Glutethimide and circulating 1,25-dihydroxyvitamin D in vitamin D intoxication.

Iqbal and Taylor used glutethimide to treat a patient with vitamin D2 intoxication, reasoning that induction of hepatic microsomal enzymes by the drug would result in more rapid catabolism of vitamin D metabolites. The treatment corrected the hypercalcaemia, and the raised serum total 25-hydroxyvitamin D concentration fell with induction of the enzymes, as indicated by a rise in y-glutamyltransferase activity, but rose again when induction was stopped. Lukaszkiewicz et al successfully treated vitamin D3 intoxication in a 7 month old boy using phenobarbitone and phenytoin to induce hepatic microsomal enzymes.2 We report further analyses of the vitamin D metabolites in Iqbal and Taylor's patient.