Glucose metabolism during long-term treatment with prazosin.

The metabolic effects of the alpha 1-adrenoceptor blocking drug prazosin was evaluated in 8 premenopausal women undergoing treatment for essential hypertension. Intravenous glucose tolerance (IVGTT) and the early insulin response was studied before treatment, after 1 and 12 months and 3 weeks after cessation of drug treatment. The k-value for the glucose disappearance decreased from 2.9 to 2.0 after 1 month. No further change occurred after 12 months. After cessation of the drug the k-value returned to the pre-treatment level. The decreased glucose tolerance was accompanied by a decrease in the early insulin response. It is suggested that the reversible decrease in glucose tolerance is due to an inhibition of the early insulin response, mediated by the increase in circulating catecholamines reported during prazosin treatment.