Cefdinir Dosage Calculator
Calculate cefdinir (Omnicef) doses for children by weight with once-daily or twice-daily options for otitis media, sinusitis, and pharyngitis.
Cefdinir Dosage Calculator
Evidence-based weight-adjusted dosing
How to Use This Calculator
Enter Weight
Type the child's weight in kilograms for accurate weight-based dosing.
Select Indication
Choose the infection type. All indications use the same 14 mg/kg/day dose.
Choose Frequency
Select once daily (full dose) or twice daily (divided dose) based on prescriber preference.
Review Dosing
Check per-dose amounts in mg and mL, plus the recommended frequency and max-dose limits.
How We Calculate
Cefdinir is a third-generation oral cephalosporin approved for pediatric use at 14 mg/kg/day for all standard indications including acute otitis media, sinusitis, pharyngitis, and uncomplicated skin infections. Per the FDA-approved labeling and AAP guidelines, the daily dose can be administered as a single daily dose or divided into two equal doses given every 12 hours.
The maximum daily dose is 600 mg regardless of weight. The two available suspension concentrations (125 mg/5 mL and 250 mg/5 mL) allow practical volume adjustments for different age groups. The higher concentration is preferred for older children to reduce the volume per dose.
Cefdinir is notable for causing harmless red-orange stool discoloration when taken concurrently with iron-containing products. This is a chelation reaction and does not affect drug efficacy. Parents should be counseled about this common finding to avoid unnecessary emergency visits.
Sources & References
- FDA Prescribing Information — Cefdinir (Omnicef) Capsules and Oral Suspension (fda.gov)
- AAP Red Book — Report of the Committee on Infectious Diseases (aap.org)
- Lexicomp Pediatric Drug Information — Cefdinir (wolterskluwer.com)
Data last verified:
Frequently Asked Questions
Cefdinir forms a non-absorbable complex with iron in the gastrointestinal tract, producing a reddish-orange discoloration of the stool. This occurs commonly when the child is also taking iron-fortified formula or iron supplements. The discoloration is completely harmless and resolves after the antibiotic course is completed. It can be alarming but is not blood in the stool.
Cefdinir can be taken with or without food. Taking it with food may reduce mild stomach upset but does not significantly affect absorption. However, cefdinir should NOT be taken at the same time as iron supplements or iron-fortified formula, as iron reduces cefdinir absorption by up to 80%. Separate iron products by at least 2 hours before or after the cefdinir dose.
Both regimens deliver the same total daily dose of 14 mg/kg and have equivalent clinical efficacy. Once-daily dosing improves compliance, especially for school-age children who might miss a midday dose. Twice-daily dosing provides more consistent drug levels and may be preferred for more severe infections. The prescriber will determine which frequency is most appropriate.
Cefdinir can generally be used in children with mild penicillin allergy (such as rash). The cross-reactivity between penicillins and third-generation cephalosporins like cefdinir is estimated at 1-2%, much lower than previously believed. However, children who experienced anaphylaxis or severe allergic reaction to penicillin should avoid all cephalosporins unless cleared by an allergist.
Reconstituted cefdinir suspension should be stored at room temperature (68-77°F / 20-25°C) and does NOT require refrigeration, which distinguishes it from many other antibiotic suspensions. Shake the bottle well before each dose. The reconstituted suspension is stable for 10 days. Discard any remaining medication after 10 days or at the end of the prescribed course.
For acute otitis media, the standard course is 5-10 days. For strep pharyngitis, 10 days is recommended to ensure eradication and prevent rheumatic fever. Sinusitis is typically treated for 10-14 days. Skin infections are usually treated for 10 days. Always complete the full prescribed course even if symptoms improve before the medication is finished.
Yes, cefdinir suspension can be mixed with a small amount of baby food, applesauce, or pudding immediately before giving the dose. It should not be mixed with iron-fortified infant formula. The mixture should be consumed immediately and not stored. The suspension has a strawberry cream flavor that most children tolerate well without needing to mix with food.
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