Kinetics of pamatolol, a cardioselective beta adrenoreceptor blocker

The systemic bioavailability, elimination half-life (t1/2), and plasma concentration--response relationships of pamatolol, a relatively cardioselective beta adrenoceptor blocker, have been measured in healthy subjects. Pamatolol is rapidly and completely absorbed after oral dosing. Elimination t1/2 ranged from 2.9 to 4.6 hr after oral doses and from 2.2 to 5.6 hr after intravenous doses. There was a clear relationship between log plasma pamatolol concentration and sympathetic blockade assessed by reduction of exercise heart rate. Concentration-response curves were essentially identical after oral and intravenous doses. There is no evidence of a first-pass effect, nor is there any evidence of metabolite activity.