Overactive Bladder (OAB)


Handout on Overactive Bladder



Overactive bladder (OAB) is a condition characterized by the sensation of needing to urinate in the absence of a full bladder often associated with urinary frequency (having to void less than every 2 hours), urinary urgency (difficulty postponing urination) and sometimes even leakage. Most importantly, OAB is a 'diagnosis of exclusion' - this means that other causes such as infection, neurologic problems or anatomical problems have been evaluated and are NOT present. Please note that it is not abnormal to void up to 8 times a day or every 2 hours or so - but the frequency of urination is also determined by the amount of fluid that is consumed. People who drink high volumes of any fluid (but especially caffeine-containing fluids) can expect to urinate frequently and this is not considered abnormal.  Likewise, waking at night once or twice is not considered abnormal. An increased frequency of urination at night (nocturia) can be a part of OAB, but there are also many other causes of nocturia.


OAB is very common, affecting 1 in 5 people over age 35.  It is more common with age and affects men and women equally.




"Primary" OAB is due to involuntary bladder contractions.  In the majority of cases, no underlying cause is found.  There are certain conditions which may lead to "secondary" OAB, including bladder infection, stones, neurologic disorders, obstruction and, very rarely, a bladder growth.


Diagnosis & Evaulation


The evaluation is aimed at quanitifying the symptoms and looking for potentially reversible or significant causes of the symptoms.  Evaluation may include:




Primary OAB treatment depends primarily on behavioral and lifestyle changes to optimize bladder health.  These are things you can do to help yourself and will likely need to do this long term for best outcomes.  Click on the links below for more information:


  1. dietary modification: bladder irritants
  2. behavioral therapy for the bladder
  3. pelvic floor exercises
  4. pelvic floor physiotherapy

There are several medications which may provide some symptom relief.  They all fall under the same class of medication called "anticholinergics".  Potential side effects include dry mouth, constipation, dry eyes, eye pain (if history of glaucoma), cognitive changes or confusion (especially in the elderly).  Your urologist will discuss these with you further to help you decide if this is a reasonable option for you.


In severe OAB cases, where there is no response to lifestyle changes and medications and symptoms are severe, additional options may be considered.  These include botox injection into the bladder, neuromodulation techniques, surgery and catheterization.


How to Take the Medications Used to Treat OAB


Successful use of OAB medications requires some input from you. The goal of medication is to improve your symptoms of urinary urgency, frequency and leakage while minimizing the side effects (mainly dry mouth, dry eyes and constipation). This requires picking the medication that has the best fit for you and making sure you are taking the right dose at the right time.


MOST OF THE MEDICATIONS REQUIRE A 3-6 WEEK TRIAL. Remember that you are in the 'drivers seat' when taking these medications. Only you can decide if you should continue - you do this by trying the medication and see if the benefits (less urinary frequency, incontinence, urgency, etc.) outweight and downsides (side effects, cost, inconvenience). It may be that you take 'on-demand' rather than regularly (see below).


  1. Picking the right strength. Most of the medications come in different strengths. You may increase the dose up to the maximum dose, but do not increase it beyond that with out consulting your urologist.
  2. Regular vs. on-demand dosing. These medications generally work best if taken continuously, but there is no reason why you cannot take them 'on demand' -  only when you need them. You may find that your symptoms are really only a problem when travelling or out at social events, for example, and manageable other times. You may take them only at these times.
  3. Timing of dosing. Many of the medications are once-daily formulations. If so, they are usually best taken before bed to minimize side-effects. However, they may be taken at any time during the day. 
  4. Frequency of dosing. Most OAB medications are once-daily dosing so frequency is simple. There are 2 medications, however, where the frequency and amount can be varied significantly.
    1. Ditropan (oxybutyinin), however, is short acting and can be taken up to 3 times per day. Each pill is usually 5 mg and these can be easily split into 2.5 mg tablets since they are scored. The dosage you take should not exceed 15 mg per day (3 full pills) without discussion with a urologist. You may take any amount less than that at a frequency of your chosing. For example, the best dose for one person might be 5 mg three times per day. For another, it may be 2.5 mg twice daily. Others might do best with 5 mg first thing in the morning. Basically, you can mix whatever dose and frequency works best for you, so long as you do not exceed 15 mg per day. This may require some trial and error to find what works best.
    2. Oxytrol patch. This is a skin patch which is applied every 3-4 days. It can sometimes remain effective for up to 5 days. The patch can also be cut in half. Therefore, anywhere from 1/2 to a full patch can be used. In some circumstances, more than a full patch will be prescribed.


Medication Pill size Usual Dose Maximum Daily Dose*
Ditropan (oxybutyinin) 5 mg 2.5-5 mg tid 15 mg
Ditropan XL 10 mg 10 mg daily 10 mg
Uromax 15 mg
15 mg daily 15 mg
Detrol LA (tolterodine) 2 mg, 4 mg 4 mg daily 4 mg
Detrol (tolterodine) 2 mg 2 mg bid 4 mg
Enablex (darifenacin) 7.5 mg, 15 mg 7.5 mg daily 15 mg daily
Vesicare (solifenacin) 5 mg, 10 mg 5 mg daily 10 mg daily
Oxytrol patch 3.9 mg 3.9 mg every 3-4 days 3.9 mg every 3-4 days
Sanctura (trospium) 20 mg 20 mg bid 40 mg daily
Sanctura XR 60 mg 60 mg daily 60 mg daily
Toviaz 4 mg, 8 mg 4-8 mg daily 8 mg daily
Myrbetriq 25 mg, 50 mg 50 mg daily 50 mg daily

bid = twice daily; tid = three times per day; * do not exceed without consulting your physician


If you find that a higher dose of a once daily medication works best for you and are taking 2 pills of the lower dose, make sure you let your doctor know since they can prescribe the higher dose as a single pill. The cost will be much less.


Most importantly, these medications are designed to help your symptoms. If the side-effects outweight the benefit, you may stop them after consulting your urologist. There are exceptions to this guideline - especially in those patients with neurogenic bladder (e.g. from stroke, spinal cord injury or other neurological conditions). In these cases, the medications may be necessary to maintain the health of your kidneys. As always, consult your urologist or family physician first.


BOTOX Bladder Injections


Injection of Botox into the bladder wall is highly effective for treating certain types of OAB symptoms. The procedure can be done on an outpatient basis, usually taking no more than 5 minutes, is usually uncomplicated and are not associated with the most bothersome side-effects which anticholinergic medications are (dry mouth and constipation). Check with your urologist to see if it might work for you.


More information on Botox here.



The premise is the nerve stimulators affect the nerve signals to the bladder. Neuromodulation techniques include transcutaneous electrical nerve stimulation (TENS). Often TENS patches are placed over the sacrum to stimulate the nerves to the bladder. This is an intensive therapy. It involves roughly 20 minutes of stimulation twice per day for 6-12 months. Response rates are 10-50%. 


Other neuromodulation techniques include posterior peripheral tibial nerve stimulation. This involves a weekly visit for 12 weeks. A needle is placed in the lower leg to stimulate the posterior tibial nerve which modulates the same nerve plexus that affects the bladder. This can reduce overactivity symptoms by up to 70%. Generally this is reserved for patients with refractory overactive bladder which has not responded to other therapies. This is currently available in British Columbia throught the Bladder Care Center at UBC.


Sacral neuromodulation or Interstim (implanted electrodes in the sacrum) stimulate ths nerve plexus around the sacrum which also affects the bladder. Currently this is not offered in British Columbia but is available in Alberta



On the Web

General Urology Web Sites

www.overactivebladder.ca - this website gives an excellent overview of OAB and treatment options.