>7 days' symptoms) and radiological (air/fluid level, total opacification, mucosal thickening >/=10 mm) diagnosis of ABS were randomized to receive telithromycin 800 mg once daily for 5 days or amoxicillin-clavulanate 875/125 mg twice daily for 10 days. Clinical efficacy and tolerability were assessed at the test-of-cure visit (days 17-21). Time to symptom resolution was based on patients' daily diary assessment of individual symptoms.

RESULTS

The per-protocol clinical success rate (primary endpoint) with telithromycin (88.6% (109/123)) was noninferior to that with amoxicillin-clavulanate (88.8% (111/125)) (95% confidence interval: -8.9 to 8.5). In the modified intention-to-treat (mITT) population, the median time for 50% reduction of total symptom scores was significantly shorter for telithromycin (4 days) vs. amoxicillin-clavulanate (5 days; p=0.044); median times for 75% reduction of total symptom scores were: telithromycin, 7 days; amoxicillin-clavulanate, 8 days (p=0.115). The median time for reduction of total symptom scores to the absent/very mild category (mITT population) was 6 days for telithromycin vs. 8 days for amoxicillin-clavulanate (p=0.04). All treatment-emergent adverse events (TEAEs) were mostly gastrointestinal and occurred in 20.7% (30/145) of telithromycin-treated patients vs. 31.8% (47/148) of amoxicillin-clavulanate-treated patients (p=0.034). One serious AE was reported in the telithromycin group, but it was considered not to be related to treatment.

CONCLUSIONS

This open-label, randomized study demonstrated that treatment of ABS with telithromycin resulted in comparable clinical efficacy, shorter times to symptom resolution, and fewer total TEAEs than treatment with amoxicillin-clavulanate.

Antibiotics for acute maxillary sinusitis

BACKGROUND

Expert opinions vary on the appropriate role of antibiotics for sinusitis, one of the most commonly diagnosed conditions among adults in ambulatory care.

OBJECTIVES

We examined whether antibiotics are effective in treating acute sinusitis, and if so, which antibiotic classes are the most effective.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2007, Issue 3); MEDLINE (1950 to May 2007) and EMBASE (1974 to June 2007).

SELECTION CRITERIA

Randomized controlled trials (RCTs) comparing antibiotics with placebo or antibiotics from different classes for acute maxillary sinusitis in adults. We included trials with clinically diagnosed acute sinusitis, whether or not confirmed by radiography or bacterial culture.

DATA COLLECTION AND ANALYSIS

At least two review authors independently screened search results, extracted data and quality assessed trials. Risk ratios (RR) were calculated for differences in the intervention and control groups to see whether or not the treatment was a failure. In meta-analysing the placebo-controlled studies, the data across antibiotic classes were combined. Primary outcomes were the clinical failure rates at 7 to 15 days and 16 to 60 days follow up.

MAIN RESULTS

Fifty-seven studies were included in the review; six placebo-controlled studies and 51 studies comparing different classes of antibiotics. Five studies involving 631 participants provided data for comparison of antibiotics to placebo, when clinical failure was defined as a lack of cure or improvement at 7 to 15 days follow up. These studies found a slight statistical difference in favor of antibiotics, compared to placebo, with a pooled RR of 0.66 (95% confidence interval (CI) 0.44 to 0.98). However, the clinical significance of the result is equivocal, also considering that cure or improvement rate was high in both the placebo group (80%) and the antibiotic group (90%). Based on six studies, when clinical failure was defined as a lack of total cure, there was significant difference in favor of antibiotics compared to placebo with a pooled RR of 0.74 (95% CI 0.65 to 0.84) at 7 to 15 days follow up. None of the antibiotic preparations was superior to each other.

AUTHORS' CONCLUSIONS

Antibiotics have a small treatment effect in patients with uncomplicated acute sinusitis in a primary care setting with symptoms for more than seven days. However, 80% of participants treated without antibiotics improve within two weeks. Clinicians need to weigh the small benefits of antibiotic treatment against the potential for adverse effects at both the individual and general population level.

Staphylococcus aureus is a major pathogen in acute bacterial rhinosinusitis: a meta-analysis

BACKGROUND

Acute bacterial rhinosinusitis is a common health problem in the United States. Appropriate recommendations for the treatment of acute bacterial rhinosinusitis are based on the prevalence and expected antimicrobial susceptibilities of specific pathogens.

METHODS

A meta-analysis was performed on the English language literature from the period 1990-2006, including prospective studies of antibiotic therapy for acute bacterial rhinosinusitis for which sinus cultures were required in the form of either maxillary sinus taps or middle meatal cultures. Weighted mean culture rates for Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Staphylococcus aureus were abstracted from the included articles and compared according to culture technique.

RESULTS

Culture rates (i.e., the percentage of patients with positive culture results) were 32.7% for S. pneumoniae, 31.6% for H. influenzae, 10.1% for S. aureus, and 8.8% for M. catarrhalis. No statistically significant difference was seen between the culture rates for S. aureus and M. catarrhalis. Analysis of the effect of culture technique on the culture rates revealed no statistically significant difference.

