Toxicity and Pharmacology of Piracetam

Toxicity and Pharmacology of Piracetam

One of piracetam¡¯s most unique and conspicuous features is its extremely low toxicity. The classical measure of drug toxicity, the LD-50 (the dose causing death for 50% of test animals), is not applicable; standard dosing methods (oral, intravenous injection, intraperitoneal injection) cannot deliver enough piracetam to kill laboratory animals. Doses of greater than 20 g/day have been given to people suffering from myoclonic seizure disorders, without serious side effects [Karacostas et al., 1993]. The recommended dose of piracetam for infants with myoclonic seizures is 10-20 g/day (approximately 1-2 rounded tablespoons), a phenomenally high dose by normal drug standards.

Piracetam is absorbed rapidly and completely following oral intake, and it is excreted predominantly unchanged in the urine. Peak plasma levels are reached in less than an hour. However, brain concentrations rise more slowly. It may take days for piracetam to reach peak levels in the brain, and days for it to fall after discontinuation.