Role of the sympathetic nervous system in hypertension and benign prostatic hyperplasia.

Hypertension and benign prostatic hyperplasia (BPH) have a number of features in common. For example, both occur with increasing frequency in the elderly, and both are a major source of health expenditure worldwide. However, the most striking feature linking hypertension and BPH is the aetiological role of the sympathetic nervous system. Sympathetic tone mediated by the alpha-receptor is vital in the control of blood pressure. By selectively inhibiting the alpha 1-adrenoceptors in the vasculature, thereby inhibiting the response to epinephrine and norepinephrine and thus reducing peripheral resistance, selective alpha 1-inhibitors such as doxazosin produce a physiological reduction in blood pressure. Receptors of the alpha 1 subtype are also found in the prostate, the urethra and bladder neck. Doxazosin, by reducing the tone of the prostatic smooth muscle, has the potential to improve urinary flow rate, as well as the obstructive and irritative symptoms characteristic of BPH.