Long-term treatment with a combination of two medicines can help two out of three men who suffer from an enlarged prostate, a discovery that could benefit millions of men, researchers said on Wednesday.
“Two drugs are better than one,” said Darracott Vaughan in an editorial in the New England Journal of Medicine, which published the industry-sponsored study of 3,047 men treated at 20 U.S. medical centers.
About half of all men over 50 experience urination difficulties when the walnut-sized prostate becomes enlarged, and one in four men with “moderate” symptoms usually require surgery within three years.
Drugs known as alpha blockers provide some relief, but don’t stop the growth of the prostate. A second class of drugs, known as 5-alpha-reductase inhibitors, can reduce the size of the prostate by 20 percent, but often take six to 12 months to be effective, may reduce libido and can cause erection problems.
The new study, led by John McConnell of the University of Texas Southwestern Medical Center at Dallas, found that when the two drugs were used in combination for more than four years, it cut by 66 percent the risk that the condition, known as benign prostatic hyperplasia, would worsen, compared to men who took a placebo.
“A 66 percent reduction in the risk of anything in medicine is pretty substantial,” said co-author Claus Roehrborn, also at the University of Texas.
Roehrborn, like half of the 26 study authors, has financial ties to the manufacturers of the drugs studied.
The alpha blocker used in the study, doxazosin, sold under the brand name Cardura by Pfizer Inc., reduced the risk of benign prostatis hyperplasia progression by 39 percent and caused some dizziness, fatigue and low blood pressure. The 5-alpha-reductase inhibitor was finasteride, a Merck & Co. Inc. drug marketed under the name Proscar.
It had a similar effect by itself, but sexual side effects appeared in 10 percent of the men taking that drug.
It’s not clear whether the double-drug regimen will become standard therapy anytime soon.
McConnell told Reuters that men who have urination problems plus an enlarged prostate should probably take the two drugs. In his study, 80 percent of the patients fell into that category. The rest only had symptoms, so treatment with an alpha blocker should be enough.
Vaughan cautioned that prostate tumors that appear during therapy with finasteride tend to be advanced.
“The prudent physician needs to counsel men carefully before they begin combination therapy, weighing the benefit of preventing the progression of benign prostatic hyperplasia against the potentially increased risk of high-grade prostate cancer,” said Vaughan, a urologist at Cornell University.
He said alpha blockers like doxazosin will probably continue to be the initial treatment because they rapidly relieve symptoms, they are easy to give, and have few side effects.
But McConnell, in an interview, said he doesn’t believe that finasteride affects the risk of developing a deadlier form of prostate tumor.
He said having an enlarged prostate does not increase the risk of prostate cancer.