Lipoic acid is 10 times more toxic in cats than reported in humans, dogs or rats


Author's address: Dr Ana Hill, College of Veterinary Medicine, 601 Vernon L. Tharp St, The Ohio State University, Columbus, OH 43210, USA, E-mail:


The antioxidant lipoic acid (LA) is administered to humans and pets. We described acute toxicity and maximum tolerated dose (MTD) of LA in cats. In progression, 10 healthy adult male cats received orally 60 (high), 30 (low), or 0 mg LA/kg (control). Serum enzyme activities and concentrations of bile acids, ammonia, amino acids (AA), LA and dihydrolipoic acid (DHLA) were measured, and tissues examined microscopically. Significant clinical toxicity with changes in ammonia and AA concentrations occurred in all high-dose cats. Oral LA produced hepatocellular toxicity and MTD was <30 mg/kg in cats.