From Dog

N-acetylcysteine is an antioxidant nutritional supplement used primarily for hepatitis[1], cholangiohepatitis and acetaminophen toxicity in dogs.

This drug provides a source of cysteine for glutathione synthesis. This increases antioxidant protection from the toxic effects of NAPQI and thus decreases methemoglobin formation. It also provides sulfate that can be utilized for conjugation, supporting metabolism of acetaminophen to a nontoxic compound. NAC may also have an antioxidant effect by directly reducing free radicals.

This drug is recommended for any hospitalized patient, regardless of disease, where there is depletion of antioxidants. Supplementing dogs with N-acetylcysteine during the first 48 hours of hospitalization has been shown to significantly increase cysteine, normalize glutathione concentrations, and decrease the degree of lipid peroxidation associated with illness[2].

Recommended dose in dogs is 60 - 70 mg/kg twice daily, usually given as a constant rate intravenous infusion[3].


  1. Webster CR & Cooper J (2009) Therapeutic use of cytoprotective agents in canine and feline hepatobiliary disease. Vet Clin North Am Small Anim Pract 39(3):631-652
  2. Viviano KR & Vanderwielen B (2013) Effect of N-Acetylcysteine Supplementation on Intracellular Glutathione, Urine Isoprostanes, Clinical Score, and Survival in Hospitalized Ill Dogs. J Vet Intern Med Mar 4
  3. Alipour M et al (2013) Safety and pharmacokinetic studies of liposomal antioxidant formulations containing N-acetylcysteine, α-tocopherol or γ-tocopherol in beagle dogs. Toxicol Mech Methods Feb 6