What is the recommended dose of cefdinir (Omnicef) for treating bacterial sinusitis?

Cefdinir Dosing for Acute Bacterial Sinusitis

For adults with acute bacterial sinusitis, cefdinir should be dosed at 300 mg twice daily or 600 mg once daily for 10 days, and is recommended as a first-line option for patients with mild disease who have not received antibiotics in the previous 4-6 weeks. 1, 2, 3

Adult Dosing Regimen

• The FDA-approved dose is 300 mg orally twice daily OR 600 mg orally once daily for 10 days 3
• Both dosing regimens demonstrate equivalent clinical efficacy of approximately 90% cure rates in acute bacterial sinusitis 4
• Cefdinir may be administered without regard to meals 3

Pediatric Dosing (Age 6 Months Through 12 Years)

• For acute maxillary sinusitis: 7 mg/kg every 12 hours OR 14 mg/kg once daily for 10 days 3
• The maximum daily dose is 600 mg per day regardless of weight 3
• Once-daily dosing for 10 days is as effective as twice-daily dosing for sinusitis 3

Position in Treatment Algorithm

• Cefdinir ranks in the 83-88% predicted clinical efficacy tier for acute bacterial sinusitis, comparable to high-dose amoxicillin, cefpodoxime proxetil, cefuroxime axetil, and TMP/SMX 1
• This is slightly below respiratory fluoroquinolones and high-dose amoxicillin-clavulanate (90-92% efficacy) but significantly better than macrolides (77-81%) 1
• Cefdinir is specifically recommended as a first-line option for adults with mild disease who have not received antibiotics in the previous 4-6 weeks 1, 2

Appropriate Patient Selection

• Cefdinir is an excellent choice for patients with documented penicillin allergy, as second- and third-generation cephalosporins have negligible cross-reactivity risk 5, 2
• It provides superior coverage against β-lactamase-producing Haemophilus influenzae and Moraxella catarrhalis compared to amoxicillin alone 6, 7
• Do NOT use cefdinir for patients with moderate-to-severe disease or recent antibiotic exposure (within 4-6 weeks)—these patients require more aggressive initial therapy such as high-dose amoxicillin-clavulanate or respiratory fluoroquinolones 1, 2

Renal Dosing Adjustments

• For adults with creatinine clearance <30 mL/min: 300 mg once daily 3
• For pediatric patients with creatinine clearance <30 mL/min/1.73 m²: 7 mg/kg (up to 300 mg) once daily 3
• For patients on hemodialysis: 300 mg (or 7 mg/kg) every other day, with an additional dose at the conclusion of each hemodialysis session 3

Treatment Failure Protocol

• Reassess at 72 hours (3 days): if no improvement or worsening symptoms, switch antibiotics or re-evaluate the diagnosis 5, 2, 8
• Consider switching to high-dose amoxicillin-clavulanate (4 g/250 mg per day for adults; 90 mg/kg/day amoxicillin component for children) 1, 2
• Alternatively, switch to a respiratory fluoroquinolone (levofloxacin 500-750 mg once daily or moxifloxacin 400 mg once daily) for treatment failures 1, 2

Microbiologic Coverage

• Cefdinir demonstrates excellent activity against Streptococcus pneumoniae (including penicillin-susceptible strains), Haemophilus influenzae, and Moraxella catarrhalis 4, 6, 7
• It is stable to hydrolysis by 13 common β-lactamases, providing good coverage against β-lactamase-producing strains 7, 9
• However, cefdinir has limited activity against drug-resistant S. pneumoniae (DRSP), similar to other second- and third-generation cephalosporins 1

Critical Pitfalls to Avoid

• Complete the full 10-day course even if symptoms improve earlier to prevent relapse and resistance development 5, 2
• Do not use first-generation cephalosporins (cephalexin, cefadroxil) or cefaclor for sinusitis—they have inadequate coverage against H. influenzae and predicted clinical efficacy of only 65-68% 1, 2
• Avoid using cefdinir for patients who have received antibiotics in the previous 4-6 weeks, as recent antimicrobial exposure increases the risk of resistant organisms 1
• Reassess at 72 hours if no improvement to avoid delayed treatment of resistant organisms 5, 2, 8

Adverse Effects and Tolerability

• The most common adverse event is mild diarrhea, occurring in approximately 20% of patients 4
• Cefdinir causes fewer adverse events requiring treatment discontinuation compared to amoxicillin-clavulanate 4
• The oral suspension formulation is very well accepted among children due to superior taste and palatability 1, 7, 10