ExoticRx · exoticrx.com/drugs/acetylcysteine-antidotal
US brand names:Mucomyst, Acetadote
Acetylcysteine (Antidotal) is dosed at 140 mg/kg IV Loading 140mg/kg IV, then 70mg/kg q6h x 5-7 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).. 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
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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 | Loading 140mg/kg IV, then 70mg/kg q6h x 5-7 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). |
| Dog (Domestic) | IV | 140 mg/kg | Loading 140mg/kg IV, then 70mg/kg q4h x 7 doses | Strong | 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.' |
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View PlansSource citations and evidence levels available on the live page. Reference only — verify against current literature before clinical use.