ExoticRx · exoticrx.com/drugs/leflunomide
US brand names:Arava
Leflunomide is dosed at 2–4 mg/kg PO q24h in dogs, per Swann JW, Garden OA, Fellman CL, et al. ACVIM consensus statement on the treatment of immune-mediated hemolytic anemia in dogs. Journal of Veterinary Internal Medicine. 2019;33(3):1141-1172. doi:10.1111/jvim.15463; Colopy SA, Baker TA, Muir P. Efficacy of leflunomide for treatment of immune-mediated polyarthritis in dogs: 14 cases (2006-2008). Javma-Journal of the American Veterinary Medical Association. 2010;236(3):312-318. doi:10.2460/javma.236.3.312 — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.766 (2026-08-01).. Verify against current literature before clinical use.
Inhibits dihydroorotate dehydrogenase blocking de novo pyrimidine synthesis in rapidly dividing lymphocytes. Immunomodulatory.
Used for immune-mediated polyarthritis and other immune-mediated diseases. Hepatotoxic — monitor liver enzymes. Teratogenic. Diarrhea, anorexia. Slow onset (weeks).
Species references:All Cat (Domestic) drugsAll Dog (Domestic) drugs
Each ExoticRx dose rule is graded by the strength of its primary evidence — see the editorial process.
A dog/cat sample is shown here. Cited dosing for all 2 species — reptiles, birds, pocket pets, livestock, and equine — is free on the per-species pages above. Pro adds the weight-based calculator for every species.
| Species | Route | Dose | Frequency | Evidence | Source |
|---|---|---|---|---|---|
| Dog (Domestic) | PO | 2–4 mg/kg | q24h | Moderate | Swann JW, Garden OA, Fellman CL, et al. ACVIM consensus statement on the treatment of immune-mediated hemolytic anemia in dogs. Journal of Veterinary Internal Medicine. 2019;33(3):1141-1172. doi:10.1111/jvim.15463; Colopy SA, Baker TA, Muir P. Efficacy of leflunomide for treatment of immune-mediated polyarthritis in dogs: 14 cases (2006-2008). Javma-Journal of the American Veterinary Medical Association. 2010;236(3):312-318. doi:10.2460/javma.236.3.312 — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.766 (2026-08-01). |
| Cat (Domestic) | PO | 2–4 mg/kg | q24h | Weak |
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View PlansSource citations and evidence levels available on the live page. Reference only — verify against current literature before clinical use.