The effect of chlorothiazide on bone-related biochemical variables in normal post-menopausal women.

OBJECTIVE

To evaluate the effects of short-term administration of chlorothiazide on fasting urinary hydroxyproline, an index of bone resorption, and other bone-related biochemical parameters in normal post-menopausal women.

DESIGN

Subjects served as their own control before and after chlorothiazide treatment.

SETTING

Subjects were recruited by advertisement.

PARTICIPANTS

Thirteen healthy post-menopausal women with a mean age of 65 years.

INTERVENTION

Each subject was given chlorothiazide 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

Chlorothiazide 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.

CONCLUSION

Chlorothiazide decreases fasting urinary hydroxyproline, a marker of bone resorption in post-menopausal women. This observation supports a potential role for thiazide diuretics in the prevention of osteoporosis. The observed fall in urinary hydroxyproline is of the same order as that seen after treatment with estrogen or calcium supplements.