A Close Look at the Medications Used for Benign Prostatic Hyperplasia (BPH)

Jay Motola Health Pro
  • Studies of the drug phenoxybenzamine, a non-specific alpha blocker, led to a better understanding of the control of the smooth muscle tone of the prostate and the opening to the bladder, the bladder neck. Alpha blockers cause a relaxation of these structures and therefore permit urine to flow more freely out of the bladder and into the prostatic urethra.

     

    In 1976, Pfizer introduced Minipress (prazosin HCL) in the United States for the control of hypertension. This drug is a non-specific blocker of the alpha adrenorecptors. Drugs in this category cause a relaxation of smooth muscle cells that are located in the walls of various blood vessels. Attempts were made to utilize these drugs and exploit their alpha blocking capabilities to exert an effect on the lower urinary tract; however these efforts were limited by the side effect of hypotension and dizziness.

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    In 1987 Hytrin (terazosin) was introduced.  This alpha-1 blocker is non specific and has a greater propensity to affect urinary tract tissue instead of the vascular tissue. The blood pressure lowering property remained an issue, albeit less so than the predecessor phenoxybenzamine as this agent still does have some effect on the smooth muscle that is contained within vascular tissue.


    This drug is available in several different doses, and by gradually increasing the dose, some of the drugs ability to lower blood pressure were eliminated.  Doxazosin (cardura) is another alpha 1 blocking agent that has a similar safety profile as terazosin however it has been shown to have little blood pressure lowering effect in patients who have normal blood pressure.  It does however exert an anti-hypertensive effect in patients with hypertension.  It is less associated with the positional effects on blood pressure that is exhibited in patients using terazosin.

     

    More recently selective alpha -1 blocking drugs have been released.  Drugs such as tamsulosin (Flomax) and alfuzosin (Uroxatral) have been introduced.  These agents do not exert any antihypertensive side effects, are very effective in reducing symptoms of outlet obstruction and are very well tolerated with few side effects.

     

    Other categories of drugs exert an effect on the prostate, such as 5 alpha-reductase inhibitors also exist and these agents will be discussed in a future blog.

Published On: July 02, 2007