CLINICAL EXPERIENCE WITH ACTINOMYCIN C

Problems in Predicting Drug Effects across Species Lines

During the course of drug development, there are many instances where extrapolation of data from animals to man is difficult because the toxicologic and metabolic responses induced by drugs may be significantly different between the laboratory species. In cases where the drug in question has a potentially major therapeutic use in man, it is suggested that the data be evaluated on the basis of a pragmatic benefit-to-risk ratio, rather than zero-toxicity. In this way, we may provide drug therapy for those patients for whom adequate treatment does not exist, as well as protect those individuals who may be exposed to some hazard from the use of medicines.

Absorption of the beta-adrenergic-blocking agent, nadolol, by mice, rats, hamsters, rabbits, dogs, monkeys, and man: an unusual species difference

1. Dogs absorbed [14C]nadolol almost completely (88--104%) after oral administration of 10--75 mg/kg. In contrast, mice, rats, hamsters, and rabbits, given oral doses of 20 mg/kg, absorbed, at most, 25%. After administration of oral doses of 2--75 mg/kg, monkeys absorbed no more than an average of 30%. Six monkeys given oral doses of 10 mg/kg absorbed 12--44%. 2. In rats, [14C]nadolol was orally absorbed to an average of 13.7--17.5%, whether given in suspension or in solution, indicating that absorption was not limited by rate of dissolution nor by solubility. 3. Mildly hypertensive humans given single doses of [14C]nadolol (2 or 80 mg, orally) and normal subjects given single doses (10 mg, orally) absorbed an average of 20.4--33.3%.