Azithromycin (Zithromax®) versus Clarithromycin (Biaxin®)
Based on "Antibiotic and Chemotherapy"
written by Roger G. Finch
Main differences between Azithromycin and Clarithromycin
Azithromycin | Clarithromycin | |
---|---|---|
Drug class | Macrolide antibiotic | |
Dosing schedule | more convenient once a day dosing | twice-a-day dosing |
Spectrum of activity | More rapid killing and longer postantibiotic effect against H. influenzae | Significantly longer postantibiotic effect against S. pneumonia |
Better in vitro activity against M catarrhalis and M pneumoniae | More active in vitro against the atypical respiratory pathogens (e.g., against Legionella pneumophila and Chlamydia pneumoniae) | |
Has activity against enteric pathogens, including Escherichia coli, Salmonella spp, Yersinia enterocolitica, and Shigella spp4 | Has no in vitro activity against these enteric pathogens | |
More active against Campylobacter jejuni | More active against Helicobacter pylori | |
Adverse effects & Toxicity | Small risk of QT interval prolongation | Greater risk of QT interval prolongation 5 |
Drug interactions | Does not affect CYP isoenzymes | Clarithromycin is an inhibitor of cytochrome CYP3A4 isoenzymes and may cause drug interactions with medications that require CYP3A4 enzyme for their metabolism. |
Other notes | Azithromycin distributes less well across bronchial membranes than clarithromycin |
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Pneumonia
Azithromycin (3-day, once-daily course) is as effective and well tolerated as clarithromycin (10-day, twice-daily course) in the treatment of mild to moderate community-acquired pneumonia2.
Results of randomized, multicentre study comparing azithromycin versus clarithromycin in adults with mild to moderate community-acquired pneumonia 2 | Azithromycin | Clarithromycin |
---|---|---|
Regimen | 500 mg once daily for 3 days | 250 mg twice daily for 10 days |
Satisfactory clinical response, number of patients (%) | 83 of 88 (94%) | 84 of 88 (95%) |
Number (%) of eradicated pathogens which were isolated from patients before treatment | 31 of 32 (97%) | 32 of 35 (91%) |
Incidences of adverse events | similar |
|
Relapsed patients | 1 | 1 |
Number of patients who discontinued therapy due to severe adverse events | 0 | 2 (2%) |
Acute exacerbation of chronic bronchitis
Azithromycin is equivalent to clarithromycin for the treatment of acute exacerbation of chronic bronchitis (AECB) in adults1.
Results of randomized, double-blind, double-dummy, multicenter study comparing azithromycin versus clarithromycin for acute exacerbation of chronic bronchitis 1 | Azithromycin | Clarithromycin |
---|---|---|
Regimen | 500 mg once daily for 3 days | 250 mg twice daily for 10 days |
The clinical cure (based on direct observation of the patient) rates | 85% | 82% |
Clinical success rates on day 10-12 | 93% | 94% |
Bacteriologic success rates at test of cure: S. pneumoniae H. influenzae M. catarrhalis |
90.6% 71.4% 100% |
85.2% 81.3% 86.7% |
Incidence of adverse events abdominal cramps diarrhea nausea |
20.9% 6.3% 4.4% 4.4% |
26.8% 6.1% 5.5% 3.7% |
Otitis media
Both azithromycin and clarithromycin are effective for the treatment of children with acute otitis media (infection of the middle ear)3.
Results of randomized, open clinical trial comparing azithromycin and clarithromycin in children aged 6 months to 12 years of age with acute otitis media with effusion 3 | Azithromycin | Clarithromycin |
---|---|---|
Regimen | 10 mg/kg once daily for 3 days | 15 mg/kg day divided into 2 equal doses for 10 days |
Satisfactory clinical response, number of patients (%) | 50 (100%) | 45 (95.7%) |
Rates of persistence of middle ear effusion and possible side effects | comparable |
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Further reading
- Azithromycin (Zithromax) facts
- Azithromycin vs Doxycycline
- Azithromycin vs Amoxicillin
- Azithromycin vs Amoxicillin/Clavulanate
- Azithromycin vs Penicillin
- Azithromycin vs Cefdinir
References
- 1. Swanson RN, Lainez-Ventosilla A, De Salvo MC, Dunne MW, Amsden GW. Azithromycin compared with clarithromycin for acute exacerbation of chronic bronchitis. Treat Respir Med. 2005;4(1):31-9. PubMed
- 2. O'Doherty B, Muller O. Randomized, multicentre study of the efficacy and tolerance of azithromycin versus clarithromycin in the treatment of adults with mild to moderate community-acquired pneumonia. Eur J Clin Microbiol Infect Dis. 1998 Dec;17(12):828-33. PubMed
- 3. Arguedas A, Loaiza C, Rodriguez F, Herrera ML, Mohs E. Comparative trial of 3 days of azithromycin versus 10 days of clarithromycin in the treatment of children with acute otitis media with effusion. J Chemother. 1997 Feb;9(1):44-50. PubMed
- 4. Retsema J, Girard A, Schelkly W, et al. Spectrum and mode of action of azithromycin (CP-62,993), a new 15-membered-ring macrolide with improved potency against gram- negative organisms. Antimicrob Agents Chemother 1987;31:1939–47.
- 5. Guo D, Cai Y, Chai D, Liang B, Bai N, Wang R. The cardiotoxicity of macrolides: a systematic review. Pharmazie. 2010 Sep;65(9):631-40. PubMed
Published: January 10, 2014
Last updated: May 15, 2017
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