Clonidine in patients with diabetes and mild hypertension

Clonidine has been reported to adversely affect glucose tolerance in experimental animals and normal man. We assessed its short- and long-term effects in 10 patients with both mild hypertension and diabetes mellitus. Patients were studied before and 10 wk after treatment with 0.1 mg clonidine twice daily, which induced reductions in blood pressure (from 148 +/- 5/93 +/- 2 mm Hg sitting, to 125 +/- 4/80 +/- 2) and control of hypertension in all patients. Clonidine increased the glycemic response to intravenous glucose (incremental glucose AUC from 161 +/- 13 to 184 +/- 14) but did not significantly change long-term diabetic control as assessed by weekly fasting serum glucose, glycosylated hemoglobin, and 24-hr urinary glucose excretions before and after treatment. We conclude that low-dose clonidine controlled blood pressure and impaired the response to an acute glucose challenge in midly hypertensive, type II diabetic patients but did not adversely affect diabetic control over 10 wk.