What is the recommended cefdinir dosing for adults (including severe infections) and children, and how should the dose be adjusted in renal impairment?

Cefdinir Dosing

Cefdinir should be dosed at 300 mg twice daily or 600 mg once daily in adults for respiratory and skin infections, with dose reduction to 300 mg once daily in patients with creatinine clearance <30 mL/min. 1

Adult Dosing

Standard Regimen

• 300 mg orally twice daily for 5-10 days, depending on the infection type 1, 2
• 600 mg orally once daily is equally effective for respiratory tract infections when given for 10 days 1, 2
• May be administered without regard to meals 1

Severe Infections

• For community-acquired pneumonia and acute bacterial exacerbations of chronic bronchitis, 300 mg twice daily is the preferred regimen to ensure adequate coverage 2, 3
• The twice-daily regimen provides more consistent serum concentrations for severe infections 3

Pediatric Dosing (Age 6 Months Through 12 Years)

Standard Dosing

• Total daily dose: 14 mg/kg/day (maximum 600 mg/day) 1
• Can be administered as:
  • 7 mg/kg every 12 hours, OR
  • 14 mg/kg once daily 1

Duration by Infection Type

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

Weight-Based Dosing Chart (125 mg/5 mL suspension)

• 9 kg (20 lbs): 2.5 mL every 12 hours or 5 mL once daily 1
• 18 kg (40 lbs): 5 mL every 12 hours or 10 mL once daily 1
• 27 kg (60 lbs): 7.5 mL every 12 hours or 15 mL once daily 1
• 36 kg (80 lbs): 10 mL every 12 hours or 20 mL once daily 1
• ≥43 kg (95 lbs): 12 mL every 12 hours or 24 mL once daily (maximum dose) 1

Renal Impairment Dosing

Adults

• Creatinine clearance <30 mL/min: 300 mg once daily 1
• Creatinine clearance can be estimated using the Cockcroft-Gault equation for males: CLcr = (weight × [140 - age]) / (72 × serum creatinine), with females receiving 0.85 times this value 1

Pediatric Patients

• Creatinine clearance <30 mL/min/1.73 m²: 7 mg/kg (up to 300 mg) once daily 1
• Creatinine clearance estimation: CLcr = K × (body length/serum creatinine), where K = 0.55 for children >1 year and 0.45 for infants ≤1 year 1

Hemodialysis Patients

• Initial dose: 300 mg (or 7 mg/kg in pediatrics) every other day 1
• Post-dialysis supplementation: 300 mg (or 7 mg/kg) after each hemodialysis session 1
• Subsequent doses administered every other day 1

Pharmacokinetic Considerations in Renal Failure

• In patients with chronic renal failure undergoing continuous ambulatory peritoneal dialysis (CAPD), cefdinir half-life extends to 10.8-21.9 hours (compared to 1.5 hours in normal renal function) 4
• Approximately 1 mcg/mL of cefdinir remains in blood 24 hours after administration in CAPD patients, supporting once-daily dosing in severe renal impairment 4
• Serum concentrations are dose-dependent even in renal failure, with 100 mg daily and 200 mg daily regimens both well-tolerated for up to 14 consecutive days 4

Clinical Efficacy Evidence

• Cefdinir demonstrates approximately 90% clinical cure rates for acute community-acquired bacterial sinusitis, equivalent to amoxicillin-clavulanate 5
• Microbiologic eradication rates are similar between once-daily, twice-daily cefdinir, and comparator agents 5
• The drug provides excellent coverage against beta-lactamase-producing strains of Haemophilus influenzae and Moraxella catarrhalis, making it particularly useful in areas with elevated beta-lactamase production 2, 3

Common Pitfalls and Caveats

• Do not use once-daily dosing for skin infections in pediatric patients, as this has not been studied; always use twice-daily dosing (7 mg/kg every 12 hours) 1
• Diarrhea occurs in approximately 20% of patients but is typically mild and rarely requires discontinuation 5
• The oral suspension must be discarded after 10 days of storage at room temperature 1
• Failure to adjust dosing in renal impairment can lead to drug accumulation and increased adverse events 1, 4
• Cefdinir has minimal activity against penicillin-resistant Streptococcus pneumoniae and should not be relied upon as monotherapy in areas with high resistance rates 3