What is the appropriate dose of cefdinir suspension (125 mg per 5 mL) for a 21‑lb (≈9.5 kg) child per administration?

Cefdinir Dosing for a 21-lb (9.5 kg) Child

Give 2.5 mL of cefdinir 125 mg/5 mL suspension every 12 hours (twice daily). 1

Weight-Based Calculation

• A 21-lb child weighs approximately 9.5 kg, which falls into the 9 kg/20 lb dosing category in the FDA-approved pediatric dosing chart. 1
• The standard pediatric dose is 7 mg/kg every 12 hours for twice-daily dosing. 2, 1
• For a 9 kg child: 9 kg × 7 mg/kg = 63 mg per dose, which corresponds to 2.5 mL of the 125 mg/5 mL suspension given every 12 hours. 1

Dosing Regimen Options

Twice-daily dosing (recommended for most infections):

• 2.5 mL every 12 hours using the 125 mg/5 mL suspension 1
• Total daily dose = 126 mg/day (approximately 14 mg/kg/day) 1

Once-daily dosing (alternative for specific infections):

• 5 mL once daily (14 mg/kg every 24 hours) may be used for acute otitis media, sinusitis, or pharyngitis/tonsillitis 2, 1
• Once-daily dosing has not been studied for skin infections, so twice-daily administration is required for uncomplicated skin and skin structure infections 1

Treatment Duration

• Acute otitis media: 5–10 days 1
• Acute maxillary sinusitis: 10 days 1
• Pharyngitis/tonsillitis: 5–10 days 1
• Uncomplicated skin infections: 10 days (must use twice-daily dosing) 1

Administration Instructions

• Cefdinir suspension may be given without regard to meals. 1
• Shake the bottle well before each dose. 1
• The suspension remains stable at room temperature for 10 days after mixing; discard any unused portion after this time. 1

Clinical Context

• Cefdinir is positioned as an alternative agent when first-line therapy (high-dose amoxicillin or amoxicillin-clavulanate) cannot be used, particularly for β-lactamase-producing Haemophilus influenzae in community-acquired pneumonia. 2
• It provides good coverage against common respiratory pathogens including H. influenzae, Moraxella catarrhalis, and penicillin-susceptible Streptococcus pneumoniae. 3, 4
• Cefdinir is stable against β-lactamase hydrolysis, making it effective against β-lactamase-producing strains. 4

Common Pitfall to Avoid

• Do not use once-daily dosing for skin infections—the FDA label explicitly states that once-daily dosing has not been studied for this indication and twice-daily administration is required. 1
• For penicillin-resistant S. pneumoniae, cefdinir at standard doses (14 mg/kg/day) may be inadequate; even higher doses (25 mg/kg/day) showed suboptimal pharmacodynamics against nonsusceptible strains. 5 In such cases, consider alternative agents or higher-dose amoxicillin (90 mg/kg/day). 2

Tolerability

• Diarrhea is the most common adverse effect, occurring in approximately 12.5% of pediatric patients. 6
• The oral suspension has demonstrated superior taste and palatability compared to other oral antimicrobials, which may improve adherence. 3, 4