THE EFFECT OF CHLOROTHIAZIDE ON BONE-RELATED BIOCHEMICAL VARIABLES INNORMAL POSTMENOPAUSAL WOMEN

Objective: To evaluate the effects of short-term administration of chl orothiazide on fasting urinary hydroxyproline, an index of bone resorp tion, and other bone-related biochemical parameters in normal post-men opausal women. Design: Subjects served as their own control before and after chlorothiazide treatment. Setting: Subjects were recruited by a dvertisement. Participants: Thirteen healthy post-menopausal women wit h a mean age of 65 years. Intervention: Each subject was given chlorot hiazide 500 mg bd po for 7 days. Fasting blood and urine samples were obtained immediately before the commencement of chlorothiazide (day 1) and 2 and 7 days after starting chlorothiazide. Results: Chlorothiazi de decreased the urinary calcium/creatinine (mean value day 1, 0.267; day 2, 0.143; day 7, 0.135; P < 0.001) and hydroxyproline/creatinine ( day 1, 0.0192; day 2, 0.0145; day 7, 0.0139; P < 0.02) molar ratios. C onclusion: Chlorothiazide decreases fasting urinary hydroxyproline, a marker of bone resorption in post-menopausal women. This observation s upports a potential role for thiazide diuretics in the prevention of o steoporosis. The observed fall in urinary hydroxyproline is of the sam e order as that seen after treatment with estrogen or calcium suppleme nts.