Cefoxitin Sodium

Cephamycin antibiotic Beta-lactam antibiotic (second-generation cephamycin)

Dosage & Administration Guidelines

Species Route Dose Frequency Duration & Clinical Notes
Dog IV or IM 20-30 mg/kg q8h Duration: 5-7 days or as clinically indicated
Notes: For surgical prophylaxis, administer 30 minutes before incision and may repeat intraoperatively if surgery >2 hours.
Cat IV or IM 20-30 mg/kg q8h Duration: 5-7 days or as clinically indicated
Notes: Use with caution in renal impairment; adjust dose.
Horse IV 20-30 mg/kg q6-8h Duration: 5-7 days or as clinically indicated
Notes: Administer slowly IV; IM administration may cause pain.
Cattle IV or IM 20-30 mg/kg q8h Duration: 5-7 days or as clinically indicated
Notes: Observe withdrawal times for milk and meat.
Small Ruminants (sheep/goats) IV or IM 20-30 mg/kg q8h Duration: 5-7 days or as clinically indicated
Notes: Extra-label use; observe withdrawal times.
Rabbit IV or IM 20-30 mg/kg q8h Duration: 5-7 days or as clinically indicated
Notes: Use cautiously in rabbits due to potential GI disturbances.
Birds/Poultry IM 20-30 mg/kg q8h Duration: 5-7 days or as clinically indicated
Notes: Extra-label; ensure adequate hydration.

Clinical Indications & Species Uses

General Indications
  • Treatment of infections caused by susceptible Gram-positive and Gram-negative aerobes and anaerobes
Dog (Canine)
  • Treatment of skin and soft tissue infections
  • Urinary tract infections
  • Respiratory tract infections
  • Intra-abdominal infections (e.g., peritonitis)
  • Septicemia
  • Prophylaxis in surgical procedures
Cat (Feline)
  • Treatment of skin and soft tissue infections
  • Urinary tract infections
  • Respiratory tract infections
  • Intra-abdominal infections
  • Septicemia
Horse (Equine)
  • Treatment of respiratory tract infections
  • Intra-abdominal infections
  • Septicemia
  • Prophylaxis in surgical procedures
Cattle (Bovine)
  • Treatment of respiratory tract infections
  • Metritis
  • Foot rot
  • Septicemia
Small Ruminants (Sheep / Goat)
  • Treatment of respiratory tract infections
  • Metritis
  • Septicemia
Rabbit & Small Mammals
  • Treatment of abscesses
  • Respiratory tract infections
  • Septicemia
Avian & Poultry
  • Treatment of colibacillosis
  • Respiratory tract infections
  • Septicemia
Exotic & Other Species
  • Treatment of bacterial infections in reptiles and small mammals

Pharmacology & Mechanism of Action

Drug Class: Cephamycin antibiotic | Pharmacological Group: Beta-lactam antibiotic (second-generation cephamycin)

Mechanism of Action: Cefoxitin is a cephamycin antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs) and interfering with peptidoglycan cross-linking. It is resistant to many beta-lactamases, including those produced by Staphylococcus spp. and some Gram-negative bacteria, providing activity against a broad spectrum of aerobic and anaerobic organisms.

Pharmacodynamics: Cefoxitin exhibits time-dependent bactericidal activity. It is effective against many Gram-positive and Gram-negative aerobes and anaerobes, including Bacteroides fragilis. It is stable to many beta-lactamases but not to extended-spectrum beta-lactamases (ESBLs) or AmpC beta-lactamases. Its spectrum includes Staphylococcus spp. (except MRSA), Streptococcus spp., Escherichia coli, Klebsiella spp., Proteus spp., and anaerobes.

⚑ Pharmacokinetics Summary

Absorption: Cefoxitin is not absorbed orally; it must be administered parenterally (IV or IM). After IM injection, peak plasma concentrations are achieved within 20-30 minutes.
Distribution: Cefoxitin distributes widely into body fluids and tissues, including pleural, peritoneal, and synovial fluids. It crosses the placenta but penetration into cerebrospinal fluid is poor unless meninges are inflamed.
Metabolism: Cefoxitin undergoes minimal hepatic metabolism; it is primarily eliminated unchanged by the kidneys.
Excretion: Cefoxitin is excreted primarily by the kidneys via glomerular filtration and tubular secretion. In animals with normal renal function, most of the dose is recovered in urine within 6 hours.
Half-Life: Dog: 0.5-1 hour; Horse: 0.5-1 hour; Cattle: 0.5-1 hour; Humans: 0.7-1 hour.
Bioavailability: Not orally bioavailable; IM bioavailability is approximately 100%.
Protein Binding: Approximately 50-70% bound to plasma proteins in various species.

