March 31, 2004 -- The manufacturer of a new treatment for overactive bladder says its drug may be less likely to affect the memory than currently available therapies. In a study reported late last week, patients taking Enablex showed no evidence of memory or other cognitive problems.
Researchers say the new medication called Enablex treats urinary incontinence from overactive bladder by specifically targeting the bladder muscles that control urinary urges. They also say the drug is less likely to affect the brain and have side effects such as memory problems compared with other drugs that are currently on the market. But an incontinence expert contacted by WebMD says that cannot be proven until the medications are compared to each other.
"Right now (Enablex) has a theoretical edge, but it is certainly not a proven edge," says University of Pennsylvania urology professor Alan Wein, MD. "The only way to prove the edge is by comparing it to the other drugs in head to head studies."
An overactive bladder is known to cause a sudden and uncontrollable urge to urinate frequently. With an overactive bladder, the muscles of the bladder become spastic causing bladder contractions and involuntary urine loss. They are a few treatments that can be tried in people with the condition including biofeedfack, surgery, and medications that cause bladder muscles to relax.
Although medications used to treat an overactive bladder are effective there have been isolated reports of central nervous system impairment associated with widely prescribed overactive bladder drugs such as Detrol (Pfizer Pharmaceuticals) and Ditropan (Ortho-McNeil Pharmaceuticals).
These drugs, known as anticholinergics, act on the M3 receptor and cause bladder muscles to relax. This antispasmodic effect prevents the involuntary release of urine in people with overactive bladders. But they also act on other receptors associated with brain function and heart rhythm and side effects that can be caused by these drugs include confusion, headaches, drowsiness, and rapid heart rates.
According to a spokesperson for Enablex manufacturer Novartis, the new treatment more directly targets the M3 receptor. He added that the company hopes to launch its overactive bladder drug in the U.S. this year, pending Food and Drug Administration approval.
In a study involving 1,000 patients who took Enablex, presented March 26 at the 19th European Association of Urology Congress in Vienna, Austria, researchers reported a 77% reduction in the number of incontinence episodes that resulted in the changing of clothes or pads. That's comparable to the responses seen with the currently available overactive bladder medications.
In a separate report, researchers used computerized testing to compare the impact of Enablex on thinking and memory in 129 elderly overactive bladder patients. They found no measurable differences in memory or brain function between groups that received Enablex or a placebo pill.
Cognitive Problems Rare
But Wein says there have been few reports of thinking and memory problems linked to the currently available drugs.
He also says that these problems may be underreported because they are already so common among elderly patients who take these drugs. "These problems seem to be rare, but that may simply be because nobody has done the right studies on the right populations."
Urologist Gary Leach, MD, says he has seen little clinical evidence of thinking or memory problems associated with the available overactive bladder drugs. Leach is director of the Tower Urology Institute for Continence at Cedars Sinai Hospital in Los Angeles.
"I don't see cognitive impairment as a major issue with my patients, and I think that is typical of what is being seen in the general population of patients treated for overactive bladder," he says.