[Bilrubinemia after administration of nicotinic acid (author's transl)]

Nicotinic acid concentrations in the serum over 80 mug/100 ml induce at the start of high dosage nicotinic acid therapy an acute rise in bilirubin to 1-3mg/100 ml serum. Even after postprandial administration there are clearly raised bilirubin concentrations in the serum. After treatment for 1 week with 0.5 g nicotinic acid daily by mouth the bilirubin increase is no longer detectable. The increased bilirubin concentrations in the serum are apparently the result of a transient inhibition of glucuronyl-transferase and is not a symptom of an acute liver disorder. When starting high dosage nicotinic acid therapy, therefore, disorders of the bilirubin metabolism and liver function must be excluded by differential diagnosis in doubtful cases. Further investigations are necessary to see whether the high concentrations of nicotinic acid in the serum cause competition with other drugs for the bilirubin-specific glucuronyl-transferase.