CONCLUSIONS

The prevalence of S. aureus among sinus cultures warrants its reconsideration as a major pathogen in acute bacterial rhinosinusitis. As a result, increasing trends of drug-resistant strains may complicate antibiotic recommendations.

Antibiotics for acute maxillary sinusitis

BACKGROUND

For adults seeking care in ambulatory medical practices, sinusitis is the most common diagnosis treated with antibiotics.

OBJECTIVES

We examined whether antibiotics are indicated for acute sinusitis, and if so, which antibiotic classes are most effective.

SEARCH STRATEGY

Relevant studies were identified from searches of MEDLINE and EMBASE in December 2001, contacts with pharmaceutical companies and bibliographies of included studies.

SELECTION CRITERIA

Randomized trials were eligible that compared antibiotic to control or antibiotics from different classes, for acute maxillary sinusitis. Additional criteria for inclusion were diagnostic confirmation by radiograph or sinus aspiration, outcomes that included clinical cure or improvement, and a sample size of 30 or more adults. Of 2058 potentially relevant studies, two or more reviewers identified 49 studies meeting selection criteria.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two persons and synthesized descriptively. Some data were analyzed quantitatively using a random effects model. Primary outcomes were: a) clinical cure, and b) clinical cure or improvement. Secondary outcomes were radiographic improvement, relapse rates, and dropouts due to adverse effects.

MAIN RESULTS

Forty-nine trials, involving 13,660 participants, evaluated antibiotic treatment for acute maxillary sinusitis. Major comparisons were antibiotic versus control (n of 5); newer, non-penicillin antibiotic versus penicillin class (n of 10); and amoxicillin-clavulanate versus other extended spectrum antibiotics (n of 17), where n is the number of trials. Most trials were conducted in otolaryngology settings. Only 8 trials described adequate allocation and concealment procedures; 20 were double-blind. Compared to control, penicillin improved clinical cures [relative risk (RR) 1.72; 95% CI 1.00 to 2.96]. Treatment with amoxicillin did not significantly improve cure rates (RR 2.06; 95% CI 0.65 to 6.53) but there was significant variability between studies. Radiographic outcomes were improved by antibiotic treatment. Comparisons between classes of antibiotics showed no significant differences: newer non-penicillins versus penicillins (RR for cure 1.07; 95% CI 0.99 to 1.17); newer non-penicillins versus amoxicillin-clavulanate (RR for cure 1.03; 95% CI 0.96 to 1.11). Compared to amoxicillin-clavulanate, dropouts due to adverse effects were significantly lower for cephalosporin antibiotics (RR 0.47; 95% CI 0.30 to 0.73). Relapse rates within one month of successful therapy were 7.7%.

REVIEWER'S CONCLUSIONS

For acute maxillary sinusitis confirmed radiographically or by aspiration, current evidence is limited but supports the use of penicillin or amoxicillin for 7 to 14 days. Clinicians should weigh the moderate benefits of antibiotic treatment against the potential for adverse effects.

Postmarketing surveillance of medications and pregnancy outcomes: clarithromycin and birth malformations

PURPOSE

This retrospective surveillance study used linked administrative claims data and medical records to determine the rate and types of birth malformations in infants born to women exposed to the antibiotic, clarithromycin (Biaxin), during the first trimester of pregnancy.

METHODS

Pharmacy and hospital claims from eight geographically diverse health plans were used to identify women who had a delivery claim within 270 days of a clarithromycin prescription over a 5-year period (1991-1995). Hospital delivery admission medical records for 143 mothers and their 149 infants were abstracted to identify birth malformations.

RESULTS

Five infants were identified with major malformations, three with minor malformations, and four with undescended testicles likely to resolve with time. The observed rate of 3.4% (95% CI, 0.5, 6.3) for major malformations was not statistically significantly different compared to an expected rate of 2.8% based on earlier national data. There was no consistency across types of major malformations.

CONCLUSIONS

These results provide no evidence that clarithromycin is a likely major teratogen in humans. Use of claims data is one way to evaluate quickly and efficiently the safety of prescription medications in humans during pregnancy, especially when both exposure and outcome are rare.

Review and comparison of advanced-generation macrolides clarithromycin and dirithromycin

We reviewed English-language clinical studies, abstracts, and review articles identified from MEDLINE searches from January 1966-August 1998, and bibliographies of identified articles to compare advanced-generation macrolides dirithromycin and clarithromycin and their use for respiratory tract infections. Both agents have superior adverse effect profiles compared with erythromycin, the original macrolide. Both have broad antibacterial coverage, but clarithromycin usually has a lower MIC90 to susceptible organisms than dirithromycin; for most isolates this difference is not clinically significant. Clarithromycin has better in vitro coverage of Haemophilus influenzae, but this activity varies with formation of its bioactive metabolite, 14-hydroxyclarithromycin. Neither agent is ideal for H. influenzae eradication. The agents differ markedly in terms of pharmacokinetics, pharmacodynamics, metabolism, and cost, and thus with respect to drug interaction profiles and dosages. Dirithromycin's drug interaction profile is markedly better than clarithromycin's. Clarithromycin is dosed twice/day; dirithromycin's pharmacokinetics allow once/day dosing. Dirithromycin is less expensive with regard to both cost/day and cost/treatment regimen. Clarithromycin has been studied and approved for administration to children. In adults with respiratory tract infections who are receiving drugs that would interact with clarithromycin, and in those with renal dysfunction with or without coexisting hepatic dysfunction, dirithromycin appears to be superior in terms of safety and equivalent to clarithromycin in terms of efficacy.

