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. |
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 | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Probenecid may decrease cephalosporin excretion May cause diarrhea including Clostridium difficile-associated diarrhea.
| FDA category | Human |
| Breastfeeding | Excreted into human breast milk in low concentrations (M/P ratio approximately 0.02-0.05). Considered compatible with breastfeeding; monitor infant for diarrhea, rash, or candidiasis. |
| 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. |
■ FDA Black Box Warning
None.
| Common Effects | Diarrhea |
| Serious Effects |
["Hypersensitivity to cefotaxime or any cephalosporin antibiotic.","Hypersensitivity to penicillins (cross-sensitivity may occur)."]
| 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. |
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| 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. |