Hypothyroidism in diabetes treated with the sulphonylurea chlorpropamide - abstract

ABSTRACT

The study was undertaken to determine the effects of the sulphonylurea, chlorpropamide (Diabin) on thyroid function in diabetics. One hundred and twenty-five diabetic attending the Diabetic Clinic at the University of the West Indies were studied. They were divided into three groups, a control group of 46 patients on diet alone (11) or insulin (35), a second group of 46 patients on 250 mg chlorpropamide daily and a third group of 33 patients receiving 375 mg or more chlorpropamide daily. The three groups were matched for age, sex and duration of diabetes. No patient had been on other drugs known to affect thyroid function and they all had blood urea values within normal limits. A serum thyroxine estimation was done on each subject and all those values of less than 4.5 ug/100 ml were subjected to R.A.I. uptake studies before and after a single dose of T.S.H. In the control group 1 patient was found to have Hashimoto's disease. In each of the other two groups on chlorpropamide there were 3 hypothyroid patients. They all had low serum T4, low R.A.I. uptakes and good response to T.S.H. In three of these six patients the sulphonyl-urea was discontinued and the thyroxine levels rose to normal after varying intervals. It is concluded from this series that hypothyroidism occurs in 7.5 percent of patients on chlorpropamide and that this reversible on discontinuation of the drug (AU)