A three month double-blind study of doxazosin as treatment for benign prostatic bladder outlet obstruction



Objective To evaluate the efficacy and tolerability of doxazosin in the treatment of bladder outflow obstruction resulting from benign prostatic hyperplasia (BPH).

Patients and methods One-hundred and thrity-five patients with symptomatic urodynamicaly confirmed obstructive BPH ware treated for 12 weeks with either doxazosin (67 patients) or placebo (68 patients) after an initial 2 week baseline evaluation. The main outcome measures were urodynamic and symptomatic evaluation for efficacy. Blook pressre and adverse events were monitored.

Results Date were obtained in 122 patients (60 doxazosin, 62 placebo). Doxazosin produced increases in both mean and maximum urinary flow rates of 1.01 ml/s and 3.2 ml/s rspectively, compared with 0.21 ml/s and 2.2 ml/s on placebo. The increase in mean flow rate was statistically significant (P=0.04). While that for maximun flow rate approached significance (P= 0.09). The maximum subracted voiding pressure was substantially reduced (P=0.007) and 19 of 53 (36%) patients had an increase in maximum flow rate of 50% or more compared with 9 of 54 (17%) on placebo (P=0.024). Twelve weeks' therapy with doxaosin resulted in significant improvements (compared with placebo) in: hesitancy 9doxazosin 26 of 46. placebo 11 of 43; P=0.003), impaired urinary stream (doxazosin 31 of 55, placebo 16 of 48; P=0.019). nocturia (doxazoshin 22 of 56, placebo 10 of 54; P=0.017) and urgency (doxazosin 27 of 45, placebo 16 of 42; P=0.041). Frequency improved with doxazosin therapy (doxazosin 26 of 59, placebo 15 of 55; P=0.062). Adverse events, most frequenly dizziness and headache, were usually mild and transient and led to a discontinuation of doxazosin therapy in one patient. No clinically significant changes in sexual function or blood pressure were seen.

Conclusion Doxazosin was well-tolerated and produced both urodynamic and symptomatic improvement in men with BPH. thereby providing a satisfactory alterntive to existing drugs with the additional benefit of one dily dosage.