Ceftiofur Sodium

Overview

Ceftiofur sodium (Naxcel®, Ceftiflex®) is a veterinary-only third-generation cephalosporin antibiotic used in dogs and cats for treatment of susceptible bacterial infections. In canine medicine, it is primarily labeled for treatment of urinary tract infections (UTIs) associated with Escherichia coli and Proteus mirabilis.

Like other third-generation cephalosporins, ceftiofur has a broad spectrum of activity against many gram-positive and gram-negative pathogens and is considered a bactericidal, time-dependent antimicrobial. In dogs, systemic concentrations are limited, and clinically useful levels are achieved primarily in urine.

Mechanism of Action (MOA): Ceftiofur inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins involved in the final stage of peptidoglycan formation. After administration, it is rapidly metabolized to desfuroylceftiofur, an active metabolite that retains antimicrobial activity against susceptible organisms. This disruption of cell wall synthesis results in bacterial lysis and death.

Indications

Ceftiofur is used in dogs and cats for treatment of infections caused by bacteria susceptible to third-generation cephalosporins. Clinical use is most common in urinary infections and systemic infections where parenteral antibiotic therapy is required.

• Urinary tract infections (UTIs): FDA-approved in dogs for UTIs associated with Escherichia coli and Proteus mirabilis.
• Susceptible bacterial infections: Used extra-label in dogs and cats for infections caused by susceptible gram-positive and gram-negative organisms.
• Neonatal septicemia: May be used as part of treatment protocols for suspected bacterial septicemia in neonatal puppies and kittens.
• Empirical therapy for serious infections: Because of its broad antimicrobial spectrum, ceftiofur may be selected when parenteral therapy is needed and culture results are pending.

Dosage (Reference)

Dog

In dogs, ceftiofur is administered parenterally, most commonly by subcutaneous injection. Therapeutic concentrations are primarily achieved in urine, which explains its labeled indication for urinary tract infections.

Cat

In cats, ceftiofur is used extra-label for treatment of susceptible bacterial infections requiring parenteral antimicrobial therapy.

Warnings & Precautions

Ceftiofur is generally well tolerated, but as with other cephalosporins, certain precautions should be considered when selecting patients and monitoring therapy.

• Hypersensitivity reactions: Cephalosporins are contraindicated in animals with a known hypersensitivity to cephalosporin antibiotics.
• Cross-reactivity with penicillins: Some patients allergic to penicillins may also react to cephalosporins because both belong to the beta-lactam class.
• Injection site reactions: Pain or local irritation may occur after intramuscular injection, particularly in small animals.
• Antimicrobial stewardship: Third-generation cephalosporins are considered critically important antimicrobials in human medicine and should be reserved for infections where appropriate.
• Drug identification: Ceftiofur exists in multiple formulations (e.g., sodium, hydrochloride, crystalline free acid), which may differ in pharmacokinetics and dosing.

Drug Interactions

Most interactions with ceftiofur are related to additive nephrotoxicity or changes in renal drug elimination when combined with other medications.

• Aminoglycosides (e.g., amikacin, gentamicin): Concurrent use may increase the risk of nephrotoxicity; administer drugs separately and monitor renal function.
• Nephrotoxic drugs (e.g., amphotericin B, furosemide, contrast agents): May increase the risk of kidney injury when used concurrently.
• Probenecid: May inhibit renal tubular secretion of cephalosporins, increasing serum concentrations and prolonging drug half-life.

Side Effects & Overdose

Side Effects

Adverse reactions to ceftiofur are generally uncommon but may occur in sensitive patients or with prolonged therapy.

• Hypersensitivity reactions: Allergic responses such as rash, fever, or anaphylaxis may occur in sensitized animals.
• Gastrointestinal effects: Diarrhea or mild gastrointestinal upset may occur due to alteration of intestinal microbiota.
• Injection site pain: Particularly reported following intramuscular administration.
• Hematologic effects: Rare cases of granulocytopenia or thrombocytopenia have been reported.

Overdose

Cephalosporins have a relatively wide safety margin. Overdose is unlikely to produce life-threatening toxicity but may cause gastrointestinal or hematologic abnormalities.

• Gastrointestinal upset: Vomiting or diarrhea may occur after excessive dosing.
• Hematologic abnormalities: Prolonged high-dose exposure has been associated with thrombocytopenia or anemia in dogs.
• Management: Treatment is primarily supportive, including discontinuation of the drug and symptomatic care.

Key Notes

Practical clinical points that help optimize safe and effective use of ceftiofur in dogs and cats:

• Veterinary-only antibiotic: Ceftiofur is developed specifically for veterinary medicine and is not available as a human drug product.
• Injection-only medication: The drug must be administered by injection; it is not effective when given orally.
• Urinary concentrations: In dogs, clinically useful drug concentrations are achieved primarily in urine, supporting its use for UTIs.
• Broad antimicrobial spectrum: Active against many gram-positive and gram-negative organisms but not effective against methicillin-resistant staphylococci or enterococci.
• Culture-guided therapy preferred: Whenever possible, therapy should be based on bacterial culture and susceptibility testing.
• Injection technique: Proper injection technique and aseptic preparation help minimize injection site reactions.