ExoticRx · exoticrx.com/drugs/acetylcysteine-antidotal
US brand names:Mucomyst, Acetadote
Acetylcysteine (Antidotal) is dosed at 140 mg/kg IV Load 140 mg/kg IV, then 70 mg/kg q6h, min 7 doses in cats, per Avizeh R, Najafzadeh H, Razijalali M, Shirali S. Evaluation of prophylactic and therapeutic effects of silymarin and N-acetylcysteine in acetaminophen-induced hepatotoxicity in cats. J Vet Pharmacol Ther. 2010;33(1):95-99. doi:10.1111/j.1365-2885.2009.01100.x — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.40 (2026-08-01). — Plumb's 10th ed (held) printed p.13, Acetylcysteine monograph spanning p.12-13; page located 2026-08-05 from the book's own running heads, and carries this exact dose under the matching species heading. — SOURCE EDITION: Plumb's Veterinary Drug Handbook — ISBN 9781394172207, https://openlibrary.org/isbn/9781394172207. Verify against current literature before clinical use.
Provides cysteine for hepatic glutathione regeneration, conjugating the toxic NAPQI metabolite of acetaminophen. Also acts as direct free radical scavenger.
IV preferred for severe toxicosis. PO causes vomiting due to taste/smell. Loading dose followed by maintenance. Most effective within 8-10 hours of ingestion.
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 |
|---|---|---|---|---|---|
| Cat (Domestic) | IV | 140 mg/kg | Load 140 mg/kg IV, then 70 mg/kg q6h, min 7 doses | Strong | Avizeh R, Najafzadeh H, Razijalali M, Shirali S. Evaluation of prophylactic and therapeutic effects of silymarin and N-acetylcysteine in acetaminophen-induced hepatotoxicity in cats. J Vet Pharmacol Ther. 2010;33(1):95-99. doi:10.1111/j.1365-2885.2009.01100.x — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.40 (2026-08-01). — Plumb's 10th ed (held) printed p.13, Acetylcysteine monograph spanning p.12-13; page located 2026-08-05 from the book's own running heads, and carries this exact dose under the matching species heading. — SOURCE EDITION: Plumb's Veterinary Drug Handbook — ISBN 9781394172207, https://openlibrary.org/isbn/9781394172207 |
| Dog (Domestic) | IV | 140 mg/kg | Load 140 mg/kg then 70 mg/kg q4h IV or PO x5 doses |
Upgrade to Pro or Student to unlock the full dose ranges and frequency for every species. The drug's mechanism, warnings, indications, and cited sources are free to read.
View PlansSource citations and evidence levels available on the live page. Reference only — verify against current literature before clinical use.
| Papich, Saunders Handbook of Veterinary Drugs, 4th ed. (2016), Acetylcysteine monograph, printed p. 8 (corpus papich p. 36), Small Animal Dosage / Dogs and Cats: 'Antidote: 140 mg/kg (loading dose), then 70 mg/kg q4h IV or PO for 5 doses.' — SOURCE EDITION: Saunders Handbook of Veterinary Drugs — ISBN 9780323244855, https://openlibrary.org/isbn/9780323244855 |