The effect of age and cardiac failure on xamoterol pharmacokinetics.

1. Xamoterol is a cardioselective beta-adrenoceptor partial agonist which may have a role in the management of cardiac failure. Excretion is mainly by the renal route. 2. The kinetics of a single 200 mg oral dose of xamoterol were studied in eight elderly (age 67-82 years) volunteers, eight young (age 21-43 years) volunteers; eight patients with mild to moderate cardiac failure and eight age and sex matched controls. 3. Elderly volunteers had a significantly longer time to reach peak concentration (mean +/- s.e. mean 2.1 +/- 0.2 vs 1.1 +/- 0.1 h) and elimination half-life time (27.0 +/- 2.8 vs 16.4 +/- 3.1 h) compared with young volunteers. The renal clearance of xamoterol was lower in the elderly (115 +/- 12 vs 185 +/- 19 ml min-1) and showed a significant correlation with creatinine clearance (r = 0.85, P less than 0.001). 4. There was no significant difference in any of the pharmacokinetic parameters measured in patients with cardiac failure compared with healthy age and sex matched controls. 5. These results suggest that the maintenance dose of xamoterol could be reduced in elderly patients in relation to impairment of renal function.