Cefdinir Dosing for Adult Ear Infections
For adults with acute otitis media (ear infection), cefdinir is dosed at 300 mg orally twice daily for 10 days, though this agent is not a first-line choice for this indication. 1
FDA-Approved Adult Dosing
The FDA label for cefdinir does not specifically list acute otitis media as an approved indication in adults, as this condition is primarily pediatric. 1 However, when used off-label for adult ear infections, the standard dosing follows the general respiratory tract infection regimen:
- Standard dose: 300 mg orally every 12 hours (twice daily) 1
- Duration: 10 days for respiratory tract infections 1
- Administration: May be taken without regard to meals 1
Clinical Context and Limitations
Why Cefdinir Is Not Preferred for Adult Ear Infections
While cefdinir has activity against common respiratory pathogens including Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis, it is not recommended as first-line therapy for adult ear infections. 2 The 2004 antimicrobial treatment guidelines for acute bacterial rhinosinusitis rank cefdinir with a predicted clinical efficacy of only 83-88% in adults, which is lower than high-dose amoxicillin/clavulanate (90-92%) or respiratory fluoroquinolones (90-92%). 2
Spectrum of Activity
- Good coverage: Penicillin-susceptible S. pneumoniae, comparable to second-generation cephalosporins 2
- Moderate coverage: H. influenzae activity similar to cefuroxime axetil but lower than cefpodoxime proxetil 2
- Beta-lactamase stability: Stable against commonly occurring plasmid-mediated beta-lactamases from H. influenzae and M. catarrhalis 3, 4
- No activity: Drug-resistant S. pneumoniae (DRSP) 2
Dosing Adjustments
Renal Impairment
- Creatinine clearance <30 mL/min: Reduce dose to 300 mg once daily 1
- Hemodialysis patients: 300 mg every other day, with an additional 300 mg dose after each dialysis session 1
Common Pitfalls to Avoid
Recent antibiotic exposure: If the patient received antibiotics in the previous 4-6 weeks, cefdinir is not appropriate—use high-dose amoxicillin/clavulanate or a respiratory fluoroquinolone instead 2
Moderate to severe infection: Cefdinir is only suitable for mild infections; moderate disease requires more potent agents 2
Drug-resistant pneumococcus: Cefdinir has no clinically significant activity against DRSP, making it unsuitable in areas with high resistance rates 2
Iron and antacid interactions: Cefdinir absorption is inhibited by multivalent cations (iron, aluminum, magnesium); separate administration by at least 2 hours 3, 4
Alternative First-Line Options
For adult ear infections, consider these preferred alternatives:
- High-dose amoxicillin/clavulanate: 2000 mg/125 mg twice daily (predicted efficacy 90-92%) 2
- Respiratory fluoroquinolones: Levofloxacin, moxifloxacin, or gatifloxacin (predicted efficacy 90-92%) 2
- Cefpodoxime proxetil: Superior H. influenzae coverage compared to cefdinir 2
Adverse Effects
The most common adverse event with cefdinir is diarrhea, occurring in approximately 10-20% of patients, though this is generally mild and rarely requires discontinuation. 3, 5, 6 Other adverse effects include nausea (3-6%) and vaginal mycosis in females (3-6%). 6