Steady-state pharmacokinetic parameters of the new, long-acting beta-adrenoceptor blocker bopindolol have been measured in 17 young and 20 elderly healthy men. The t1/2-beta and the AUC(0 --> 24 h) of hydrolysed bopindolol (the active metabolite) were both increased (40% and 26%, respectively) in the elderly subjects but t(max), C(max) and CL/f were not altered. However, after adjusting the parameters to allow for the different average body weights of the two groups, C(max) and CL/f became significantly different (+29% and -30%, respectively). AUC(0 --> 24 h) was increased by 41%. The changes of up to 41% in pharmacokinetic parameters were smaller than the alterations of 50-100% usually seen when titrating doses of antihypertensive drugs. The clinical relevance of the effects was not examined, but similar changes have been reported for other beta-blockers which did not appear to be clinically relevant and did not affect the dosage required to treat hypertension.