Azithromycin (Zithromax) vs Cefdinir (Omnicef)
Based on "Antibiotic and Chemotherapy"
written by Roger G. Finch
Azithromycin advantages over Cefdinir
- Unlike cefdinir, azithromycin has excellent activity against atypical bacteria.
- Generic azithromycin is less expensive than cefdinir.
Cefdinir advantages over Azithromycin
- Cefdinir is very effective against penicillin-sensitive Pneumococcus and methicillin-sensitive Staphylococcus aureus.
- Cefdinir suspension has good taste and smell.
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| Azithromycin | Cefdinir |
| Brand names | |
| • Zithromax® • Z-PAK® • Sumamed® |
• Omnicef® |
| Drug class | |
| • Antibiotic | |
| • Macrolide | • Cephalosporin, 3rd-generation |
| Dose formulations | |
| • Tablets • Capsules • Powder for solution • Oral suspension |
• Capsules • Oral suspension |
| FDA-approved indications | |
| • Acute otitis media • Pharyngitis/tonsillitis • Sinusitis • Acute exacerbations of chronic bronchitis • Community-acquired pneumonia • Skin and skin structure infections (uncomplicated) |
|
| • Urethritis and cervicitis • Genital ulcer disease |
|
| "Off-label" uses | |
| • Acne • Gonococcal infections • Lyme disease |
• Acute uncomplicated cystitis |
| Mechanism of action | |
| • Azithromycin inhibits bacterial protein synthesis. • Its action is mainly bacteriostatic. |
• Cefdinir inhibits bacterial cell wall synthesis. • Its action is mainly bactericidal. |
| Half-life | |
| • 40 hours | • 1.5 hours |
| Oral bioavailability | |
| • 37% | • 16-25% • Iron containing products reduce cefdinir absorption by up to 80% |
| Metabolism, Elimination | |
| • Excreted billiary, mainly as unchanged drug in the feces. Urinary excretion is about 6%. |
• Cefdinir doesn't undergo significant metabolism. • Cefdinir is eliminated predominantly via the kidneys. |
| Contraindications | |
| • Allergy to macrolide or ketolide antibiotics. • History of hepatic dysfunction associated with prior use of azithromycin. |
• Allergy to the cephalosporin antibiotics. |
| Side effects | |
| • Diarrhea • Nausea • Abdominal pain • Vomiting |
• Diarrhea • Abdominal pain, diarrhea, • Nausea • Cefdinir binds to iron in the gut, and may turn the stool read |
| Pregnancy category | |
| B | |
Azithromycin vs Cefdinir for Otitis media
Both antibiotics are FDA-approved for the treatment of bacterial ear infection. Cefdinir is considered as a second line agent. The current pediatric guidelines do not recommend to use azithromycin to treat otitis media.
Cefdinir and azithromycin have comparable effectiveness in the treatment of acute otitis media1.
| Results of multicenter, prospective, investigator-blinded study of children (between the ages of 6 months and 6 years) with a clinical diagnosis of AOM 1 | Azithromycin | Cefdinir |
|---|---|---|
| Regimen | 10 mg/kg once daily on day 1 and 5 mg/kg once daily on days 2 through 5 | 7 mg/kg q12h for 5 days |
| Clinical cure rates | 85% (149 patients of 176) | 87% (151 patients of 174) |
| Clinical cure rates at the follow-up visit | 86% | 76% |
| Parents' satisfaction with regard to ease of use, taste, compliance, health care resource utilization, and missed days of work and day-care | similar |
|
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Further reading
- Azithromycin (Zithromax) facts
- Azithromycin vs Amoxicillin
- Azithromycin vs Amoxicillin/Clavulanate
- Azithromycin vs Ciprofloxacin
- Azithromycin vs Clarithromycin
- Azithromycin vs Doxycycline
- Azithromycin vs Penicillin
References
- 1. Block SL, Cifaldi M, Gu Y, Paris MM. A comparison of 5 days of therapy with cefdinir or azithromycin in children with acute otitis media. Clin Ther. 2005 Jun;27(6):786-94. PubMed
Published: February 21, 2018
Last updated: February 21, 2018
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