PROGESTERONE - DOES IT AFFECT RESPONSE TO DRUG

This article presents an overview of the gamma-aminobutyric acid (GABA )-benzodiazepine receptor complex (GBRC) and its in vitro modulation b y THP, a metabolite of progesterone, as well as the results of a singl e-dose study of progesterone and triazolam in 16 post-menopausal women . The study results indicate that a 300 mg oral dose of progesterone a dministered 2.5 hours prior to a challenge dose of triazolam significa ntly increases sensitivity to triazolam: concentration values required for 50 percent of maximum effect (EC50) decreased by 20 to 32 percent after pre-treatment with progesterone. These data support the in vitr o findings that THP enhances binding of benzodiazepines to the GBRC. T he full clinical implications of these data, including extensions to o ther steroids, need to be explored.