Ceftazidime: veterinary dose and monograph

At a glance

Drug class

Antibiotic

Also known as

Fortum, Ceftaz, Tazidime

Species with doses

Dogs, Cats, Horses and Reptiles

General dose range

25–30 mg/kg IV q6–8h — check the species tables for the indication

Routes

IV, IM

Last reviewed

1 October 2026

Indications

• Pseudomonas aeruginosa infections (otitis, wounds, sepsis, pneumonia)
• Serious resistant Gram-negative infections (sepsis, peritonitis)
• Avian/reptile systemic Gram-negative infection
• Febrile neutropenia (empiric, with culture)

Ceftazidime dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Dogs

• Susceptible infection (incl. Pseudomonas): Papich 5e: 25 mg/kg q8h IV, SC or IM. Plumb’s p.227: Gram-negative infections 25 mg/kg IM or SC q8–12h (Kruth); soft tissue 30–50 mg/kg IV/IM q8–12h; sepsis 15–30 mg/kg IV/IM q6–8h (Greene & Watson). Time-dependent killing — frequent dosing or CRI.
• Constant-rate infusion: Papich 5e (dogs and cats): loading dose 2 mg/kg, then 2 mg/kg/h in IV fluids.

Cats

• Susceptible Gram-negative infection: Papich 5e: 25 mg/kg q8h IV, SC or IM. Plumb’s p.227 (Greene & Watson 1998): 25–30 mg/kg IV, IM or IO q8–12h.

Horses

• Susceptible infection: Papich 5e: horses 20 mg/kg q8h IV or IM. (The previous 25–50 mg/kg q6–8h had no source.)

Birds

• No reference dose for this species: Neither Papich 5e nor Plumb’s gives a ceftazidime dose for birds; the previous 75–100 mg/kg row had no verifiable source.

Reptiles

• Gram-negative / Pseudomonas infection: Plumb's p.227: most species 20 mg/kg IM/SC q72h (Lewbart 2001); snakes with Enterobacteriaceae/Pseudomonas 20 mg/kg IM q72h at 30°C (Klingenberg); chelonians 50 mg/kg IM q24h (Johnson 2002). A first-line reptile antibiotic for Gram-negative/Pseudomonas respiratory & systemic infection.

Contraindications

Beta-lactam (penicillin/cephalosporin) hypersensitivity. Reduce dose/frequency in significant renal impairment (renally cleared). Not for routine first-line use — preserve antipseudomonal activity. Known hypersensitivity.

Species-specific warnings

Horses: Valuable for neonatal foal Gram-negative sepsis; dose to the organism MIC and monitor.

Adverse effects

• Injection-site pain/phlebitis
• GI upset, diarrhoea
• Hypersensitivity (rash, rare anaphylaxis)
• Rare nephrotoxicity / neurotoxicity (high dose, renal failure)

Drug interactions

• Aminoglycosides: synergistic against Pseudomonas but physically incompatible in one syringe
• Other nephrotoxins: additive renal risk in renal impairment
• Chloramphenicol: possible antagonism (bacteriostatic vs bactericidal)
• Probenecid has less effect than on other beta-lactams

Pregnancy and lactation

Cephalosporins are generally considered safe in pregnancy/lactation; widely used class with a good safety record.

Monitoring

• Culture & sensitivity (confirm Pseudomonas/resistant organism before use)
• Renal function on prolonged/high-dose therapy
• Hypersensitivity at first dose
• Clinical response at 48–72 h

Toxicity and overdose

Very wide margin — acute toxicity essentially limited to hypersensitivity. High doses with renal failure can cause CNS signs (twitching, seizures) from accumulation. Otherwise well tolerated.

Management: No specific antidote — supportive. Treat anaphylaxis (epinephrine, antihistamine, corticosteroid). Reduce dose and support renal clearance with fluids; haemodialysis removes the drug in severe renal failure.

Clinical pearls

• The cephalosporin to reach for against Pseudomonas — but reserve it (and confirm by culture) to preserve activity
• Time-dependent killing: dose frequently (q6–8h) or use a CRI rather than large infrequent boluses
• Birds clear it fast — they need higher mg/kg and q8h dosing
• Weaker against Gram-positives than 1st/2nd-gen cephalosporins — not an all-purpose drug
• Reduce dose in renal impairment to avoid CNS accumulation toxicity

Mechanism of action

Beta-lactam that binds penicillin-binding proteins (PBPs), inhibiting peptidoglycan cross-linking and cell-wall synthesis — bactericidal, time-dependent. Its aminothiazolyl/carboxypropyl side chains confer stability against many Gram-negative beta-lactamases and excellent outer-membrane penetration, giving the antipseudomonal Gram-negative reach that defines it (with comparatively weaker Gram-positive activity).

Formulations and products

• Ceftazidime 1 g dry-powder vial — reconstitute per label
• Ceftazidime powder reconstituted to 280 mg/mL (0.5 / 1 / 2 / 6 g vials — Papich 5e p.157)
• Fortum — 250 mg / 1 g / 2 g vial, Injection (reconstitute) (human-label)
• Ceftaz — 1 g vial, Injection (human-label)

Storage

Dry powder vial: 15–25 °C, protect from light. Reconstituted solution: refrigerate and use within 24 h (releases CO2 on reconstitution — vent the vial). Frozen reconstituted product per label.

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

Other antibiotics

• Cefotaxime
• Cefovecin
• Cefpodoxime proxetil
• Cefquinome
• Ceftiofur
• Ceftriaxone
• Cefuroxime
• Cephalexin

Frequently asked questions