Cefdinir Dosing for Streptococcal Pharyngitis in a 10-Year-Old
For a 10-year-old child weighing 78 pounds (35.4 kg) with streptococcal pharyngitis, administer cefdinir 7 mg/kg twice daily for 5 days, which equals approximately 250 mg (5 mL of 250 mg/5 mL suspension) twice daily. 1
Weight-Based Dose Calculation
- The child weighs 78 pounds, which converts to 35.4 kg. 1
- Using the FDA-approved dosing of 7 mg/kg every 12 hours, the calculated dose is 35.4 kg × 7 mg/kg = 248 mg per dose, rounded to 250 mg twice daily. 1
- This translates to 5 mL of the 250 mg/5 mL suspension twice daily for ease of administration. 1
- The total daily dose is 500 mg, which is well below the maximum of 600 mg per day for pediatric patients. 1
Treatment Duration: 5 Days vs. 10 Days
A 5-day course of cefdinir is equally effective as a 10-day course for streptococcal pharyngitis and offers superior bacteriologic eradication compared to 10 days of penicillin V. 2, 3
- Clinical trials demonstrate that cefdinir 7 mg/kg twice daily for 5 days achieves a 90% bacteriologic eradication rate versus 72% with penicillin V for 10 days (P < 0.001). 3
- Clinical cure rates are equivalent between 5-day cefdinir (92%) and 10-day penicillin V (91%), with no difference in adverse event rates. 3
- The FDA label approves both 5-day and 10-day regimens for pharyngitis/tonsillitis, giving clinicians flexibility based on adherence concerns. 1
Alternative Once-Daily Dosing Option
- Cefdinir may alternatively be dosed as 14 mg/kg once daily (approximately 500 mg or 10 mL of 250 mg/5 mL suspension once daily) for 10 days, which has equivalent efficacy to twice-daily dosing. 1, 2
- Once-daily dosing improves adherence but requires a 10-day course rather than 5 days. 1
Clinical Context: Why Cefdinir for Strep Throat?
- Cefdinir is an appropriate alternative to penicillin or amoxicillin for Group A streptococcal pharyngitis, particularly in patients with penicillin allergy (non-anaphylactic) or recent treatment failure. 4, 5
- It provides excellent coverage against Streptococcus pyogenes and is stable against beta-lactamases, though this is less relevant for strep throat since S. pyogenes does not produce beta-lactamases. 5, 6
- The drug has superior palatability compared to penicillin V, which may improve adherence in pediatric patients. 5
Important Caveats and Monitoring
- Red stools may occur if the child is taking iron supplements or iron-fortified formula, due to a benign drug-iron interaction that produces heme-negative red stools; this is reversible upon discontinuation and does not require workup. 7
- Diarrhea is the most common adverse effect, occurring in approximately 12.5% of patients, similar to penicillin V (13.6%). 3
- Cefdinir should be administered without regard to meals, though absorption is slightly reduced with high-fat meals. 1
- After mixing the suspension, it remains stable at room temperature for 10 days only; any unused portion must be discarded after this period. 1
When Cefdinir Is NOT First-Line
- Amoxicillin remains the preferred first-line agent for uncomplicated streptococcal pharyngitis at 50–75 mg/kg/day in two divided doses for 10 days (maximum 1,000 mg per dose). 8
- Cefdinir is reserved for patients with non-anaphylactic penicillin allergy, recent amoxicillin failure, or when adherence concerns favor a shorter 5-day course. 4, 8
- For true IgE-mediated (Type I) penicillin allergy, clindamycin or azithromycin are preferred over cephalosporins due to potential cross-reactivity. 8, 9