Electrolyte changes and metabolic effects of lisinopril/bendrofluazide treatment. Results from a randomized,...

The metabolic effects of lisinopril and bendrofluazide therapy were studied in 61 patients with essential hypertension in a randomized, double-blind study with parallel groups. The insulin sensitivity index, measured by hyperinsulinemic euglycemic clamp test, decreased by 22% (P < .01) during bendrofluazide treatment and by 15% (NS) during lisinopril treatment. The initial insulin response at intravenous glucose tolerance test (IVGTT) increased by 21% (P < .05) during lisinopril treatment but decreased by 13% (P < .05) during treatment with bendrofluazide, and in addition, the glucose disappearance rate decreased by 9% (P < .05) in the latter group. During oral glucose tolerance test (OGTT), the area under the glucose curve (AUCglucose) increased by 17% (P = .05) in the bendrofluazide-treated group but decreased by 19% (P = .05) in the lisinopril group, although there was no difference between the drug effects on AUCinsulin. The LDL/HDL cholesterol ratio increased during bendrofluazide treatment. The serum potassium concentration decreased by 10% (P = .0001) during bendrofluazide treatment but increased by 6% (P = .0001) in the lisinopril-treated group. The change in serum potassium was correlated to the change in initial insulin response and glucose disappearance rate at IVGTT, and inversely correlated to the change in AUCglucose at OGTT. In conclusion, alterations in serum potassium balance may affect the initial insulin release and glucose disposal. Bendrofluazide treatment decreases the serum potassium concentration, reduces the initial insulin release and the glucose disposal, and, in addition, impairs insulin sensitivity. Lisinopril treatment increases serum potassium concentration and the initial insulin response, and decreases AUCglucose, but does not improve insulin sensitivity per se.