Botox for the Bladder

Background

Botox has been used for decades for certain muscle disorders and in cosmetic procedures to treat wrinkles. It has been used for injection into the bladder muscle for bladder overactivity conditions since the 1990’s.  It acts at the interface between nerve and muscle.  Botox blocks the release of neurotransmitters by nerves, which causes temporary muscle paralysis or weakness. In the bladder, the mechanism of action is less clear and may relate to changes in sensation rather than motor function.

Botox is used for many medical conditions. Its use in the bladder is an 'Off-Label' use which means that formal regulatory approval from the government of Canada has not been attained. This does not mean that there is an absence of evidence to support usage but simply that Allergan (the company which manufactures Botox) has not gone through the regulatory process (as of 2011). It should be noted that many drugs are used off label. Botox is used for temporal headaches and spastic musculoskeletal conditions such as cerebral palsy.

Procedure

Botox is injected into your bladder muscle with a simple, out-patient procedure which uses a specialized scope and needle injection set.  The Botox is suspended in normal saline and then injected under the mucosa throughout the bladder base. The procedure takes about 15 minutes or less and can be done under local anesthesia, sedation or general anesthesia. In the vast majority of patients, it can be done under local anesthesia on an outpatient basis.  Rarely, a catheter will be required for a couple of days after the procedure.

During the procedure, a slight staining with each injection can be felt. There may be some blood in the urine for a few days following the procedure. Antibiotics to prevent infection are prescribed.

The amount of Botox injected will depend on prior response. In general, a "start low and go slow" approach is used. It is fairly simple to come back for a repeat injection and started with a low dose significantly minimizes the chance of urinary retention. The maximum dosage over a 9 month period is usually kept below 500 units of Botox.

Goals of the Procedure

Botox can be used to treat just about any bladder condition which results in urge incontinence or urgency/frequency. These included symptoms caused by involuntary contractions of the bladder muscle - OAB or neurogenic bladder. The most benefit is seen in patients who have a neurologic underpinning (such as stroke, myelomeningocele, spinal cord injury) and have demonstrable bladder spasticity on urodynamic testing. Your urologist may order urodynamics prior to recommending Botox injection. 

The benefits usually last for 6-9 months, and then the procedure may need to be repeated if successful.  Studies have shown that about 2/3 of patients benefit from this approach.

Risks of the Procedure

The risks include blood in the urine (may last several days after procedure) and urinary tract infection. The effect of the Botox on the bladder muscle may vary between individuals and also depends on the dose used.  Usually, it is best to start with a low dose.  The response may vary from no change in symptoms to complete inability to void.  

Inability to void is a risk any time that Botox is injected. Fortunately it is transient and resolves on its own - though may take a couple of months. During that time you may require a urethral catheter or need to self catheterize. The risk of urinary retention depends on your circumstances and increases with the dose of Botox. With 100 units of Botox A, the general risk of transient urinary retention is less than 10%. With 200-300 units the risk rises to 30-40%. Interestingly, subsequent injections carry a much lower risk of urinary retention even when the same dose is used - about 5% risk. 

Other Options

Behavioral therapy, dietary changes, physiotherapy and medications to treat OAB have usually already been tried by the time one is considering Botox injections. Neuromodulation of the sacral nerves is another option but comes with a high cost, requires minor surgery and is not currently offered in BC. Other options include permanent catheters, major bladder surgery, or just living with the problem.

Cost and Insurance Coverage

If you decide to move forward with Botox injections, a request for ‘Special Authority Coverage’ will be made to Pharmacare. They typically require 2 (two) separate 3 month trials of an oral antispasmodic medication for overactive bladder as well as documentation of the symptoms. The medication trial is confirmed by reviewing prescription records; Pharmacare frequently rejects trials that involved medication samples. The wait time for them to evaluate a submission is 3-6 months (for the purposes of data processing they only ‘start the clock’ when they look at the file, not when it was sent or received). If approval is granted, it may be limited to a short time window (6 weeks) which provides only a short time to move forward with the injection procedure.

Extended health insurance may provide coverage if Pharmacare rejects a request. Some patients request to move forward with injections either through extended health or self-pay because the approval process from Pharmacare may take months. If you require completion of forms for insurance purposes we will charge a nominal fee to compensate for the time it takes to do this.