Available Formulations & Strengths

Injectable Solution (powder for reconstitution) 1 g, 2 g, 10 g vials (IV or IM)

Contraindications & Clinical Warnings

Contraindications:
  • Known hypersensitivity to cefoxitin or other beta-lactam antibiotics (cephalosporins, penicillins)
  • Use in animals with a history of anaphylactic reactions to beta-lactams
Warnings & Clinical Precautions:
  • Use with caution in animals with renal impairment; adjust dose or extend dosing interval.
  • May cause injection site pain or phlebitis; administer IV slowly.
  • Prolonged use may result in overgrowth of non-susceptible organisms (e.g., Clostridium difficile).
  • Cross-reactivity with penicillins may occur; use with caution in penicillin-allergic animals.
  • Safety in pregnant or lactating animals has not been fully established; use only when clearly needed.
  • In food animals, observe withdrawal times; extra-label use requires veterinary oversight.

Adverse Effects & Reactions

Common:

  • Injection site pain
  • Phlebitis after IV administration
  • Gastrointestinal upset (vomiting, diarrhea)

Serious / Severe:

  • Anaphylaxis
  • Acute renal injury (especially with high doses or renal impairment)
  • Clostridium difficile-associated diarrhea
  • Seizures (with very high doses or in renal failure)

Rare:

  • Blood dyscrasias (neutropenia, thrombocytopenia)
  • Hepatotoxicity
  • Allergic interstitial nephritis

Key Drug Interactions

Interacting Drug / Class Clinical Effect & Mechanism Severity
Aminoglycosides (e.g., gentamicin) Additive nephrotoxicity; monitor renal function. High
Loop diuretics (e.g., furosemide) Increased risk of nephrotoxicity. Moderate
Probenecid Decreases renal tubular secretion of cefoxitin, increasing plasma concentrations and duration of action. Moderate
Warfarin and other anticoagulants May enhance anticoagulant effect; monitor coagulation parameters. Moderate

Overdose & Toxicity Management

Signs of Toxicity:

  • Neurological signs (seizures, tremors)
  • Gastrointestinal upset
  • Acute renal failure

Emergency Treatment Protocol: There is no specific antidote. Treatment is symptomatic and supportive. In cases of recent overdose, consider gastric lavage if oral (not applicable as parenteral). For parenteral overdose, discontinue drug, provide fluid therapy to enhance renal elimination, and manage seizures with diazepam or barbiturates. Monitor renal function and electrolytes. In severe cases, hemodialysis may be considered.

Food Animal Withdrawal Times

πŸ₯© Meat: 4 daysπŸ₯› Milk: 3 days

Withdrawal times are not established for all species; consult regulatory guidelines. For cattle, meat withdrawal is 4 days and milk 3 days when used according to label. For extra-label use, follow FARAD recommendations.

Storage, Handling & Regulatory Information

Storage Temperature: Store powder at controlled room temperature (20-25Β°C). Reconstituted solution is stable for 24 hours at room temperature and 7 days under refrigeration (2-8Β°C).

Handling & Special Conditions: Protect from freezing. Discard unused portions after stability period.

Dispensing Status: Prescription Required (Rx Only)

Approval Status: Approved for use in dogs, cats, and horses; not approved for food animals in the US, but may be used extra-label.

Extra-Label (Off-Label) Use: In the US, extra-label use in food animals is permitted under AMDUCA with veterinary oversight, requiring extended withdrawal times. In non-food animals, extra-label use is allowed.

Clinical Pearls & Practice Notes

πŸ’‘ Clinical Insights: Cefoxitin is a valuable antibiotic for mixed aerobic/anaerobic infections, particularly intra-abdominal and soft tissue infections. It is often used as a surgical prophylactic agent. Because of its short half-life, frequent dosing is required. It is not effective against MRSA, Enterococcus, or Pseudomonas. Use judiciously to minimize antimicrobial resistance. Monitor renal function in critically ill animals or those receiving concurrent nephrotoxic drugs.

References & Literature

  • πŸ“š Plumb's Veterinary Drug Handbook
  • πŸ“š Papich Veterinary Pharmacology and Therapeutics
  • πŸ“š Compendium of Veterinary Products (CVP)