Pharmacokinetics of unlabelled and14C-labelled pindolol in uraemia

Summary The elimination of pindolol in 25 patients with various degrees of renal failure has been studied after an intravenous dose of 3 mg. A linear correlation was not found between the elimination rate of pindolol and the endogenous creatinine clearance, and the half-life of the unchanged drug was independent of the severity of the renal failure. This implies greater metabolism of pindolol in anuric patients and the extrarenal elimination rate constantk_mwas increased. Three patients with severe renal failure were given 3 mg¹⁴C-pindolol. They showed almost constant plasma levels of radio-activity for 6 h and then slow excretion with a half-life of 48 h, because of accumulation of metabolites in the blood. Up to 90% of the metabolites are glucuronides and sulphates which have no beta-blocking or other clinical activity. Thus, to produce beta-adrenergic blockade the same dose of indolol is required in healthy patients as in those with uraemia.