Cat · Felis catus · typical adult weight 2.50–7.00 kg
Pyrimethamine is dosed at 0.25–0.5 mg/kg PO q12h in cats, per Foster SF, Martin P. Lower respiratory tract infections in cats: Reaching beyond empirical therapy. J Feline Med Surg. 2011;13:313-332. doi:10.1016/j.jfms.2011.06.001 — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.1127 (2026-08-01).. Pyrimethamine is used in cats for Toxoplasmosis. Routes documented in cats: PO. A typical adult cat weighs 2.50–7.00 kg. ExoticRx lists 1 cited dose rule for Pyrimethamine in cats, drawn from published veterinary references. Verify against current literature before clinical use.
US trade names: Daraprim
| Route | Dose | Frequency | Duration | Indication | Evidence | Source |
|---|---|---|---|---|---|---|
| PO | 0.25–0.5 mg/kg | q12h | 14-28 days with trimethoprim-sulfa; taper to q24h after clinical improvement | Toxoplasmosis | Moderate | Foster SF, Martin P. Lower respiratory tract infections in cats: Reaching beyond empirical therapy. J Feline Med Surg. 2011;13:313-332. — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.1127 (2026-08-01). |
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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.
Inhibits dihydrofolate reductase in protozoa, blocking folic acid synthesis required for DNA replication. Synergistic with sulfonamides.
Bone marrow suppression possible — monitor CBC. Supplement with folinic acid (leucovorin). Teratogenic. Do not use in pregnant animals.
Species-specific contraindications and adverse-reaction reports for cats may differ from canine / feline reference data — consult the primary citations listed with each rule.
Pyrimethamine dose range in cats, with cited source references: PO 0.25–0.5 mg/kg q12h. Reference ranges from cited sources — verify against current literature before clinical use.
Documented routes for Pyrimethamine in cats: PO.
Cited course lengths for Pyrimethamine in cats include: 14-28 days with trimethoprim-sulfa; taper to q24h after clinical improvement. Duration depends on the indication — match it to the specific dose rule in the table above.
Pyrimethamine is indicated in cats for: Toxoplasmosis.
These are general warnings for Pyrimethamine across species; consult the cat dosing table above for species-specific guidance. Bone marrow suppression possible — monitor CBC. Supplement with folinic acid (leucovorin). Teratogenic. Do not use in pregnant animals.
Why a species-specific page? Pyrimethamine pharmacokinetics differ across species: dose ranges, intervals, and route preferences are not interchangeable. Cross-extrapolation from canine doses is unsafe in cats — 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.