Determinants of hypotensive response to thiazide diuretic

Sequential changes in vascular resistance in nonresponders (blue squares) and responders (red circles) to the hypotensive effect of a thiazide diuretic in patients with primary hypertension (formerly called "essential" hypertension). Although both groups had an initial diuresis and reduction in plasma volume, there was no significant fall in blood pressure in the nonresponders due to a rise in vascular resistance mediated in part by increased production of angiotensin II. In comparison, vascular resistance fell over time in the responders via an unknown mechanism.