Effect of coadministered salicylamide on terbutaline metabolism in rats.

Concomitant oral administration of salicylamide (200 mg/kg) and 3H-terbutaline (1 mg/kg) to rats with ligated bile ducts decreased absorption of terbutaline from the gut from 73 to 56% as measured by urinary excretion of radioactivity in 48 hr. No increase in the fraction of terbutaline excreted unchanged was observed, suggesting that salicylamide does not substantially inhibit the conjugation of terbutaline with glucuronic acid. An increase in the fraction of terbutaline excreted unchanged observed in normal animals may result from enhanced excretion of terbutaline glucuronide into bile rather than from inhibition of conjugation.