Double-blind comparative trial of ciprofloxacin versus clarithromycin in the treatment of acute bacterial sinusitis. Sinusitis Infection Study Group

This multicenter, randomized, double-blind trial compared the efficacy and safety of ciprofloxacin (CIP; 500 mg twice daily for 10 days, placebo for 4 days) to those of clarithromycin (CLARI; 500 mg twice daily for 14 days) in 560 adults with clinically documented and radiologically confirmed acute sinusitis. Of 457 efficacy-valid adults (236 CIP, 221 CLARI), clinical resolution plus improvement at the end of therapy was 84% for CIP-treated patients compared to 91% of CLARI recipients (CI95 = -0.131, -0.013). At the 1-month follow-up, more than twice as many CLARI-treated patients, 18 (10%), experienced a relapse, compared to 7 (4%) CIP-treated patients. The combined clinical response analyses (end of therapy and 1 -month follow-up) demonstrated that CIP and CLARI were statistically equivalent (CI95 = -0.106, 0.044). Diarrhea, nausea, headache, and dizziness were the most frequently reported drug-related adverse events in both treatment groups; diarrhea and taste perversion were reported more frequently among CLARI recipients. In summary, the combined end of therapy and follow-up clinical evaluation analyses revealed that CIP and CLARI were equally effective in the management of acute sinusitis, although twice as many relapses were reported among CLARI recipients.

Comparison of sparfloxacin and clarithromycin in the treatment of acute bacterial maxillary sinusitis. Sparfloxacin Multicenter AMS Study Group

Five hundred four patients were enrolled in a randomized, double-masked, multicenter study comparing the efficacy and tolerability of a 10-day regimen of sparfloxacin with a 14-day regimen of clarithromycin in the treatment of acute maxillary sinusitis. Two hundred fifty-two patients received sparfloxacin as a single 400-mg dose on day 1 and 200 mg once daily for 9 additional days, and 252 patients received clarithromycin 500 mg twice daily for 14 days. In the all-treated population, clinical success was observed at 6 to 10 days after therapy in approximately 82% of the patients in each treatment group. A total of 430 patients met the inclusion criteria for clinical assessment. The success rates in these patients were also comparable, at 83.1% and 83.4% for the sparfloxacin and clarithromycin groups, respectively. Sustained clinical success rates in the all-treated population 3 to 4 weeks after therapy were 71.6% for the sparfloxacin group and 68.6% for the clarithromycin group. All treated patients were included in the tolerability analysis. The frequency of adverse events in the clarithromycin and sparfloxacin groups was 57.9% and 48.4%, respectively. The most frequently noted adverse events were diarrhea, photosensitivity reaction, taste perversion, nausea, and abdominal pain; >96% of adverse events in the sparfloxacin group and 94% of adverse events in the clarithromycin group were of mild or moderate severity. Among adverse events at least possibly related to study drug, photosensitivity reaction was more common in the sparfloxacin group (9.5% vs. 0.4%), whereas taste perversion (8.7% vs. 0.8%) and abdominal pain (3.6% vs. 1.6%) were more common in the clarithromycin group. Thus the sparfloxacin's more convenient regimen was as effective as clarithromycin in the treatment of acute bacterial maxillary sinusitis, and the overall frequency of adverse events with sparfloxacin was comparable to that with clarithromycin.

Azithromycin versus amoxicillin/clavulanate in the treatment of acute sinusitis

PURPOSE

To compare the efficacy and tolerability of a 3-day course of azithromycin with a 10-day course of amoxicillin/clavulanic acid in the treatment of acute sinusitis in adults.

PATIENTS AND METHODS

One hundred adult patients with acute sinusitis were included in an open, randomized study. Clinical diagnosis of sinusitis was confirmed by nasal endoscopy, sinus radiography, and (when possible) by culture of sinus aspirate. Patients were randomized to receive azithromycin (500 mg once daily for 3 days) or amoxicillin/clavulanate (625 mg every 8 hours for 10 days).

