Expanded use of Botox (onabotulinumtoxinA) for the treatment of leaky bladder (overactive bladder) in adults who did not respond well to anticholinergics has been approved by the Food and Drug Administration (FDA).

Anticholinergics are a class of medications that oppose the actions of acetylcholine, a neurotransmitter. These medications inhibit the transmission of parasympathetic nerve impulses; they reduce spasms of smooth muscles, such as the muscles in the bladder.

Patients with an overactive bladder experience leaking urine (bladder incontinence) because the bladder squeezes either without warning or too often. Patients commonly have a sudden and urgent need to urinate, and urinate frequently.

In the USA, about 14.7 million adults are thought to experience symptoms of overactive bladder with urinary incontinence. Anticholinergics are commonly prescribed as pills and are used by about 3.3 million patients in the United States with overactive bladder to manage their condition. However, experts say that over half of them stop taking at least one oral drug within one year, probably because they do not work properly; some also give up taking the medication because they cannot tolerate it.

Dr. Victor Nitti, Vice Chairman, Department of Urology and Director of Female Pelvic Medicine and Reconstructive Surgery at NYU Langone Medical Center, said “Overactive bladder can be a difficult condition to treat as there have been limited options for patients when currently available medications have failed to provide them with adequate relief. With the approval of Botox we have a new treatment option to offer these patients that has demonstrated efficacy in reducing urinary leakage and other symptoms of OAB with the effect lasting up to six months.”

By injecting Botox into the bladder muscle, the bladder relaxes and can store larger volumes of urine, resulting in reduced episodes of urinary incontinence.

The surgeon injects Botox into the bladder using cystoscopy. In this procedure the doctor can see the inside of the bladder so that the Botox can be accurately injected.

Scientists from Loyola University Chicago Stritch School of Medicine (SSOM) and the National Institutes of Health network found that Botox injected into the bladder muscle is twice as likely to eliminate overactive bladder symptoms in females compared to medications.

Hylton V. Joffe, M.D., director of the Division of Reproductive and Urologic Products in FDA’s Center for Drug Evaluation and Research, said:

“Clinical studies have demonstrated Botox’s ability to significantly reduce the frequency of urinary incontinence. Today’s approval provides an important additional treatment option for patients with overactive bladder, a condition that affects an estimated 33 million men and women in the United States.”

FDA experts assessed data from two clinical trials involving 1,105 patients, they all had symptoms of overactive bladder. The aim was to determine how safe and effective Botox was for the treatment of leaky bladder in adult patients. Participants were randomly selected to receive either injections of 100 units of Botox (20 injections of 5 units each) or placebo.

The human studies showed that:

  • Within 12 weeks, those in the Botox group experienced 1.6 to 1.9 times fewer episodes of urinary incontinence per day compared to those in the placebo group

  • The patients in the Botox group needed to urinate 1 to 1.7 fewer times per day than those in the placebo group

  • The Botox group patients expelled 30 milliliters more urine each time they went to the toilet than the placebo patients

The effects of the Botox treatment on reducing overactive bladder symptoms last between 135 and 168 days, according to the two clinical studies, compared to 88-92 days with placebo.

The Botox treatment can be repeated when its effects have worn off. However, repeat treatments should not occur within twelve weeks of the previous ones.

The following side effects were reported during the clinical trials:

If a patient experiences urinary retention, he/she may require a urinary catheter until the problem resolves.

Patients with overactive bladders who are being treated with Botox must not have urinary tract infection. They should be treated with antibiotics before, during and for some days after the Botox procedure in order to minimize the risk of another infection.

Botox is manufactured and marketed by Allergan Inc., California, USA.

Scott Whitcup, M.D., Allergan’s Executive Vice President, Research and Development, Chief Scientific Officer, said:

“Allergan has a long-standing commitment to study the potential of BOTOX® to treat a number of different medical conditions. With today’s approval, BOTOX® is now approved for 26 different indications in more than 85 countries. Most importantly, today’s FDA approval is a milestone in the treatment of this burdensome condition and will provide a novel option for urologists and their OAB patients.”

Botox (onabotulinumtoxinA) is a medical product that can only be obtained via a prescription. It contains miniscule quantities of a botulinum toxin protein refined from Clostridium botulinum, a bacterium. The Botox formula contains extra proteins which prevent the core toxin in Botox from degrading.

When Botox is injected at FDA-approved doses into certain muscle or glands, the Botox neurotoxin acts locally to produce an effective and safe result which lasts from three to ten months, depending on the indication and certain features of the individual patient.

Botox was approved by the FDA over 22 years ago for treating strabismus and blepharospasm (two disorders of the eye).

Botox is currently approved for the treatment the following medical conditions in the USA:

  • Abnormal head position in neck pain suffered by adults with cervical dystonia

  • Severe primary axillary hyperhidrosis (severe underarm sweating) when other medications did not work

  • Progressive muscle stiffness in the elbow, wrist and finger muscle in adults with upper limb spasticity

  • For the prevention of headaches in adults with persistent migraine (chronic migraine). Researchers from the Medical College of Wisconsin, Milwaukee reported in JAMA (April 2012 issue) that Botox injections for chronic migraine do not appear to be the amazing therapy many believe them to be. They said that Botox helps chronic migraine symptoms “a little”.

  • Urinary incontinence associated with a neurologic condition, such as spinal cord injury or multiple sclerosis who did not respond to anticholinergic medications

  • Overactive bladder symptoms among adults who did not respond to anticholinergic drugs

Botox Cosmetic (onabotulinumtoxinA) has been approved for getting rid of severe frown lines between the eyebrows (severe glabellar lines) associated with corrugators and/or procerus muscle activity in adults aged up to 65 years.

Botox has been recognized as an effective treatment for 26 different indications in about 85 countries since it was first approved in 1989.

Written by Christian Nordqvist