Cat · Felis catus · typical adult weight 2.50–7.00 kg
Trimethoprim-Sulfamethoxazole is used in cat for Pneumocystis (immunocompromised), UTI, skin infections, toxoplasmosis, Nocardia infections, Bacterial infections when oral not feasible. Routes documented in cat: PO, SC. A typical adult cat weighs 2.50–7.00 kg. ExoticRx lists 4 cited dose rules for Trimethoprim-Sulfamethoxazole in cat, drawn from published veterinary references. Verify against current literature before clinical use.
Trade names: Bactrim, TMS
| Route | Dose | Frequency | Duration | Indication | Evidence | Source |
|---|---|---|---|---|---|---|
| PO | 15–30 mg/kg | q12h | 21 days | Pneumocystis (immunocompromised) | Weak | Plumb's Veterinary Drug Handbook, 9th Ed |
| PO | 15–30 mg/kg | q12h | 14-21 days | UTI, skin infections, toxoplasmosis | Strong | Plumb's Veterinary Drug Handbook, 9th Ed |
| PO | 15–30 mg/kg | q12h | 6-12 weeks | Nocardia infections | Moderate | Plumb's Veterinary Drug Handbook, 9th Ed |
| SC | 15–30 mg/kg | q12h | Until oral feasible | Bacterial infections when oral not feasible | Moderate | Plumb's Veterinary Drug Handbook, 9th Ed |
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These ranges are per kg. Enter your cat's weight to get the precise dose and draw-up volume — unit and concentration math done for you.
Sequential blockade of folate synthesis: sulfamethoxazole inhibits dihydropteroate synthase; trimethoprim inhibits dihydrofolate reductase.
May cause keratoconjunctivitis sicca (KCS) in dogs with prolonged use. Can cause bone marrow suppression. Avoid in animals with hepatic disease. Adequate hydration required.
Species-specific contraindications and adverse-reaction reports for cat may differ from canine / feline reference data — consult the primary citations listed with each rule.
Why a species-specific page? Trimethoprim-Sulfamethoxazole pharmacokinetics differ across species: dose ranges, intervals, and route preferences are not interchangeable. Cross-extrapolation from canine doses is unsafe in cat — the rules above are the citations specific to this species, not generic recommendations.
Sourced from published veterinary references; awaiting credentialed clinical reviewer. See our editorial process. Reference only — not veterinary advice.