Dog · Canis lupus familiaris · typical adult weight 2.00–80.00 kg
Pyrimethamine is dosed at 0.25–1 mg/kg PO q24h; 0.25-0.5 mg/kg may be given q12h in dogs, per Plumb's Veterinary Drug Handbook, 10th ed., printed p.1100 (corpus PDF p.1127), Dosages > DOGS; corroborated by BSAVA Small Animal Formulary 10th ed., Pyrimethamine, printed p.354 (corpus PDF p.370) - 'Dogs, Cats: Toxoplasmosis/neosporosis: 1 mg/kg p.o. q24h or divided q12h for 4 weeks, alongside sulphonamides' — SOURCE EDITION: BSAVA Small Animal Formulary, Part A — Canine and Feline — ISBN 9781910443705, https://openlibrary.org/isbn/9781910443705; Plumb's Veterinary Drug Handbook — ISBN 9781394172207, https://openlibrary.org/isbn/9781394172207. Pyrimethamine is used in dogs for Toxoplasmosis/Neosporosis. Routes documented in dogs: PO. A typical adult dog weighs 2.00–80.00 kg. ExoticRx lists 1 cited dose rule for Pyrimethamine in dogs, drawn from published veterinary references. Verify against current literature before clinical use.
US trade names: Daraprim
| Route | Dose | Frequency | Duration | Indication | Evidence | Source |
|---|---|---|---|---|---|---|
| PO | 0.25–1 mg/kg | q24h; 0.25-0.5 mg/kg may be given q12h | 14-28 days; combine with sulfonamide; supplement folinic acid | Toxoplasmosis/Neosporosis | Weak | Plumb's Veterinary Drug Handbook, 10th ed., printed p.1100 (corpus PDF p.1127), Dosages > DOGS; corroborated by BSAVA Small Animal Formulary 10th ed., Pyrimethamine, printed p.354 (corpus PDF p.370) - 'Dogs, Cats: Toxoplasmosis/neosporosis: 1 mg/kg p.o. q24h or divided q12h for 4 weeks, alongside sulphonamides' — SOURCE EDITION: BSAVA Small Animal Formulary, Part A — Canine and Feline — ISBN 9781910443705, https://openlibrary.org/isbn/9781910443705; Plumb's Veterinary Drug Handbook — ISBN 9781394172207, https://openlibrary.org/isbn/9781394172207 |
Every held source for this drug and species, as printed. Where they differ, both are shown — the choice is yours, not ours.
The sources disagree for this combination. The ranges below do not overlap on a comparable route. This is not an error in one of them — published veterinary references differ, and reconciling them for a particular patient is a clinical judgement.
| Dose (mg/kg) | Route | Source | As printed |
|---|---|---|---|
| 1 | PO | BSAVA Small Animal Formulary, 10th ed — Part A (Canine and Feline)p.370 | Toxoplasmosis/neosporosis: 1 mg/kg p.o. q24h or divided q12h for 4 weeks, alongside sulphonamides. |
| 1 | PO | Papich Saunders Handbook of Veterinary Drugs, 4th edp.726 | • 1 mg/kg pyrimethamine and 20 mg/kg sulfadiazine once daily PO. (Equivalent |
| 20 | PO | Papich Saunders Handbook of Veterinary Drugs, 4th edp.726 | • 1 mg/kg pyrimethamine and 20 mg/kg sulfadiazine once daily PO. (Equivalent |
Figures are transcribed from the cited page or table of each held edition and are shown for reference only. They are not dose recommendations, they do not feed the calculator, and none has been reviewed by a veterinarian.
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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 dogs may differ from canine / feline reference data — consult the primary citations listed with each rule.
Pyrimethamine dose range in dogs, with cited source references: PO 0.25–1 mg/kg q24h; 0.25-0.5 mg/kg may be given q12h. Reference ranges from cited sources — verify against current literature before clinical use.
Documented routes for Pyrimethamine in dogs: PO.
Cited course lengths for Pyrimethamine in dogs include: 14-28 days; combine with sulfonamide; supplement folinic acid. Duration depends on the indication — match it to the specific dose rule in the table above.
Pyrimethamine is indicated in dogs for: Toxoplasmosis/Neosporosis.
These are general warnings for Pyrimethamine across species; consult the dog 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 dogs — 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.