9 Hosseinpour Hosseinpour F F Ellfolk Ellfolk M M Norlin Norlin M M Wikvall Wikvall K K Phenobarbital suppresses vitamin D3 25-hydroxylase expression: a potential new mechanism for drug-induced osteomalacia Phenobarbital suppresses vitamin D3 25-hydroxylase expression: a potential new mechanism for drug-induced osteomalacia Biochem Biophys Res Commun. Here, CYP27A1 is linked to osteomalacia.