The mechanism of adverse events associated with terazosin: an analysis of the Veterans Affairs cooperative study.

PURPOSE

We determined the mechanism of adverse events associated with alpha1-blockers for treating benign prostatic hyperplasia (BPH).

MATERIALS AND METHODS

We randomized 1,229 men with clinical BPH at 31 Veterans Affairs medical centers into equal treatment groups, including those who received placebo, terazosin, finasteride, and combined terazosin and finasteride therapy, respectively. Adverse events were captured at all study visits during our 1-year study. Our current review of adverse events is limited to patients randomized to the placebo and terazosin groups. We compared the incidence of orthostatic blood pressure change, postural symptoms and orthostatic hypotension in men who were normotensive and hypertensive at baseline, respectively. We also determined the association of changes in systolic blood pressure with the incidence of treatment related adverse events.

RESULTS

The treatment related rates of dizziness, asthenia, postural hypotension and syncope were 19%, 6%, 6% and 1%, respectively. Of these adverse events only postural hypotension was associated with orthostatic blood pressure changes. The incidence of asthenia, dizziness and postural hypotension was not significantly greater in patients with a systolic blood pressure decrease of 5 or greater and less than 5 mm. Hg, respectively.

CONCLUSIONS

Dizziness and asthenia are not associated with changes in blood pressure, suggesting that these treatment related adverse events associated with alpha1-blockers are not related to vascular events. Designing a subtype selective alpha1 antagonist that has less effect on blood pressure may not result in marked improvement in tolerability over commercially available alpha1-blockers.