Guide to Bladder Botox for Overactive Bladder

In Overactive Bladder (OAB), nerve signals from the bladder make you feel as if your bladder is full even though you may have just emptied. These signals can cause you to feel like you have to urinate urgently and can lead to urinary leakage. The nerve endings are the target of medications treating OAB, though in some patients, medications may not be able to control the signals or may cause side effects that limit treatment. Botox is injected into the bladder lining and can very effectively block these nerve messages at the level of the bladder. Unlike other OAB medications, Botox has a more direct effect on the bladder and uncommonly causes side effects outside of the bladder. It works though a different mechanism from medications you take by mouth, so Botox may be effective even in patients who have not improved with medications taken by mouth.

Botox is used in people with moderate to severe Overactive Bladder who have refractory symptoms (either they have not seen satisfactory improvement with medications and behavior therapy or they have intolerable side effects). Botox dosages are measured in units. Today, most patients with OAB are first injected with 100 units throughout the bladder using many locations within the bladder to insure that the Botox is well-distributed. The dosage can be increased (or decreased) depending on the response. Note that Botox may be used in other bladder conditions including neurogenic bladder, and the common starting dose may be different in those patients.

Botox is injected though a needle, much like any other injection you might receive such as a flu shot. However, because the location is inside the bladder, a long scope called a cystoscope is used to visualize the bladder and guide the injections. Most patients tolerate having this performed in the office after numbing medicine is placed in the bladder. Others may prefer light sedation during the injections. Patients can choose whichever they prefer. After about 2 weeks, patients who will respond usually begin to see improvement. Like all treatments for OAB, Botox is not a permanent cure for the symptoms. Repeated treatments are necessary and are usually about 6 months apart, though some patients will require injections more or less often.

There are numerous studies of bladder Botox that frequently have differences in how much Botox was used, where in the bladder it was injected, the type of symptoms that were being treated and even how success was defined. This makes it difficult to give one number when asked about success for Botox in the bladder. Success is often reported as a 50% reduction in symptoms (someone with an average of 4 daily bladder leaks would have to decrease to 2 or less per day). When looking at all of the studies together, the range of response is around 60-80% of patients showing at least 50% improvement and half of patients seeing 75% reduction in symptoms. For patients who have an incomplete response to a standard injection of 100 units for OAB, subsequent treatments can increase the amount of Botox that is injected. Higher doses may be associated with higher rates of unwanted side effects, however.

The improvement seen with Botox is impressive given the fact that the response rates are seen in patients who have failed previous attempts at medication therapy (often multiple medications) and also have moderate to severe symptoms. Botox is able to effectively treat even those patients who have few other options. The number of patients who see at least 75% reduction in symptoms is also notable.

The most common risk associated with Botox injections into the bladder is development of urinary tract infection. There may be several reasons for this risk. Simply putting a cystoscope into the bladder to perform the injection is a risk of a urinary tract infection. Botox can also make it more difficult to empty your bladder which increases the chances of developing a UTI. So, an antibiotic is prescribed for you to take for the few days after your Botox treatment, to try to reduce this risk.

Because of the way in which Botox affects the nerves of the bladder, trouble urinating and emptying the bladder is another possible risk. This risk is probably related to the amount of Botox injected and lower doses of Botox should result in lower rates of emptying problems. This is the main reason why most people begin with 100 units of Botox to treat Overactive Bladder. Trouble urinating and emptying your bladder can become so severe that some people may even need to use a catheter to empty. this effect wears off over time.

Across the many studies on bladder Botox, there are differences in how much Botox was used, where it was injected in the bladder and what type of patient was injected. Just as with effectiveness, all of those differences can make it difficult to give a single number for risks associated with Botox. However, it is thought that, with an injection of 100 units, most people have about a 10% risk of having some trouble urinating and 3-6% risk of having to catheterize at least one time. Both of these effects are not permanent.

I would make a few points about Botox and the risks of urinary retention (not emptying your bladder). First, while it is not a common complication, it is bothersome enough to most people that this risk should always be discussed with anyone who is considering this therapy. I think it is something every patient would want to know about to make an informed decision. However, it is also important to note that if 3-6% of patients may need to catheterize, that is the same as saying 94-97% will not. The risk of retention should be considered but should not scare patients away from the therapy.

As with all advanced therapies for Overactive Bladder, there are advantages in meeting with a specialist in bladder health to treat refractory symptoms. A doctor who has training and experience in bladder disorders can perform a comprehensive evaluation to be sure that the symptoms are actually caused by Overactive Bladder. Other bladder disorders can result in frequent urination, urgent urination and urinary incontinence. If a patient is not responding to therapies such as behavior changes and medications, it may be beneficial to pursue a more in-depth evaluation to confirm the diagnosis, especially before proceeding to advanced therapies. Patients who have something blocking their bladder, for instance, could be made considerably worse by injecting Botox.

Treating refractory OAB with a bladder specialist may also offer more options to patients. Someone who focuses on bladder health will be able to offer all of the advanced therapies for OAB insuring that you are able to choose the therapy that best fits your needs.