CEFDINIR
Clinical safety rating: safe
Human studies have proved safety
Cefdinir is a third-generation cephalosporin antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), thereby inhibiting peptidoglycan cross-linking, leading to cell lysis and death.
| Metabolism | Cefdinir is not significantly metabolized; it is primarily excreted unchanged in the urine via tubular secretion and glomerular filtration. Minimal renal metabolism occurs. |
| Excretion | Renal: 90-95% unchanged in urine via glomerular filtration and tubular secretion. Biliary/fecal: <1% biliary, <5% fecal. |
| Half-life | Terminal elimination half-life: 1.7 ± 0.6 hours (range 1.4-2.3 h) in healthy adults; prolonged in renal impairment (e.g., up to 8 hours in end-stage renal disease). |
| Protein binding | ~60-70% bound to plasma proteins (primarily albumin). |
| Volume of Distribution | Vd: 0.35 ± 0.12 L/kg (approximately 24 L in adults), indicating distribution primarily into extracellular fluid. |
| Bioavailability | Oral: 16-25% (mean ~20%) after capsule; 91% for suspension due to slower gastric emptying; absorption increased with food; no IV formulation. |
| Onset of Action | Oral: peak serum concentrations at 2-4 hours; time to clinical effect typically within 24 hours for susceptible infections. |
| Duration of Action | Duration ~12 hours; recommended dosing every 12 hours to maintain therapeutic levels above MIC for susceptible pathogens. |
| Molecular Weight | 395.41 |
300 mg orally twice daily for 5-10 days, or 600 mg orally once daily for 10 days.
| Dosage form | FOR SUSPENSION |
| Renal impairment | For CrCl 30-59 mL/min: 300 mg twice daily or 600 mg once daily. For CrCl <30 mL/min or hemodialysis: 300 mg once daily or 7 mg/kg once daily (max 300 mg). For peritoneal dialysis: 300 mg once daily. |
| Liver impairment | No dose adjustment required for hepatic impairment as cefdinir is primarily excreted renally. |
| Pediatric use | For children 6 months to 12 years: 7 mg/kg orally every 12 hours or 14 mg/kg orally once daily for 5-10 days (max 600 mg/day). For acute bacterial otitis media and acute maxillary sinusitis: 7 mg/kg every 12 hours for 5-10 days. |
| Geriatric use | Dose adjustment based on renal function; monitor CrCl and reduce dose accordingly. No specific geriatric dose changes aside from renal considerations. |
| 1st trimester | Use only if clearly needed; no well-controlled studies in humans, but animal studies have not shown fetal harm. Cefdinir crosses the placenta and achieves low to moderate fetal concentrations. |
| 2nd trimester | Generally considered safe; no evidence of teratogenicity in animal studies. Use if benefit outweighs risk. |
| 3rd trimester | Generally considered safe; no known risk of neonatal adverse effects. Use if indicated. |
Clinical note
Antacids and iron supplements decrease absorption May cause red stools due to interaction with iron.
| Placental transfer | Cefdinir crosses the placenta; fetal serum concentrations are approximately 10-20% of maternal serum concentrations. Evidence is based on human case reports and animal studies. |
| Breastfeeding | Cefdinir is excreted into breast milk in very small amounts (less than 0.1% of maternal dose). It is unlikely to cause adverse effects in the nursing infant. However, caution is advised in infants with known hypersensitivity to cephalosporins or if the infant is premature or has underlying gastrointestinal disease. |
■ FDA Black Box Warning
No FDA black box warning.
| Common Effects | Diarrhea |
| Serious Effects |
Hypersensitivity to cefdinir or any other cephalosporin antibioticDocumented immediate-type hypersensitivity reaction (e.g., anaphylaxis) to penicillins or other beta-lactams (cross-sensitivity)
| Precautions | Hypersensitivity reactions (anaphylaxis, Stevens-Johnson syndrome) have been reported; discontinue cefdinir if an allergic reaction occurs., Clostridioides difficile-associated diarrhea (CDAD) may occur; consider if diarrhea develops., Dose adjustment required in renal impairment (CrCl <30 mL/min)., May cause seizure activity in patients with renal impairment or CNS disorders., Prolonged use may result in superinfection. |
| Food/Dietary | Avoid concurrent administration with iron supplements, iron-fortified infant formula, or multivitamins containing iron, as they reduce cefdinir absorption by up to 80%. Separate by at least 2 hours. Antiulcer drugs (e.g., antacids containing magnesium or aluminum) may also reduce absorption, so take cefdinir 2 hours before or after such products. |
Loading safety data…
| Lactation Rating | L2 (Probably Compatible) |
| Teratogenic Risk | FDA Pregnancy Category B. No evidence of teratogenicity in animal studies. Insufficient human data; use only if clearly needed. Avoid in first trimester unless essential. |
| Fetal Monitoring | No specific monitoring required beyond standard pregnancy care. Monitor for maternal adverse effects (GI disturbances, rash) and fetal wellbeing via routine ultrasound. |
| Fertility Effects | No known adverse effects on fertility in animal studies. Human data lacking. |
| Clinical Pearls | Cefdinir is a third-generation oral cephalosporin with activity against many Gram-positive and Gram-negative organisms. It is FDA-approved for acute otitis media, community-acquired pneumonia, acute sinusitis, pharyngitis/tonsillitis, and uncomplicated skin and soft tissue infections. Note that cefdinir may cause a false-positive urine glucose test (Clinitest) but not with glucose oxidase methods. It can also cause harmless red stools due to non-absorbable cefdinir-iron complex. Patients with penicillin allergy may have cross-reactivity, so use caution. Dose adjustment is required for creatinine clearance <30 mL/min (300 mg once daily instead of standard dosing). |
| Patient Advice | Take cefdinir exactly as prescribed, with or without food; but avoid taking with iron supplements or iron-fortified foods within 2 hours as it reduces absorption. · Complete the full course even if you feel better to prevent resistance. · You may experience mild diarrhea (common), but contact your doctor if severe watery stools, abdominal pain, or fever occurs (possible C. difficile). · Cefdinir can cause a harmless red or orange discoloration of stools; this is not blood. · Inform your doctor if you have a history of penicillin allergy or kidney problems. · Do not use cefdinir if you are allergic to cephalosporins or penicillins. |