Rechallenge with crystalline niacin after drug-induced hepatitis from sustained-release niacin.

Niacin (nicotinic acid) is available in several forms, including crystalline preparations and various types of sustained-release preparations. Evidence exists that sustained-release niacin, with respect to both dosage and severity, is more hepatotoxic than crystalline niacin. Three patients who developed hepatitis during treatment with sustained-release niacin were rechallenged with equivalent or higher doses of crystalline niacin, with no evidence of recurring hepatocellular damage. Although the mechanism for niacin-induced hepatitis is unknown, these cases support previous observations that crystalline niacin may be less hepatotoxic than sustained-release preparations in certain patients.