Pindolol: A Pharmacokinetic Comparison with other Beta‐Adrenoceptor Blocking Agents

The pharmacokinetic properties of the nine most frequently studied β‐adrenoceptor blocking agents (alprenolol, atenolol, metoprolol, oxprenolol, pindolol, practolol, propranolol, sotalol and timolol) were compared. Some pharmacokinetic parameters were found to be quite similar or at least not relevantly different in this group of drugs: e.g. the rate and the amount of absorption, the distribution volume, the elimination half‐life, the total clearance and the total urinary excretion. However, some other pharmacokinetic parameters: e.g. the daily dosage, the oral bioavailability, the first‐pass effect and the ratio of renal versus hepatic clearance, were surprisingly different in this series of drugs. A good correlation between systemic availability and urinary excretion of unchanged drug could be demonstrated for the beta‐adrenoceptor blocking agents. The pharmacokinetic comparison in this series of beta‐blockers revealed that pindolol has some relevant advantages. Due to the moderate metabolism, a negligible first‐pass effect results which yields a high oral bioavailability and leads to small interindividual variations in plasma levels and effects. As a result of the balanced clearance by the liver and the kidney and probably some compensating factors, no accumulation of pindolol has to be expected in patients with partial liver or kidney impairment. Therefore, apart from possessing the lowest daily dosage of the studied beta‐blockers, pindolol administration is relatively less likely to be critical in patients with partial renal or hepatic insufficiency.