RESULTS

A significantly faster resolution of signs and symptoms of sinusitis was observed in the azithromycin-treated patients. By the end of therapy (days 10-12), 95% of the patients in the azithromycin group and 74% in the amoxicillin/clavulanate group were cured. The remaining patients' conditions were improved. By the follow-up visit, cure was achieved in 98% of the azithromycin-treated patients, and 91% of the amoxicillin/clavulanate-treated patients. Treatment failure was observed in three patients from the amoxicillin/clavulanate group, and relapse occurred in one patient from each group. Bacteriologic eradication was achieved in 23 of 23 and 21 of 24 patients treated with azithromycin and amoxicillin/clavulanate, respectively. Both drugs were well tolerated. Two patients (4%) from the azithromycin group and five patients (10%) from the amoxicillin/clavulanate group reported mild gastrointestinal disturbances.

CONCLUSIONS

In adults with acute sinusitis, a 3-day course of azithromycin was as effective and well tolerated as a 10-day course of amoxicillin/clavulanic acid. A significantly simpler dosage regimen and faster clinical effect were the advantages of azithromycin.

Efficacy and safety of oral levofloxacin compared with clarithromycin in the treatment of acute sinusitis in adults: a multicentre, double-blind, randomized study. The Canadian Sinusitis Study Group

Adult patients with acute sinusitis (n = 236) were randomized in a double-blind study to levofloxacin 500 mg orally once daily (n = 119) or clarithromycin 500 mg orally twice daily (n = 117) for 10-14 days. Between 2 and 5 days after therapy participants were evaluated as cured (no symptoms), improved (symptoms improved, no further therapy required), or failed (further therapy required). Clinical response rates (cured plus improved) for clinically evaluable patients were 93.9% for levofloxacin (n = 98) and 93.5% for clarithromycin (n = 93). The proportion of patients evaluated as cured was higher in the levofloxacin (40.8%) than in the clarithromycin arm (29.0%) and individual symptoms showed higher rates of resolution. Of patients receiving levofloxacin and clarithromycin, 22.5% and 39.3%, respectively, experienced adverse events related or possibly related to the study therapy. This study showed that, in the treatment of acute sinusitis, daily levofloxacin therapy is as effective as twice-daily clarithromycin therapy with more complete clearing of symptoms and a more tolerable side-effect profile.

Are amoxycillin and folate inhibitors as effective as other antibiotics for acute sinusitis? A meta-analysis

OBJECTIVES

To examine whether antibiotics are indicated in treating uncomplicated acute sinusitis and, if so, whether newer and more expensive antibiotics with broad spectra of antimicrobial activity are more effective than amoxycillin or folate inhibitors.

DESIGN

Meta-analysis of randomised trials.

SETTING

Outpatient clinics.

SUBJECTS

2717 patients with acute sinusitis or acute exacerbation of chronic sinusitis from 27 trials.

INTERVENTIONS

Any antibiotic versus placebo; amoxycillin or folate inhibitors versus newer, more expensive antibiotics.

MAIN OUTCOME MEASUREMENTS

Clinical failures and cures.

RESULTS

Compared with placebo, antibiotics decreased the incidence of clinical failures by half (risk ratio 0.54 (95% confidence interval 0.37 to 0.79)). Risk of clinical failure among 1553 randomised patients was not meaningfully decreased with more expensive antibiotics as compared with amoxycillin (risk ratio 0.86 (0.62 to 1.19); risk difference 0.9 fewer failures per 100 patients (1.4 more failures to 3.1 fewer failures per 100 patients)). The results were similar for other antibiotics versus folate inhibitors (risk ratio 1.01 (0.52 to 1.97)), but data were sparse (n=410) and of low quality.

CONCLUSIONS

Amoxycillin and folate inhibitors are essentially as effective as more expensive antibiotics for the initial treatment of uncomplicated acute sinusitis. Small differences in efficacy may exist, but are unlikely to be clinically important.

Oral cimetidine prolongs clarithromycin absorption

The present study was conducted to identify any potential interaction between oral cimetidine and clarithromycin. Twelve healthy subjects were administered single doses of clarithromycin alone and with oral cimetidine dosed to steady state. Cimetidine prolonged the absorption of clarithromycin, as evidenced by decreased peak concentrations of both clarithromycin and 14-OH-clarithromycin (14OHC) in serum (46 and 43%, respectively), a delay in the formation of 14OHC (increase of 68%), and increases in both of their half-lives (75 and 82%, respectively), despite no changes in total oral clearance or area under the concentration-time curve for either compound. No mechanism for this interaction has been identified.

Antimicrobial treatment in acute maxillary sinusitis: a meta-analysis

OBJECTIVE

The aims of this study were to assess which antibiotic is most effective in the treatment of acute maxillary sinusitis in otherwise healthy adults and adolescents, and which has the fewest side effects.

DESIGN

To assess the short-term effects of antimicrobial treatments, a meta-analysis was performed using Mantel-Haenszel procedures on 16 comparative, randomized studies with a total number of 3358 patients. No placebo-controlled studies were available. Antimicrobial treatments were categorized according to type, spectrum, beta-lactamase inhibition, and bactericidal effect. Outcomes were clinical cure, clinical success, and adverse events.

