A randomized double-blind study assessing 4 versus 8 mg. doxazosin for benign prostatic hyperplasia.

Purpose: We compare the efficacy of 4 versus 8 mg. doxazosin for benign prostatic hyperplasia.

Materials And Methods: A total of 82 patients with benign prostatic hyperplasia successfully treated with 4 mg. doxazosin were randomized in a double-blind fashion to take 4 or 8 mg. Patients were evaluated with American Urological Association (AUA) symptom score, Boyarsky score, uroflowmetry and side effect profile before, and 1 and 3 months following randomization.

Results: Of the patients 42 and 40 were randomized to receive 4 and 8 mg. doxazosin, respectively. Both groups were similar with respect to patient age, baseline Boyarsky and AUA symptom scores, and baseline maximum urinary flow rate. At 3 months mean improvement from baseline plus or minus standard deviation in Boyarsky score was 0.6 +/- 6.5 and 4.9 +/- 6.6 in the 4 and 8 mg. groups (p <0.05), respectively, mean improvement in AUA symptom score was 1.6 +/- 5.3 and 5.3 +/- 8.0 (p <0.05), and mean maximum flow rate difference was -0.6 +/- 6.4 and +1.4 +/- 7.9 (p >0.05). Of the patients 7 and 8 in the 4 and 8 mg. groups dropped out of the study, and there were no statistical differences in side effects between dosages.

Conclusions: A dose of 8 mg. doxazosin was more efficacious than 4 mg. and the side effects associated with both dosages appeared to be similar. The 8 mg. dose should be tried in patients who have not achieved an adequate therapeutic response to 4 mg. and are tolerating the medication. Consideration should be given to increasing the dosage to 8 mg. in patients who are clinically improved at lower dosages.