Medications for treating urinary incontinence increase sphincter or pelvic muscle strength or relax the bladder, improving the ability to hold more urine. Medications are prescribed for all kinds of incontinence, but they are generally most helpful for urge incontinence.
Medications Used for Urge Incontinence
Anticholinergics work in the following ways:
- Inhibit the involuntary contractions of the bladder
- Increase capacity of the bladder
- Delay the initial urge to void
These drugs can produce small but significant improvements. Anticholinergic medications carry certain side effects, most notably dry mouth and constipation.
- Oxybutynin (Ditropan, Oxytrol)
- Tolterodine (Detrol)
- Hyoscyamine (Levbid, Hyomax)
- Trospium (Sanctura, generic)
- Darifenacin (Enablex)
- Solifenacin (Vesicare)
- Fesoterodine (Toviaz)
Extended-release forms of oxybutynin (Ditropan XL) and tolterodine (Detrol LA) are available. They improve continence and have fewer adverse effects than short-acting forms. A skin patch form of oxybutynin (Oxytrol) is another option. It may have fewer side effects, such as dry mouth and constipation, than the pill form. Oxybutynin is also approved for pediatric use in children ages 6 and older.
Side effects of anticholinergic drugs include:
- Dry eyes (a particular problem for people who wear contact lenses; patients who wear contacts may wish to start with low doses of medication and gradually build up)
- Dry mouth
- Rapid heart rate
- Confusion, forgetfulness, and possible worsening of mental function, particularly in older people with dementia, such as those with Alzheimer’s disease
- Hallucinations, possibly, especially for children and older adults; doctors should monitor patients for this symptom
Tricyclic antidepressants, such as imipramine (Tofranil, generic), may help both urge and stress incontinence. They act as anticholinergic drugs and relax the bladder. They also strengthen the internal sphincter. These drugs should be used carefully. They pose some risk for adverse effects on the heart and possibly the lungs, and they have other severe side effects in older adults. These antidepressants produce side effects similar to anticholinergic drugs, and may cause drowsiness. They may also cause overflow incontinence in some people.
Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs)
SNRIs are specially designed antidepressants that are similar to tricyclics but do not have the same side effects. They target the neurotransmitters serotonin and norepinephrine, which are thought to play key roles in the normal action of bladder muscles and nerves. Increased neurotransmitter activity stimulates the nerve that controls the urethral sphincter. The SNRI duloxetine (Cymbalta) is approved in Europe for treatment of stress urinary incontinence. It is approved in the U.S. for other conditions, but not for stress urinary incontinence. Nevertheless, it is sometimes prescribed off-label for stress urinary incontinence. The FDA is investigating whether duloxetine can increase the risk for suicidal behavior.
Drugs for Refractory Urge Incontinence
Individuals who have failed conventional, conservative therapy are diagnosed as having Refractory Urge Incontinence. Botulinum (Botox), the deadly toxin that sometimes contaminates improperly cooked foods, is also a powerful muscle relaxant. Botox can be injected directly into the muscular wall of the bladder, relaxing the muscles and helping to control overactive bladder that causes urge incontinence. Its limitations lie in its side effects (voiding dysfunction–up to 25-30%) and in its short-term effect, meaning repeat injections are necessary.