title: Duration of action and plasma levels of beta-adrenoceptor blocking drugs.
abstract: Since beta-adrenoceptor blocking drugs exhibit a long duration of action "despite" an elimination half-life of usually between 2 and 6 hours, it has been postulated that no direct correlation could exist between the time course of plasma levels and that of pharmacodynamic effects. Results of a study are reported in which 20 mg pindolol were administered orally to 8 healthy volunteers. Exercise tests were carried out and pindolol levels determined at various times for up to 24 hours after drug administration. A linear fall of the pharmacological effect (reduction of exercise-induced tachycardia) and an exponential fall of pindolol plasma levels were observed, indicating a linear relationship between the reduction of exercise-induced tachycardia and the logarithm of plasma concentration.
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000097:blood / Q000494:pharmacology*; D000328:Adult; D005080:Exercise Test; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D013997:Time Factors
chemical_list: D000319:Adrenergic beta-Antagonists