RESULTS

When studies were analyzed separately, we found significant differences between cefpodoxim and cefaclor in relation to clinical cure, and between loracarbef and doxycycline in relation to clinical success. When data was pooled, sulphonamides were significantly more effective than penicillins in relation to clinical cure, and macrolids were more effective than penicillins in relation to clinical success, whereas cephalosporins caused significantly less adverse events than penicillins. When studies were stratified (standard classic meta-analysis), antibiotics with beta-lactamase inhibition offered significantly more clinical cures than antibiotics without beta-lactamase inhibition. However, this significant effect was only due to one study from Southern Europe, published before 1991.

CONCLUSION

Differences in outcome between antimicrobial treatments of acute sinusitis in otherwise healthy adults and adolescents appear to be small. Therefore, the cheapest antimicrobial treatment can be selected.

Clarithromycin. A review of its efficacy in the treatment of respiratory tract infections in immunocompetent patients

Clarithromycin is a broad spectrum macrolide antibacterial agent active in vitro and effective in vivo against the major pathogens responsible for respiratory tract infections in immunocompetent patients. It is highly active in vitro against pathogens causing atypical pneumonia (Chlamydia pneumoniae, Mycoplasma pneumoniae and Legionella spp.) and has similar activity to other macrolides against Staphylococcus aureus. Streptococcus pyogenes, Moraxella catarrhalis and Streptococcus pneumoniae. Haemophilus influenzae is susceptible or intermediately susceptible to clarithromycin alone, but activity is enhanced when the parent drug and metabolite are combined in vitro. Absorption of clarithromycin is unaffected by food. More than half of an oral dose is systemically available as the parent drug and the active 14-hydroxy metabolite. Pharmacokinetics are nonlinear, with plasma concentrations increasing in more than proportion to the dosage. First-pass metabolism results in the rapid appearance of the active metabolite 14-hydroxy-clarithromycin in plasma. Clarithromycin and its active metabolite are found in greater concentrations in the tissues and fluids of the respiratory tract than in plasma. Dosage adjustments are required for patients with severe renal failure, but not for elderly patients or those with hepatic impairment. Drug interactions related to the cytochrome P450 system may occur with clarithromycin use. In addition to the standard immediate-release formulation for administration twice daily, a modified-release formulation of clarithromycin is now available for use once daily. In dosages of 500 to 1000 mg/day for 5 to 14 days, clarithromycin was as effective in the treatment of community-acquired upper and lower respiratory tract infections in hospital and community settings as beta-lactam agents (with or without a beta-lactamase inhibitor), cephalosporins and most other macrolides. Clarithromycin was similar in efficacy to azithromycin in comparative studies and is as effective as and better tolerated than erythromycin. Adverse events are primarily gastrointestinal in nature, but result in fewer withdrawals from therapy than are seen with erythromycin. Clarithromycin provides similar clinical and bacteriological efficacy to that seen with beta-lactam agents, cephalosporins and other macrolides. It offers a cost-saving alternative to intravenous erythromycin use in US hospitals and is available in both once-daily and twice-daily formulations. The spectrum of activity of clarithromycin against common and emerging respiratory tract pathogens may make it suitable for use in the community as empirical therapy of respiratory tract infections in both children and adults.

Primary-care-based randomised placebo-controlled trial of antibiotic treatment in acute maxillary sinusitis

BACKGROUND

The value of antibiotics in acute rhinosinusitis is uncertain. Although maxillary sinusitis is commonly diagnosed and treated in general practice, no effectiveness studies have been done on unselected primary-care patients. We used a randomised, placebo-controlled design to test the hypothesis that there would be an improvement associated with amoxycillin treatment for acute maxillary sinusitis patients presenting to general practice.

METHODS

Adult patients with suspected acute maxillary sinusitis were referred by general practitioners for radiographs of the maxillary sinus. Those with radiographic abnormalities (n = 214) were randomly assigned treatment with amoxycillin (750 mg three times daily for 7 days; n = 108) or placebo (n = 106). Clinical course was assessed after 1 week and 2 weeks, and reported relapses and complications were recorded during the following year.

FINDINGS

After 2 weeks, symptoms had improved substantially or disappeared in 83% of patients in the study group and 77% of patients taking placebo. Amoxycillin did not influence the clinical course of maxillary sinusitis nor the frequency of relapses during the 1-year follow-up. Radiographs had no prognostic value, nor were they an effect modifier. Side-effects were recorded in 28% of patients given amoxycillin and in 9% of those taking placebo (p < 0.01). The occurrence of relapses was similar in both groups (21 vs 17%) during the follow-up year.

INTERPRETATION

Antibiotic treatment did not improve the clinical course of acute maxillary sinusitis presenting to general practice. For these patients, an initial radiographic examination is not necessary and initial management can be limited to symptomatic treatment. Whether antibiotics are necessary in more severe cases warrants further study.

