Effect of Doxazosin on Arterial Elasticity: Functional versus Structural Changes

Drugs and diseases have differential effects on functional and structural components of large‐conduit arteries and smaller vessels. The objective of this study was to demonstrate functional and structural effects of doxazosin (DOX) on large‐ vessel and small‐vessel arterial elasticity in hypertension (HTN). This was an open‐label, single‐blind, active‐therapy study. Patients with stage 1to 2 HTN were administered DOX 2 mg/day for 3 months and 4 mg/day for 1 month, if indicated, followed by 2‐week washout period. Arterial elasticity was measured noninvasively at baseline, at 3 months and 4 months of treatment, and 2 weeks following DOX withdrawal. Although the observed effects were not statistically significant, large‐vessel elasticity (C1) increased in a dose‐related manner and returned to baseline 2 weeks after drug withdrawal. There was a trend toward an increase in small‐vessel elasticity in a dose‐related manner. However, 2 weeks after drug withdrawal, C2 (distal elasticity) had not returned to baseline and was statistically significantly different from baseline (p = 0.032). It was concluded that large‐artery compliance increased in a dose‐related manner. Almost all benefit was lost within 2 weeks of discontinuation, suggesting the DOX effect was functional. Small‐artery compliance improved in a dose‐related manner but only partially returned to baseline after DOX withdrawal, suggesting changes in artery structure by DOX.