Most common lower urinary tract symptoms in post-middle aged males are due to benign prostate enlargement. Pharmacological treatments include *alpha blockers and 5-alpha reductase inhibitors (5ARIs). 5ARIs have been shown to reduce the size of the prostate gland. 5ARIs block the transformation of testosterone into dehyrotestosterone, an attempt to prevent division of the cells in the prostate.

Symptoms of prostate enlargement include *voiding symptoms (urination) and storage symptoms. Although storage symptoms are more common, most of current treatments focus on voiding symptoms, which are related to the detrusor muscle**. The detrusor causes bladder outlet obstruction and treatment improves the voiding problem. This study was done to see if 5ARIs can also relieve storage symptoms by comparing one group of men who received only alpha blocker and another group which received alpha blocker plus 5ARI therapy. (738 men were studied.)

The patient’s voiding symptoms were significantly reduced by treatment, and storage symptoms were also significantly improved by treatment in both groups. No significant change was seen in storage symptoms scores between the groups.

In general, a combination of an alpha blocker and a 5ARI is used to treat a large prostate, with results being better in the larger prostates. There were no significant differences in the results of the two different groups of patients.

CONCLUSION: For benign prostatic hyperplasia, combination therapy with alpha blockers and 5-alpha reductase inhibitors are effective. However “5ARI does not exert a significant effect on storage symptoms in BPH patients”.

NOTES: Saw palmetto and kudzu are 5-alpha reductase inhibitors.

*Alpha blockers are drugs which antagonize the androgenic receptors, thereby relaxing muscle tissue in the area of the prostate and bladder neck. They can relax blood vessels and smooth muscle.

**Voiding symptoms include flow rate, bladder wall pressure at maximal flow, residual urine left after voiding, and bladder outlet obstruction. Storage symptoms included urine volume at the first desire to void, maximum capacity of the bladder and involuntary bladder wall contractions.

***The detrusor muscle is the muscle of the wall of the urinary bladder which causes the bladder to contract. (Sitting to void increases the contracting power of the detrusor muscle.)

Pharmaceutical alpha blockers included doxazosin, tamsulosin, terazosin and alfuzosin, while pharmaceutical 5ARIs included finasteride (or dutasteride).

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PMID: 22087424.

Summary #699.