A dose titration study evaluating terazosin, a selective, once-a-day alpha 1-blocker for the treatment of symptomatic benign prostatic hyperplasia.

The efficacy and safety of terazosin, a selective long-acting alpha-1-adrenergic blocker, were evaluated in 45 normotensive patients with symptomatic benign prostatic hyperplasia ranging from 50 to 76 years old. All patients underwent a complete urodynamic evaluation and transrectal prostatic ultrasonography before enrollment into the study. The dose of terazosin was titrated to 5 mg. per day for a 1-month interval, provided adverse drug reactions were not observed. Of the patients 39 (87%) completed the dose titration study. The parameters used to assess the effectiveness of terazosin included peak and mean urinary flow rates, micturition symptom scores and the global assessment by the patient of symptomatic improvement. Over-all, the mean systolic and diastolic blood pressures changed by less than 1%. The peak and mean urinary flow rates increased by 42 and 48%, respectively. The obstructive and irritative symptom scores improved by 63 and 35%, respectively. Over-all, 30 of the 45 participants (67%) indicated that the voiding symptoms were markedly improved while on terazosin. Five patients did not complete the dose titration study due to development of adverse drug reactions, including erectile dysfunction (7%), tiredness (7%), light-headedness (4%), palpitations (4%), nasal congestion (2%) and asymptomatic hypotension (2%). There were 25 patients (55%) followed on terazosin for 4 to 10 months (mean 6.5 months). The improvements in urinary flow rates and symptom scores were maintained for this interval. Although this preliminary experience with terazosin is encouraging, the ultimate role of terazosin for the long-term treatment of benign prostatic hyperplasia needs further evaluation.