FDA Approves Rapaflo for the Treatment of Symptoms Due to an Enlarged Prostate Gland

Published: Fri Oct 10 00:00:00 +0000 2008

The U.S. Food and Drug Administration today approved Rapaflo (silodosin) capsules for the treatment of symptoms due to benign prostatic hyperplasia (BPH), a condition also known as an enlarged prostate.

BPH is a male disease wherein the prostate gland – located between the bladder, which stores urine, and the urethra, the tube through which urine exits the body – enlarges in men as they age. By age 50, roughly 50 percent of all men suffer from BPH. By age 80, that number jumps to 75 percent.

"Benign prostatic hyperplasia can seriously impact the quality of life of men as they age," said George Benson, deputy director, Division of Reproductive and Urological Products, FDA. "This product will provide another treatment option for men suffering symptoms of an enlarged prostate."

As men age, their prostate gland enlarges and begins to press against their urethra. This pressure can impede the flow of urine and make it difficult to eliminate it from the body. In the early stages of BPH, the disease can also create a need to urinate more frequently, or cause dribbling after urination. BPH can also lead to an increased risk of urinary tract infections and urinary retention. Urinary retention can damage the kidneys and cause urinary tract infections by mixing urine from the ureter with urine from the bladder that is heavily laden with bacteria.

Rapaflo works by blocking the alpha-1 adrenoreceptors in the prostate, bladder, and urethra. By blocking these receptors, this treatment allows the smooth muscle in these tissues to relax, resulting in a reduction in BPH symptoms.

Rapaflo will be available in a once-daily capsule. An 8 milligram (mg) daily dose is recommended for men who do not suffer from kidney or liver impairment. A 4 mg daily dose will be available for men with moderate kidney (renal) impairment. Rapaflo is not recommended for men with severe kidney (renal) or liver (hepatic) impairment and is not approved for pediatric use.

The safety and efficacy of Rapaflo were shown in two 12-week, randomized, double-blind, placebo-controlled, multicenter studies using an 8 mg daily dose of Rapaflo. There were 923 male participants in the studies with an average age of 64.6 years. Of the 923, 89.3 percent were Caucasian, 4.9 percent were Hispanic, 3.9 percent were African-American, 1.2 percent were Asian and 0.8 percent were identified as "other." The participants were randomized and, of the 923 patients, 466 received an 8 mg daily dose of Rapaflo. In these studies, Rapaflo produced a statistically significant improvement in BPH symptoms and urinary flow rate when compared to placebo.

It is important that patients know and health care professionals recognize that cancer of the prostate gland and BPH cause many of the same symptoms and that these two diseases, BPH and prostate cancer, frequently co-exist. Therefore, patients thought to have BPH should be examined prior to starting therapy with Rapaflo to rule out the presence of prostate cancer.

The most common side effect seen with Rapaflo is reduced or no semen during orgasm. This side effect does not pose a safety concern and is reversible with discontinuation of the product. Other side effects included dizziness, light-headedness, diarrhea, orthostatic hypotension (drop in blood pressure upon standing), headache, nasopharyngitis (a contagious viral infection of the nose and upper portion of the throat), and nasal congestion. Patients planning cataract surgery must notify their ophthalmologist that they are taking Rapaflo because of the possibility of a condition called Intraoperative Floppy Iris Syndrome (IFIS), a complication associated with cataract surgery in patients on alpha-1 adrenoreceptor blocker medications. In IFIS the iris of the eye becomes limp and moves in waves as a result of increases in fluid levels within the eye. This can result in a painful and extended recovery period in those who have undergone cataract surgery and a reduction in visual acuity (sharpness). Patients on alpha-blockers or those who have severe kidney or liver impairment should not use Rapaflo.

Consumers and health care professionals can report adverse events to the FDA's MedWatch program at 800-FDA-1088, by mail at MedWatch, HF-2, FDA, 5600 Fishers Lane, Rockville, Md 20852-9787, or online at www.fda.gov/medwatch/report.htm.

Rapaflo is manufactured by Watson Pharmaceuticals Inc., Corona, Calf., and will be distributed by Watson Pharma Inc. under license from Kissei Pharmaceutical Co. Ltd., Nagano, Japan.

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