Loss of therapeutic control in congenital adrenal hyperplasia due to interaction between dexamethasone and primidone.
A 14-year-old girl with congenital adrenal hyperplasia showed rapid conversion from undertreatment to overtreatment when primidone, used to treat coexistent epilepsy, was withdrawn while on a constant steroid dose. In addition to signs of hypercortisolism and a decrease in random measurements of plasma testosterone and 170H-progesterone concentrations, the deterioration in control was also illustrated by changes in the pattern of blood spot steroid profiles. Adequate control was achieved only after a 3-fold reduction in steroid dose. The decrease in dose requirement was probably the result of a reversal of liver enzyme induction consequent upon the withdrawal of primidone.
Young
M C
MC
Department of Child Health, University of Wales College of Medicine, Cardiff, UK.
Hughes
I A
IA
D000293:Adolescent; D000312:Adrenal Hyperplasia, Congenital / Q000150:complications / Q000188:drug therapy*; D003907:Dexamethasone / Q000037:antagonists & inhibitors / Q000493:pharmacokinetics / Q000627:therapeutic use*; D004347:Drug Interactions; D004827:Epilepsy / Q000188:drug therapy; D005260:Female; D006801:Humans; D011324:Primidone / Q000494:pharmacology* / Q000627:therapeutic use; D011374:Progesterone / Q000097:blood; D013739:Testosterone / Q000097:blood
D011324:Primidone; D013739:Testosterone; D011374:Progesterone; D003907:Dexamethasone