Toxicity studies on noscapine

Abstract

Noscapine dissolved in dilute HCl had an LD 50 of 83 mg/kg i.v. in mice. Acute toxicity by the subcutaneous route could not be determined, apparently owing to lack of absorption. The orally administered drug produced death in rats only in doses exceeding 800 mg/kg. Since the oral antitussive dose, both in animals and in man, is on the order of 1 mg/kg, a large margin of safety is indicated. Chronic oral administration to dogs of 30 mg/kg 5 days per week for 13 weeks yielded no signs of toxicity. Very high doses in rats, 0.2% or 0.5% in the diet, produced moderately enlarged livers, with slight increase in liver lipid. This finding was absent at a drug level of 0.05% in the diet, where the estimated drug intake was still far beyond the therapeutic dose.