Choosing the right macrolide antibiotic. A guide to selection

Macrolide antibiotics have proven to be valuable alternatives to penicillins and cephalosporins for the treatment of a number of infections. Currently, a number of macrolides are available. When choosing a particular macrolide, the types of organisms causing the infection, the tolerability of the drug, convenience of dosing and possible drug interactions all must be taken into account. Erythromycin, azithromycin and clarithromycin are equally effective against most gram-positive organisms. However, clarithromycin and azithromycin have much better activity against Haemophilus influenza and Moraxella catarrhalis. Thus, these 2 drugs are better choices for the treatment of community-acquired pneumonia. However, the low serum concentrations of azithromycin may be a problem in patients with bacteraemia associated with with community-acquired pneumonia. Clarithromycin appears to be effective for the treatment and prophylaxis of Mycobacterium avium complex (MAC) in patients with AIDS, while azithromycin appears to be effective for prophylaxis. Treatment of MAC with azithromycin is currently undergoing study. Although clarithromycin is the macrolide of choice for the treatment of Helicobacter pylori, azithromycin is the preferred macrolide for the treatment of Chlamydia trachomatis infections. The major factor limiting the use of azithromycin and clarithromycin has been their cost. However, these drugs may be cost effective if compliance is improved due to better tolerability and more convenient dosing regimens.

Treatment of acute maxillary sinusitis--comparing cefpodoxime proxetil with amoxicillin

In order to evaluate the clinical efficacy and tolerance of cefpodoxime proxetil, compared with that of amoxicillin in the treatment of acute bacterial maxillary sinusitis, a randomized, double-blind, parallel group comparative study was performed. A total of 286 adults patients were included at 12 centres, each treatment group consisting of 143 patients. Each patient was treated for 10 days and observed before and after treatment. The observations included clinical, roentgenological, bacteriological and laboratory examinations. At inclusion, the most common pathogens were Haemophilus influenzae (24%) and Streptococcus pneumoniae (17%). In the per protocol analysis, 117 patients in the cefpodoxime group and 113 in the amoxicillin group were evaluable for clinical efficacy. The clinical response rates were 96% and 91%, respectively. The corresponding figures in the intent-to-treat analysis were 130 and 128 patients, with clinical response rates of 93% and 88%, respectively. Cefpodoxime proxetil proved clinically as effective as amoxicillin in the treatment of acute bacterial maxillary sinusitis. It was more effective in eradicating H. influenzae and was more efficient in improving the radiological score. Adverse events were reported in 20% of cefpodoxime cases and in 16% of amoxicillin cases. There was no statistically significant difference between the groups.

Efficacy of Clarithromycin vs. Amoxicillin/Clavulanate in the Treatment of Acute Maxillary Sinusitis

A new macrolide drug, clarithromycin (Biaxin®) was compared with amoxicillin/clavulanate (Augmentin®) in a single-blind (investigator-blind), randomized, multicenter study of 497 outpatients with acute maxillary sinusitis; treatment was 500 mg clarithromycin bid (n = 246) or 500 mg amoxicillin/clavulanate tid (n = 251). Pathogens included Streptococcus pneumoniae in 22% of patients, Staphylococcus aureus in 16%, Haemophilus influenzae in 10%, and Moraxella catarrhalis in 7%.

For evaluable patients, clinical success (cure or improvement) was noted for 97% (128/132) of clarithromycin recipients and 93% (119/128) amoxicillin/clavulanate recipients. Clinically significant improvement in signs and symptoms was comparable between groups. Bacteriologic cure rates were 87% (115/132) and 90% (115/128), respectively. Respective pathogen eradication rates were 87% (125/143) and 90% (125/139). Adverse events not due to concurrent conditions occurred in 41% of the former and 46% of the latter group; most were mild to moderate gastrointestinal upsets (21% and 38%, respectively; P ≤ 0.001).

We conclude that clarithromycin appears to be as effective as amoxicillin/clavulanate in acute maxillary sinusitis and may cause fewer gastrointestinal upsets.

Clarithromycin in the treatment of skin and skin structure infections: two multicenter clinical studies. Clarithromycin Study Group

BACKGROUND

Clarithromycin is a new macrolide analog of erythromycin with activity against a number of dermatologic pathogens.

METHODS

The efficacy and safety of clarithromycin, 250 mg bid, were compared with those of reference drugs, cefadroxil and erythromycin, in two multicenter studies: (1) a randomized, double-blind 45-center study, in which clarithromycin or cefadroxil 500 mg bid was given for 5-14 days; and (2) a single-blind 31-center study, in which clarithromycin or erythromycin, 250 mg qid, was given for < or = 14 days.

RESULTS

In the first study, efficacy and safety were evaluated in 299 and 538 patients, respectively. In the second study, the numbers were 141 and 261 patients, respectively. Overall, clarithromycin was as effective and safe as cefadroxil and erythromycin.

CONCLUSIONS

Clarithromycin provides an alternative therapy to cefadroxil and erythromycin for skin and skin structure infections, especially in beta-lactam allergic patients.

