What is the appropriate cefdinir dosing regimen for adults, adolescents, and children, including adjustments for impaired renal function and administration instructions?

Cefdinir Dosing Regimen

Cefdinir is dosed at 300 mg twice daily or 600 mg once daily in adults and adolescents, 14 mg/kg/day (maximum 600 mg/day) in one or two divided doses for pediatric patients aged 6 months through 12 years, with dose reduction to 300 mg once daily (or 7 mg/kg once daily in children) for patients with creatinine clearance <30 mL/min. 1

Adult and Adolescent Dosing

• Standard dosing for adults and adolescents is 300 mg orally twice daily or 600 mg orally once daily for respiratory tract infections and uncomplicated skin and skin structure infections. 1, 2
• The total daily dose is 600 mg regardless of whether administered once or twice daily. 1
• Treatment duration is typically 5 to 10 days depending on the infection type and severity. 1, 2
• Cefdinir may be administered without regard to meals, though administration with food may improve gastrointestinal tolerability. 1

Pediatric Dosing (Age 6 Months Through 12 Years)

• The total daily dose for all infections is 14 mg/kg, up to a maximum of 600 mg per day. 1
• Dosing can be administered as 7 mg/kg every 12 hours OR 14 mg/kg once daily for most infections. 1, 2

Indication-Specific Pediatric Dosing:

• Acute bacterial otitis media: 7 mg/kg q12h for 5-10 days OR 14 mg/kg q24h for 10 days 1
• Acute maxillary sinusitis: 7 mg/kg q12h for 10 days OR 14 mg/kg q24h for 10 days 1
• Pharyngitis/tonsillitis: 7 mg/kg q12h for 5-10 days OR 14 mg/kg q24h for 10 days 1
• Uncomplicated skin and skin structure infections: 7 mg/kg q12h for 10 days (once-daily dosing has not been studied for skin infections) 1

Weight-Based Pediatric Dosing Examples:

• 9 kg (20 lbs): 2.5 mL (125 mg/5 mL suspension) q12h or 5 mL q24h 1
• 18 kg (40 lbs): 5 mL (125 mg/5 mL) q12h or 10 mL q24h 1
• 27 kg (60 lbs): 7.5 mL (125 mg/5 mL) q12h or 15 mL q24h 1
• 36 kg (80 lbs): 10 mL (125 mg/5 mL) q12h or 20 mL q24h 1
• ≥43 kg (95 lbs): Maximum adult dose of 600 mg/day (12 mL of 125 mg/5 mL q12h or 24 mL q24h) 1

Renal Impairment Adjustments

Adults with Renal Insufficiency:

• For creatinine clearance <30 mL/min: reduce dose to 300 mg once daily. 1
• Creatinine clearance can be estimated using the Cockcroft-Gault equation for adults:
  • Males: CLcr = (weight in kg) × (140 – age) / [(72) × (serum creatinine in mg/dL)] 1
  • Females: CLcr = 0.85 × above value 1

Pediatric Patients with Renal Insufficiency:

• For creatinine clearance <30 mL/min/1.73 m²: reduce dose to 7 mg/kg (up to 300 mg) once daily. 1
• Pediatric creatinine clearance estimation:
  • CLcr = K × (body length or height in cm) / (serum creatinine in mg/dL) 1
  • K = 0.55 for children >1 year; K = 0.45 for infants ≤1 year 1

Hemodialysis Patients:

• Initial dosing: 300 mg (or 7 mg/kg in children) every other day. 1
• At the conclusion of each hemodialysis session: administer 300 mg (or 7 mg/kg). 1
• Subsequent maintenance doses: 300 mg (or 7 mg/kg) every other day. 1
• Hemodialysis removes cefdinir from the body, necessitating post-dialysis supplementation. 1

Oral Suspension Preparation

• 125 mg/5 mL suspension: Add 38 mL (for 60 mL bottle) or 63 mL (for 100 mL bottle) of water in two portions; shake well after each addition 1
• 250 mg/5 mL suspension: Add 38 mL (for 60 mL bottle) or 63 mL (for 100 mL bottle) of water in two portions; shake well after each addition 1
• After reconstitution, store at room temperature (25°C/77°F) in a tightly closed container. 1
• Shake well before each administration; discard unused suspension after 10 days. 1

Clinical Considerations and Caveats

• Cefdinir provides excellent coverage against β-lactamase-producing strains of Haemophilus influenzae and Moraxella catarrhalis, making it particularly useful in areas with high β-lactamase prevalence. 2, 3
• The drug has good activity against penicillin-susceptible Streptococcus pneumoniae but may have reduced efficacy against highly penicillin-resistant strains. 2, 3
• Once-daily dosing is as effective as twice-daily dosing for respiratory infections (10-day course), offering improved convenience and compliance. 1, 2
• For skin infections, twice-daily dosing is required as once-daily regimens have not been adequately studied for this indication. 1
• Diarrhea is the most common adverse event (10% in adults), occurring more frequently than with some comparators like cephalexin (4%). 4
• Cefdinir suspension has demonstrated superior taste and palatability compared to other oral antimicrobials in pediatric populations, potentially improving adherence. 2, 3
• Do not use cefdinir as first-line empiric therapy for suspected MRSA infections, as cephalosporins lack reliable activity against methicillin-resistant Staphylococcus aureus. 4