What is the recommended dosage and treatment guidelines for oral cefdinir (Cefdinir) for bacterial infections?

Oral Cefdinir Dosing and Treatment Guidelines

Cefdinir is dosed at 300 mg twice daily or 600 mg once daily in adults for 5-10 days depending on the infection, and 14 mg/kg/day (maximum 600 mg/day) in one or two divided doses in pediatric patients aged 6 months and older. 1

Adult and Adolescent Dosing

Standard dosing for adults is 300 mg twice daily or 600 mg once daily, with treatment duration of 5-10 days based on infection type. 1, 2

• Community-acquired pneumonia: 300 mg twice daily for 10 days 1
• Acute bacterial exacerbation of chronic bronchitis: 300 mg twice daily for 5-10 days 1
• Acute maxillary sinusitis: 300 mg twice daily or 600 mg once daily for 10 days 1
• Pharyngitis/tonsillitis: 300 mg twice daily or 600 mg once daily for 5-10 days 1
• Uncomplicated skin and skin structure infections: 300 mg twice daily for 10 days 1

Pediatric Dosing (Age 6 Months Through 12 Years)

The total daily dose is 14 mg/kg, up to a maximum of 600 mg per day, administered as either 7 mg/kg every 12 hours or 14 mg/kg once daily. 1

Weight-Based Dosing Chart (Using 250 mg/5 mL Suspension):

• 18 kg (40 lbs): 2.5 mL every 12 hours or 5 mL once daily 1
• 27 kg (60 lbs): 3.75 mL every 12 hours or 7.5 mL once daily 1
• 36 kg (80 lbs): 5 mL every 12 hours or 10 mL once daily 1
• ≥43 kg (95 lbs): 6 mL every 12 hours or 12 mL once daily (maximum 600 mg/day) 1

Infection-Specific Pediatric Dosing:

• Acute otitis media: 7 mg/kg every 12 hours for 5-10 days OR 14 mg/kg once daily for 10 days 1
• Acute maxillary sinusitis: 7 mg/kg every 12 hours for 10 days OR 14 mg/kg once daily for 10 days 1
• Pharyngitis/tonsillitis: 7 mg/kg every 12 hours for 5-10 days OR 14 mg/kg once daily for 10 days 1
• Uncomplicated skin infections: 7 mg/kg every 12 hours for 10 days (once-daily dosing has NOT been studied for skin infections) 1

Renal Dosing Adjustments

For creatinine clearance <30 mL/min, reduce dose to 300 mg once daily in adults or 7 mg/kg once daily (up to 300 mg) in pediatric patients. 1

• Hemodialysis patients: Give 300 mg (or 7 mg/kg) every other day, with an additional dose after each dialysis session 1

Antimicrobial Spectrum and Clinical Context

Cefdinir provides intermediate-tier coverage among oral cephalosporins for respiratory pathogens:

• Against S. pneumoniae: Cefdinir achieves 63-75% coverage based on pharmacokinetic/pharmacodynamic breakpoints, placing it in the middle tier alongside cefuroxime axetil and cefpodoxime, but inferior to high-dose amoxicillin-clavulanate (95-97%) and respiratory fluoroquinolones (99%) 3
• Against H. influenzae: Cefdinir provides 70-85% coverage, superior to cefprozil but inferior to cefpodoxime and amoxicillin-clavulanate (95-100%) 3
• Against M. catarrhalis: Cefdinir achieves 78-96% coverage 3

Cefdinir is stable against 13 common beta-lactamases, making it effective against beta-lactamase-producing strains of H. influenzae and M. catarrhalis. 4, 5

Critical Administration Considerations

Cefdinir may be administered without regard to meals in all age groups. 1

The oral suspension has superior taste and palatability compared to other oral antimicrobials, which improves adherence, particularly in pediatric patients. 3, 2, 6

After reconstitution, the suspension remains stable for 10 days at room temperature (25°C/77°F); shake well before each use and discard any unused portion after 10 days. 1

Common Pitfalls and When to Consider Alternatives

Treatment Failure Scenarios:

If clinical response is inadequate after 72 hours of cefdinir therapy, switch to high-dose amoxicillin-clavulanate (90 mg/6.4 mg per kg per day in children or 4 g/250 mg per day in adults) or consider parenteral ceftriaxone. 7

The limitations of cefdinir that may lead to treatment failure include:

• Moderate activity against drug-resistant S. pneumoniae (DRSP): Cefdinir has no clinically significant activity against DRSP 3
• Inferior coverage compared to high-dose amoxicillin: For serious infections or treatment failures, escalation is necessary 7

Alternative Agents for Specific Scenarios:

For beta-lactamase-negative H. influenzae, amoxicillin (75-100 mg/kg/day) is preferred; for beta-lactamase-producing strains, cefdinir, cefixime, cefpodoxime, or ceftibuten are appropriate alternatives. 3

For penicillin-allergic adults with respiratory infections, respiratory fluoroquinolones (levofloxacin, moxifloxacin) provide 90-92% predicted clinical efficacy. 7

For suspected MRSA skin infections, clindamycin (30-40 mg/kg/day in three divided doses) provides superior gram-positive coverage, though cefdinir demonstrated 92% cure rates for MRSA in one comparative trial. 7, 8

Adverse Effects and Tolerability

Diarrhea is the most common adverse event, occurring in approximately 10% of cefdinir recipients compared to 4% with cephalexin. 8

Other common adverse events include:

• Nausea: 3-6% of patients 8
• Vaginal mycosis: 3-6% of female patients 8

Discontinuation rates due to adverse events are generally similar between cefdinir and comparator agents despite higher diarrhea rates. 6

Clinical Positioning

Cefdinir represents a second-line alternative to first-line agents (amoxicillin, high-dose amoxicillin-clavulanate) for community-acquired respiratory tract infections and uncomplicated skin infections, particularly valuable in areas with elevated beta-lactamase production rates. 2, 6, 5

The convenience of once- or twice-daily dosing, superior palatability in pediatric formulations, and broad beta-lactamase stability make cefdinir a practical choice when first-line therapy is contraindicated or has failed, though clinicians must recognize its intermediate-tier activity against S. pneumoniae limits its utility in severe or drug-resistant infections. 3, 2, 6