Clarithromycin 250 mg b.i.d. for 5 or 10 days in the treatment of adult patients with purulent bronchitis

This Phase III, double-blind, randomized, multicenter study compared the safety and efficacy of clarithromycin, 250 mg b.i.d. administered for either 5 or 10 days, in the treatment of 221 adult patients with purulent bronchitis. Clinical evaluations were performed pre-treatment, during treatment, post-treatment, and at a follow-up visit. Both regimens were well tolerated and effective. No significant differences were observed between patients treated for 5 days and those treated for 10 days in post-treatment, clinical success (98%, 83/85; 99%, 73/74, respectively), or bacterial eradication (100%, 37/37; 94%, 33/35) rates, or in the number of patients reporting drug-related adverse events (16%, 18/112; 24%, 26/109, respectively). Clarithromycin administered for 5 days was at least as safe and as effective as a 10-day regimen in the treatment of purulent bronchitis.

Clarithromycin: review of a new macrolide antibiotic with improved microbiologic spectrum and favorable pharmacokinetic and adverse effect profiles

OBJECTIVE

To compare the new macrolide antibiotic clarithromycin with erythromycin in terms of in vitro activity, pharmacokinetics, pharmacodynamics, clinical efficacy, and toxicity.

DATA IDENTIFICATION

An English-language literature search employing MEDLINE (1987-91), Index Medicus (1987-91), Program and Abstracts of the 30th Interscience Conference on Antimicrobial Agents and Chemotherapy (1990), Program and Abstracts of the 31st Interscience Conference on Antimicrobial Agents and Chemotherapy (1991), and bibliographic reviews of related textbooks and review articles.

STUDY SELECTION

Eighty-five articles were selected. Clinical trials with clarithromycin have been limited, and emphasis was placed on trials reported in the Program and Abstracts of the 30th Interscience Conference on Antimicrobial Agents and Chemotherapy and Program and Abstracts of the 31st Interscience Conference on Antimicrobial Agents and Chemotherapy.

DATA EXTRACTION

Articles were assessed for study quality and specific information addressing the stated purpose. In articles reporting the results of clinical trials, emphasis was placed on comparative efficacy and toxicity.

RESULTS OF DATA ANALYSIS

A review of 24 human trials suggests that clarithromycin is equally effective as erythromycin, penicillin VK, ampicillin, or amoxicillin for treatment of a variety of upper and lower respiratory tract or skin infections. Clarithromycin also appears to be better tolerated than these agents, with a lower incidence of gastrointestinal adverse effects. Limited clinical studies in patients with Mycobacterium leprae or Mycobacterium avium-intracellulare complex (MAI) suggest that clarithromycin may prove to be efficacious and well tolerated in the treatment of these infections.

CONCLUSIONS

Clarithromycin is as effective in vivo as erythromycin, with less gastrointestinal irritation. Additionally, clarithromycin appears to expand the traditional spectrum of macrolide antibiotics, with promising activity against M. leprae and MAI.

Clarithromycin. A review of its antimicrobial activity, pharmacokinetic properties and therapeutic potential

Clarithromycin is an acid-stable orally administered macrolide antimicrobial drug, structurally related to erythromycin. It has a broad spectrum of antimicrobial activity, similar to that of erythromycin and inhibits a range of Gram-positive and Gram-negative organisms, atypical pathogens and some anaerobes. Significantly, clarithromycin demonstrates greater in vitro activity than erythromycin against certain pathogens including Bacteroides melaninogenicus, Chlamydia pneumoniae, Chlamydia trachomatis, Mycobacterium chelonae subspecies--chelonae and--abscessus, Mycobacterium leprae, Mycobacterium marinum, Mycobacterium avium complex, Legionella spp. and, when combined with its 14-hydroxy metabolite, against Haemophilus influenzae. However, bacterial strains resistant to erythromycin are also generally resistant to clarithromycin. The antimicrobial activity of clarithromycin appears to be enhanced by the formation in vivo of the microbiologically active 14-hydroxy metabolite. In combination, additive or synergistic activity against a variety of pathogens including Haemophilus influenzae, Moraxella catarrhalis, Legionella species (principally Legionella pneumophila) and various staphylococci and streptococci has been demonstrated. Clarithromycin has a superior pharmacokinetic profile to that of erythromycin, allowing the benefits of twice daily administration with the potential for increased compliance among outpatients where a more frequent regimen for erythromycin might otherwise be indicated. The clinical efficacy of clarithromycin has been confirmed in the treatment of infections of the lower and upper respiratory tracts (including those associated with atypical pathogens), skin/soft tissues, and in paediatrics. Clarithromycin was as effective as erythromycin and other appropriate drugs including beta-lactams (penicillins and cephalosporins) in some of the above infections. A most promising indication for clarithromycin appears to be in the treatment of immunocompromised patients infected with M. avium complex, M. chelonae sp. and Toxoplasma sp. Small initial trials in this setting reveal clarithromycin alone or in combination with other antimicrobials to be effective in the eradication or amelioration of these infections. Noncomparative studies have provided preliminary evidence for the effectiveness of clarithromycin in the treatment of infections of the urogenital tract, oromaxillofacial and ophthalmic areas. However, the promising in vitro and preliminary in vivo activity of clarithromycin against Mycobacterium leprae and Helicobacter pylori warrant further clinical trials to assess its efficacy in patients with these infections. Despite the improved pharmacokinetic profile and in vitro antimicrobial activity of clarithromycin over erythromycin, comparative studies of patients with community-acquired infections reveal the 2 drugs to be of equivalent efficacy. However, clarithromycin demonstrates greater tolerability, principally by inducing fewer gastrointestinal disturbances.(ABSTRACT TRUNCATED AT 400 WORDS)

