Effect of the α₁-blocker doxazosin on diabetic nephropathy - Comparison with α,b-blockers

Despite the favorable effect of α₁-blockers on serum lipids and glucose tolerance, they have not been widely used in patients with diabetic nephropathy due to the risk of orthostatic hypotension. However, doxazosin causes a lower incidence of orthostatic hypotension than the representative α₁-blocker prazosin. Therefore its effects on diabetic nephropathy and blood pressure were compared with those of the α,β-blocker amosulalol hydrochloride in 23 and 24 patients with non-insulin-dependent diabetes, respectively. Both drugs produced a decrease in blood pressure, and doxazosin significantly lowered microalbuminuria from 95±128 mg/day to 66±120 mg/day (p<0.05), without decreasing creatinine clearance. This effect on microalbuminuria was independent of the degree of blood pressure reduction. Doxazosin had a favorable effect on serum lipids and glucose tolerance. Amosulalol hydrochloride also had a favorable effect on lipids, but produced no changes in glucose metabolism. Both doxazosin and amosulalol hydrochloride were concluded to be useful as antihypertensive agents for administration to patients with diabetes. Doxazosin significantly reduced microalbuminuria without impairing renal function, and could therefore be a useful therapy for patients with diabetes.