Medical management of benign prostatic hyperplasia: a review

Benign prostatic hyperplasia (BPH) is a common disease affecting elderly men with 70% of men over 70 years showing microscopic evidence of hyperplasia. Transurethral resection of the prostate is the gold standard treatment. Medical management of BPH has involved the use of plant extracts, amino acids, kampo and animal organ preparations in various countries with unsatisfactory results. The use of alpha adrenergic antagonists dates back twenty years representing a major breakthrough in the treatment by relaxation of the dynamic contraction of smooth muscle component of prostatic obstruction. The evolution of alpha antagonist therapy resulted in clinical trials with selective antagonists such as prazosin, alfuzosin, indoramin, terazosin and doxazosin all of which achieve similar effective relief of obstructive symptoms as phenoxybenzamine, but with fewer side effects related to postural hypotension. 5-alpha reductase inhibitors, finasteride and episteride, recently synthesised act on the static component of obstruction caused by the enlarging prostate. They inhibit conversion of testosterone to the potent intracellular androgen dihydrotestosterone (DHT) resulting in the reduction of prostate volume and improvement of obstructive symptoms. Clinical trials with finasteride for three years indicate that 63% of patients had a reduction of greater than 20% in prostatic volume and 42% had a decrease of greater than 30% with a mean increase peak flow rate of 2.4 mls/s equivalent, to 20 years reversal of disease progression.