Pharmacokinetics of carteolol in relation to renal function

The plasma levels and urinary excretion of carteolol and its main metabolites 8-hydroxycarteolol and carteolol glucuronide were investigated in 6 healthy subjects and 9 patients with varying degrees of renal impairment following a single oral dose of 30 mg carteolol hydrochloride. In healthy subjects the half-life of carteolol was 7.1 h. 63% of the administered dose was recovered unchanged in urine, and in all 84% was excreted by the kidneys. The renal clearance of carteolol was 255 ml/min. In chronic renal failure (CRF) the terminal half-life was increased to a maximum of 41 h. Both the elimination rate constant and renal clearance were closely related to the creatinine clearance. In CRF the recovery of carteolol and its metabolites from urine was considerably reduced, suggesting that another pathway of drug elimination becomes relevant in renal disease. To avoid an increase in side-effects due to drug accumulation, the dosage of carteolol should be adjusted in relation to the reduction in creatinine clearance. The maintenance dose should be reduced to a half in patients with a creatinine clearance below 40 ml/min and above 10 ml/min. In those with a creatinine clearance of 10 ml/min or less, the dose should be reduced to 1/4.