For most people, the main cause of overactive bladder is involuntary contractions of the muscle in the bladder wall (also known as the detrusor muscle). Most overactive bladder treatments aim to slow down the involuntary contractions. Medications known as anticholinergics are the main medication option for OAB.
How they work
Anticholinergics are thought to work by blocking the stimulation of the detrusor muscle that leads to involuntary contractions. However, recent research and experience using these medications for overactive bladder suggest that anticholinergics work on the bladder in other ways as well. Anticholinergics help to reduce visits to the bathroom, the strong urges to go, and the number of urine leaks.
Anticholinergics available in Canada include:
Most of these medications are available as tablets and some are available in forms that only need to be taken once daily. Oxybutynin is also available as a patch or a gel.
Side effects and how to manage them
Since these medications work in a similar way, they also share certain side effects. The most common side effects are dry mouth and constipation.
To manage dry mouth, try chewing sugarless gum, sucking on ice chips or sugarless hard candies, or using a saliva substitute (available in pharmacies). If you're still troubled by dry mouth, speak to your doctor.
To prevent and manage constipation, try increasing the amount of fibre in your diet and getting more exercise. You can also speak to your doctor or pharmacist about using medications to prevent or relieve constipation.
Drinking plenty of fluids may also help in combatting dry mouth and constipation, but the increase in fluids may affect your condition. Talk to your doctor to see if this is a viable option for you.
Who should not use these medications?
These medications should not be used by anyone who has trouble passing urine (urinary retention) or who has any condition that slows down the movement of material through the stomach, intestines, or bowel (gastric retention). People with a type of glaucoma known as narrow-angle glaucoma should not use these medications (if you have glaucoma, ask your doctor if the type you have is narrow-angle glaucoma).
Speak to your doctor if you have other stomach or intestinal problems, heart problems (including whether you or any family members have a rare heart problem called QT prolongation), neurologic disease, liver disease, or kidney disease, or if you are pregnant or breast-feeding.
As with any medication, anticholinergics may interact with other medications. Always make sure your doctor and pharmacist know all the medications you are taking (including non-prescription and herbal medications).
Knowing what to expect
When starting a new treatment, it's important to know what to expect from your treatment, including when it will start working, which symptoms it will help with, and how much you can expect it to help with your symptoms. To learn more about what to expect from your treatment, see Getting the most from your treatment, or speak to your doctor.
As of 2012, botulinum toxin is currently approved in Canada to treat overactive bladder that is a result of multiple sclerosis or spinal cord injury when anticholinergic medications have not worked or have not been tolerated. Studies are ongoing to confirm the benefits and risks of treating OAB due to other causes with botulinum toxin.
Mirabegron is a new type of OAB medication was approved in 2013 and is currently available in Canada.