Metabolism of carvedilol in man

The metabolism of carvedilol was investigated in plasma and urine of 3 healthy male volunteers after administration of 50 mg of [14C]-labelled drug. Rapid and extensive biotransformation occurred. After 1.5 h 9% of total radioactivity in plasma consisted of unchanged drug, 22% of carvedilol-glucuronide and another 20% of oxidative cleavage products of the beta-blocking side chain. Urinary excretion of radioactivity amounted to 16% of which 2% represented unchanged drug, 32% carvedilol-glucuronide and about 25% side chain oxidation products. Ring-hydroxylated metabolites of carvedilol accounted for 18% of the radioactive compounds in the urine.