CEFOTAXIME SODIUM
Clinical safety rating: safe
Probenecid may decrease cephalosporin excretion May cause diarrhea including Clostridium difficile-associated diarrhea.
Cefotaxime is a third-generation cephalosporin antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), specifically PBP-1A and PBP-3, leading to cell lysis and death.
| Metabolism | Cefotaxime is partially metabolized by esterases to desacetylcefotaxime, which has antimicrobial activity. It is not significantly metabolized by hepatic CYP450 enzymes. |
| Excretion | Renal (50-60% unchanged), biliary (5-10%), with approximately 20-30% metabolized to desacetylcefotaxime (also renally eliminated). Total renal elimination of parent drug and metabolite accounts for >80%. |
| Half-life | Terminal elimination half-life is 0.9-1.5 hours in adults with normal renal function; prolonged to 2.5-10 hours in renal impairment (CrCl <20 mL/min). In neonates, half-life is 3-6 hours. |
| Protein binding | 30-50% bound to serum proteins, primarily albumin. |
| Volume of Distribution | 0.2-0.4 L/kg (adults), indicating distribution primarily into extracellular fluid. Vd is higher in neonates (0.5-0.8 L/kg) and in critically ill patients (up to 0.6 L/kg). |
| Bioavailability | Intravenous: 100%. Intramuscular: approximately 95% within 30-60 minutes. Oral: Not bioavailable (administered parenterally only). |
| Onset of Action | Intravenous: Immediate (minutes). Intramuscular: Serum levels peak within 30 minutes, with clinical effect typically within 1-2 hours. Oral: Not applicable (parenteral only). |
| Duration of Action | Duration of antimicrobial activity is approximately 6-8 hours for most susceptible organisms, corresponding to dosing interval of 4-8 hours depending on infection severity. |
| Molecular Weight | 477.45 Da |
1-2 g IV/IM every 8 hours; maximum 12 g/day for severe infections.
| Dosage form | INJECTABLE |
| Renal impairment | GFR 10-30 mL/min: 1 g every 12 hours; GFR <10 mL/min: 1 g every 24 hours. |
| Liver impairment | No specific adjustment required; monitor for adverse effects in severe hepatic impairment (Child-Pugh class C). |
| Pediatric use | Neonates: 50 mg/kg IV/IM every 12 hours; Infants and children: 50-180 mg/kg/day IV/IM divided every 6-8 hours; maximum 12 g/day. |
| Geriatric use | Adjust dose based on renal function; consider lower initial dose due to age-related decreased clearance. |
| 1st trimester | Generally considered safe; crosses placenta; use only if clearly needed. No evidence of teratogenicity in animal studies. |
| 2nd trimester | Safe for use when indicated; no known fetal risk. |
| 3rd trimester | Safe for use; may cause positive Coombs test in neonate; no known adverse effects. |
Clinical note
Probenecid may decrease cephalosporin excretion May cause diarrhea including Clostridium difficile-associated diarrhea.
| FDA category | Human |
| Placental transfer | Crosses placenta readily; achieves therapeutic levels in fetal serum and amniotic fluid. |
| Breastfeeding | Enters breast milk in small amounts; considered compatible with breastfeeding. Monitor infant for diarrhea, rash, or candidiasis. |
■ FDA Black Box Warning
None.
| Common Effects | Diarrhea |
| Serious Effects |
Hypersensitivity to cefotaxime or any cephalosporinHypersensitivity to other beta-lactam antibiotics (e.g., penicillins)
| Precautions | Hypersensitivity reactions (including anaphylaxis) particularly in patients with penicillin allergy., Clostridioides difficile-associated diarrhea (CDAD)., Seizures may occur, especially with high doses or renal impairment., Prolonged use may result in superinfection or bacterial resistance., Renal function should be monitored in patients with renal impairment; dose adjustment required., Hemolytic anemia (rare). |
| Food/Dietary | Avoid alcohol: concurrent use may cause disulfiram-like reaction (flushing, headache, nausea, vomiting, tachycardia). No other significant food interactions. Maintain adequate hydration. |
Loading safety data…
| Lactation Rating | L2 (Safer) |
| Teratogenic Risk | No evidence of teratogenicity in animal studies. FDA Pregnancy Category B. No adequate studies in pregnant women. Risk in first trimester cannot be ruled out; use only if clearly needed. Second and third trimesters: no known fetal risk. |
| Fetal Monitoring | Monitor for hypersensitivity reactions, diarrhea (Clostridioides difficile infection), and superinfection. In prolonged therapy, monitor renal function and CBC with differential. No specific fetal monitoring required. |
| Fertility Effects | No known adverse effects on fertility in animal studies. No human data available on impact on fertility. |
| Clinical Pearls | Cefotaxime is a third-generation cephalosporin with good CNS penetration; use for empiric coverage of gram-negative meningitis. Monitor for cross-allergy in penicillin-allergic patients (approximately 10% risk). Administer IV over 3-5 minutes or as an infusion. Note that it does not cover Pseudomonas aeruginosa reliably (consider ceftazidime if Pseudomonas is suspected). Prolonged use may cause vitamin K deficiency and bleeding; monitor PT/INR. |
| Patient Advice | Complete the full course of therapy even if you feel better. · Report any signs of allergic reaction: rash, itching, difficulty breathing. · This medication may cause diarrhea; notify your doctor if it becomes severe or bloody. · Avoid alcohol during treatment and for 72 hours after last dose to prevent disulfiram-like reaction. · Take with food if gastrointestinal upset occurs. |