What is the recommended dosing frequency of cefdinir (Omnicef) for the treatment of sinusitis?

Cefdinir Dosing for Sinusitis: Once or Twice Daily

For acute bacterial sinusitis, cefdinir can be dosed either 300 mg twice daily OR 600 mg once daily for 10 days in adults and adolescents, with equivalent clinical efficacy between the two regimens. 1, 2

FDA-Approved Dosing Regimens

Both dosing schedules are FDA-approved and clinically validated:

• Once-daily dosing: 600 mg once daily for 10 days 2
• Twice-daily dosing: 300 mg every 12 hours for 10 days 2

The FDA label explicitly states that once-daily dosing for 10 days is as effective as twice-daily dosing for acute maxillary sinusitis 2. This provides flexibility based on patient preference and adherence considerations.

Clinical Evidence Supporting Both Regimens

Multiple randomized controlled trials demonstrate equivalent efficacy between once-daily and twice-daily cefdinir dosing:

• Both regimens showed similar clinical and bacteriological cure rates in acute bacterial rhinosinusitis 3, 4
• In a large multicenter trial of 569 patients, cefdinir 600 mg once daily was therapeutically as effective as or better than amoxicillin-clavulanate 500/125 mg three times daily 4
• The once-daily regimen had significantly fewer treatment discontinuations due to adverse events compared to twice-daily dosing 4

Practical Considerations for Dosing Selection

Choose once-daily dosing (600 mg) when:

• Patient adherence is a concern—simpler regimens improve compliance 3
• Convenience is prioritized—cefdinir is the only once-daily beta-lactam recommended for first-line acute bacterial rhinosinusitis 3
• The patient has difficulty with multiple daily doses 5

Choose twice-daily dosing (300 mg BID) when:

• The patient has mild renal impairment (creatinine clearance 30-60 mL/min)—allows dose adjustment flexibility 2
• The patient prefers splitting doses to minimize gastrointestinal side effects 6

Pediatric Dosing (Ages 6 Months Through 12 Years)

For pediatric patients, cefdinir is dosed at 14 mg/kg/day, which can be given as:

• Once-daily: 14 mg/kg once daily for 10 days 2
• Twice-daily: 7 mg/kg every 12 hours for 10 days 2

The maximum daily dose is 600 mg regardless of weight 2. Once-daily dosing has been validated in pediatric sinusitis and offers superior convenience 2, 6.

Treatment Duration and Monitoring

Standard treatment duration is 10 days for acute maxillary sinusitis 1, 2. Reassess patients at 3-5 days: if no clinical improvement occurs, consider switching to an alternative antibiotic such as high-dose amoxicillin-clavulanate or a respiratory fluoroquinolone 7, 1.

Position in Treatment Algorithm

Cefdinir is recommended as:

• An alternative first-line option for patients with penicillin allergy or intolerance 7
• A second-line option for patients who fail initial amoxicillin therapy 7, 1
• A preferred choice in areas with elevated beta-lactamase production by Haemophilus influenzae 5, 6

Cefdinir provides good coverage against Streptococcus pneumoniae (comparable to second-generation cephalosporins) and H. influenzae (similar to cefuroxime axetil), though its activity against H. influenzae is lower than cefpodoxime proxetil 8.

Critical Advantages of Once-Daily Dosing

The once-daily regimen offers specific clinical benefits:

• Superior patient adherence and satisfaction 3
• Fewer treatment discontinuations due to adverse events 4
• Excellent taste and palatability of the oral suspension in pediatric patients 8, 6
• Convenient dosing that can be administered without regard to meals 2

Special Populations

For patients with renal insufficiency (creatinine clearance <30 mL/min):

• Reduce dose to 300 mg once daily in adults 2
• Reduce dose to 7 mg/kg once daily (up to 300 mg) in pediatric patients 2

For patients on hemodialysis:

• Give 300 mg (or 7 mg/kg) every other day, with an additional dose at the conclusion of each hemodialysis session 2