The new macrolide antibiotics. Azithromycin and clarithromycin

Azithromycin (Zithromax) and clarithromycin (Biaxin Filmtabs) are new macrolide antibiotics with several advantages over erythromycin. Azithromycin has an expanded spectrum against gram-negative bacilli. Clarithromycin is more active than erythromycin against gram-positive cocci; combination with its 14-hydroxy metabolite enhances its antimicrobial activity. These new agents penetrate well into tissues and concentrate in macrophages and polymorphonuclear leukocytes. They offer improved bioavailability and an extended half-life. The high tissue-to-serum level and extended elimination half-life of azithromycin allow for once-daily dosing and short-course therapy. Clarithromycin and 14-hydroxyclarithromycin maintain high serum levels and tissue-to-serum concentrations. Both of these new agents have been effective in streptococcal pharyngitis, acute sinusitis, acute lower respiratory tract infections, skin and soft-tissue infections, and sexually transmitted diseases. A single dose of azithromycin is effective for genital chlamydial infections. Adverse reactions to these agents have usually been mild and have not included serious organ toxicity. In clinical trials, the rate of premature discontinuation of therapy has been less than observed with erythromycin. Azithromycin and clarithromycin should be used according to the current guidelines of the Food and Drug Administration; their future role will be determined by ongoing laboratory and clinical evaluations.

Comparative safety and efficacy of clarithromycin and ampicillin in the treatment of out-patients with acute bacterial exacerbation of chronic bronchitis

In an open, randomized trial, adult non-hospitalized patients with acute bacterial exacerbation of chronic bronchitis were treated with 500 mg clarithromycin twice daily (n = 53) or 500 mg ampicillin four times daily (n = 50). Causative pathogens included S. pneumoniae, M. catarrhalis, H. influenzae, H. parainfluenzae and S. aureus. For clinically evaluable patients, successful outcome (cure or improvement) was noted for 53/53 (100%) clarithromycin-treated patients and 46/47 (98%) ampicillin-treated patients. Clinically significant improvement in signs and symptoms was comparable between treatment groups. There was 100% bacteriological eradication in both treatment groups. Eight patients (15%) in the clarithromycin group and 10 patients (20%) in the ampicillin group reported adverse events, the majority of which were mild or moderate in severity; six events in each treatment group were digestive-system disorders. The new macrolide, clarithromycin, appears to be effective and well-tolerated in the treatment of acute exacerbation of chronic bronchitis.

Clarithromycin, a unique macrolide. A pharmacokinetic, microbiological, and clinical overview

The in vitro and in vivo spectrum of antibacterial activity of clarithromycin is summarized and related to its human pharmacokinetics. In vitro studies by several investigators have documented clarithromycin's activity against bacterial agents of respiratory tract infections, skin and soft tissue infections, and sexually transmitted diseases. Clinical cure rates of 52%-83% (pneumonia), 79%-96% (bronchitis), 82%-96% (pharyngitis), 58% (sinusitis), and 78% (skin/skin-structure infections) have been reported in patients receiving clarithromycin in comparative trials. Respective bacteriologic eradication rates in clarithromycin recipients have been reported as 57%-89%, 79%-96%, 88%-100%, 89%, and 90%. In vitro and in vivo studies suggest that clarithromycin, when combined with its major human metabolite, 14-hydroxyclarithromycin, is also effective against Haemophilus influenzae. A New Drug Application claiming efficacy in the treatment of lower respiratory tract infection, sinusitis, pharyngitis, and skin and skin-structure infections caused by susceptible pathogens has been filed with the Food and Drug Administration (FDA). This review summarizes relevant pharmacokinetic, microbiological, and clinical data for clarithromycin.

Bactericidal activity of clarithromycin and its 14-hydroxy metabolite against Haemophilus influenzae and streptococcal pathogens

The serum bactericidal activity of clarithromycin in six normal human volunteers was determined after oral doses of 500 mg. The mean plasma levels of clarithromycin plus 14-hydroxy clarithromycin were 2.11 micrograms/mL after the second dose and 4.36 micrograms/mL after the sixth dose. The mean serum bactericidal titer against Haemophilus influenzae after the second dose was 1:8 and after the sixth dose 1:16 when unheated serum was used. Similar values were obtained when serum to which clarithromycin and 14-hydroxy clarithromycin was added was tested. Mean serum bactericidal titers against H. influenzae determined in Haemophilus test broth or heated serum were 1:2 and 1:4, respectively. Against Streptococcus pneumoniae and Streptococcus pyogenes, there was greater than 1:16 serum bactericidal levels at 12 hours after the sixth dose of clarithromycin.