DOXAZOSIN IMPROVES INSULIN SENSITIVITY IN HYPERTENSIVE PATIENTS

Insulin sensitivity in terms of glucose disposal rate was measured by the hyperinsulinemic/euglycemic clamp technique in 10 hypertensive pat ients and 7 normotensive control subjects before and after 12 weeks of doxazosin therapy. Supine blood pressure fell significantly, from 150 /98 mmHg before treatment to 136/90 mmHg after treatment (systolic P<0 .001/diastolic P<0.01). The average dose of doxazosin at the end of th e study was 3.3 +/- 0.4 mg/day. The glucose disposal rate during the l ast 30 minutes of the glucose clamp procedure was significantly increa sed, from 5.8 +/- 0.7 mg/kg/min before to 7.8 +/- 0.7 mg/kg/min after treatment (P<0.02). Insulin sensitivity was 8.7 +/- 0.4 mg/kg/min in t he normotensive subjects, which represented a significant difference w hen compared with that of the hypertensive subjects before treatment ( P<0.01). Steady-state serum insulin concentrations, as measured during the glucose clamp procedure, were 172 +/- 10.4 muU/ml before and 176 +/- 13.5 muU/ml after doxazosin treatment; these levels were significa ntly higher than the 137 +/- 7.0 muU/ml reading obtained in the normot ensive subjects (P<0.05). Study results show that hypertensive patient s tend to be insulin resistant and that treatment with doxazosin impro ves insulin sensitivity.