The effects of 1-year
antihypertensive treatment with the
diuretic fenquizone were evaluated in 16 patients with mild
essential hypertension. During treatment with placebo, after 2, 4, 24, and 52 weeks of treatment we measured blood pressure, heart rate, forearm blood flow (FBF) and vascular resistance (FVR) at rest and after 10 minutes
ischemia, and forearm venous distensibility. Subjects whose diastolic blood pressure after
fenquizone was reduced at least 10% were classified as responders. On this basis, 56% of patients after 1 month and 68% after 1 year responded to
fenquizone. Responders, in comparison to nonresponders, were characterized by a greater increase in FBF and a greater decrease in FVR. The reduction in diastolic blood pressure was significantly related to the fall in FVR whereas no correlation was found between blood pressure and venous compliance changes. Nonresponders had a PRA increase similar to that observed in responders but they showed a much greater increase in
aldosterone, whose changes were inversely related to modifications of both FVR and blood pressure. Our results demonstrate that chronic
therapy with
fenquizone causes a reduction of FVR, and that nonresponders have an exaggerated rise in
aldosterone. This observation further reinforces the hypothesis that factors influencing the secretion of
aldosterone are important determinants of the
antihypertensive mechanism of
diuretics.