Abstract :
HTN and BPH occur frequently throughout the world. Over 50 million Americans are hypertensive (BP > mmHg). HTN in the US is present in 60% of non-Hispanic whites and 71% of non-Hispanic blacks aged ≥60 years. It is the most prevalent of the three major risk factors - HTN, hypercholesterolemia, and cigarette smoking - for coronary heart disease (CHD) the leading cause of death in the industrialized Western World. BPH is the leading cause of morbidity in elderly males. Autopsy studies demonstrate an increase in prevalence from about 25% among men in their 40s, to 80% among men in their 70s. HTN and BPH share a number of common features including increased frequency in the elderly and considerable a burden on healthcare resources. A striking feature which links HTN and BPH is the etiologic role of the sympathetic nervous system. Sympathetic tone mediated by the α-adrenoreceptor is pivotal in BP control. By selectively inhibiting vascular α-1 adrenoreceptors, thereby inhibiting the response to epinephrine and norepinephrine and thus reducing peripheral vascular resistance (PVR), selective α-1 inhibitors produce a physiological reduction in BP. Selective α-1 adrenoreceptor inhibitors with a long duration of action (t 24-hr.) produce both a gradual and sustained reduction of systolic and diastolic BP. Receptors of the α-1C subtype are also found on the urethra, bladder neck, prostate, and prostatic capsule. Selective α-1 inhibitors, by reducing the tone of prostatic smooth muscle, have the potential to improve urinary flow rate, as well as the obstructive and irritative symptoms characteristic of BPH. While there are little or no epidemiological data describing the concomitance of HTN and BPH in men, the frequent occurrence of both and their propensity to increase with age, suggests that a large proportion of elderly men may well have both conditions. An agent, which can selectively inhibit the α-1-mediated effects of the cardiovascular system and the lower urinary tract, would be expected to be beneficial in the treatment of both HTN and BPH. Studies involving patients with concomitant HTN and BPH have indeed shown that α-1 inhibitors effectively reduce BP, increase uroflow, and alleviate BPH symptoms. Since selective α-1-mediated reduction in BP is the result of a decrease of enhanced PVR, the effect on normotensive BP in the absence of an increased PVR is minimal.
