cefdinir
Brand: Omnicef
Prototype: ceftriaxone
Drug Class: third-generation cephalosporin
Drug Family: antibiotic
Subclass: oral third-generation cephalosporin
Organ Systems: infectious-disease
Mechanism of Action
Inhibits bacterial cell wall synthesis via PBP binding; oral third-generation agent with good activity against H. influenzae, M. catarrhalis, and S. pneumoniae.
penicillin-binding proteins (PBPs)
Indications
- community-acquired pneumonia
- acute exacerbation of chronic bronchitis
- sinusitis
- otitis media
- skin and soft tissue infections
- pharyngitis/tonsillitis
Contraindications
- cephalosporin hypersensitivity
Adverse Effects
Common
- diarrhea
- nausea
- reddish-brown stools (due to iron binding, not blood)
- vaginitis
Serious
- anaphylaxis
- C. difficile colitis
- serum sickness-like reaction
Pharmacokinetics (ADME)
| Absorption | 21–25% bioavailability (fasting); food slightly increases absorption |
| Distribution | widely distributed; moderate tissue penetration |
| Metabolism | minimal |
| Excretion | renal (unchanged) and fecal |
| Half-life | 1.7 hours |
| Onset | rapid |
| Peak | 2–4 hours |
| Duration | 12–24 hours |
| Protein Binding | 60–70% |
| Vd | moderate |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| iron supplements/antacids | chelation reduces cefdinir absorption by up to 80%; separate administration by 2 hours | moderate |
| probenecid | reduces renal excretion, increases cefdinir levels | minor |
Nursing Considerations
- Advise patients that stools may turn red-brown due to formation of a non-absorbable iron-cefdinir complex; reassure this is benign and not blood.
- Separate administration from iron-containing products, antacids, or multivitamins by at least 2 hours to preserve absorption.
- Monitor for signs of secondary vaginal yeast infection in female patients.
- Assess for cephalosporin or penicillin allergy before administration.
Clinical Pearls
- Cefdinir is widely used in pediatric practice for otitis media and sinusitis because it is available as a palatable suspension and has a twice-daily dosing schedule.
- The characteristic red-brown stool discoloration is benign and results from chelation with dietary iron, not GI bleeding.
Safety Profile
Pregnancy generally-safe
Lactation use-with-caution
Renal Adjustment Required
Hepatic Adjustment Not required
TDM Not required
Concordance Terms
Cross-referenced clinical concepts — click any term to see all content where it appears.