The bladder neck and prostate are rich in alpha receptors. It is believed that alpha blockade may reduce outflow obstruction, improve urinary flow, and even diminish intraprostatic ductal reflux. The clinical evidence examining the effects of alpha blockers in Category III patients, however, has been conflicting (see Table 2 below). Four small randomized trials examining the effects of alfuzosin, terazosin, tamsulosin, and doxazasin have confirmed a beneficial effect of alpha blockade in patients with recent onset of the disease and who have void co-symptoms and have not been heavily pretreated.20-23 Treatment must be continued for at least six weeks.
Conversely, two recent, large, NIH-sponsored, randomized trials did not confirm these findings. Alexander et al examined the effects of tamsulosin, ciprofloxacin, and combination therapy on heavily pretreated patients with chronic symptoms. Tamsulosin studied in heavily pretreated patients, with or without ciprofloxacin, was not shown to be effective compared with placebo,19 whereas alfuzosin evaluated in an alpha-blocker-naïve patient population diagnosed within two years failed to show any improvement in symptom reduction over placebo.24 A recent meta-analysis showed that alpha blockers do provide some amelioration of symptoms, but are not very effective monotherapies.25
These seemingly conflicting results highlight the difficulty of conducting studies on patients with heterogeneous symptoms. Within each group, the number of patients whose main bothersome symptoms were urinary in nature and who were likely to respond to alpha blockers was likely different. The suggestion, therefore, is to consider alpha blocker therapy in men with obstructive and/or irritative voiding symptoms.