Multiple sclerosis (MS) is a progressive condition that involves the immune system attacking and destroying healthy nerve cells. The condition causes changes in muscle function — known as spasticity — that can affect your body’s ability to move on your command and cause repetitive movements, such as bladder spasms.

In addition to oral medications to treat MS, doctors also use botulinum neurotoxin (Botox) for MS to treat spasticity.

Keep reading to learn more about how Botox may help treat your MS symptoms.

The FDA approved three formulations of botulinum toxin injections to treat multiple medical conditions, including:

  • onabotulinum toxin A (Botox)
  • abobotulinum toxin A (Dysport)
  • incobotulinum toxin A (Xeomin)

Each of the above formulations can help stop the transmission of nerve signals from the brain to the affected muscles. The muscles usually stop tensing or contracting, allowing them to relax.

People may often know Botox as a treatment for wrinkles. But doctors can use Botox in many capacities, such as to reduce sweating and treat spasticity after stroke or in people with MS.

There are few data about how effective Botox is for treating MS.

But some doctors use it to help people with MS find relief from spasticity. And doctors usually use Botox as an MS treatment alongside other medications to relieve spasticity.

Doctors use Botox to treat spasticity in specific muscle groups. This can include individual muscle groups, including:

  • ankle flexors
  • biceps or elbow flexors
  • fingers flexors, including the thumbs
  • toe flexors
  • wrist flexors

Doctors can also use Botox to treat people with MS who have overactive bladder (OAB), tremors, and migraines.

The effects of MS can cause overactive bladder contractions — and this can lead to incontinence, frequent urination, or feeling like you need to pee constantly.

A 2018 study suggested that injecting Botox into the intradetrusor muscle in the bladder reduces urinary incontinence and improves quality of life.

One of the main considerations in using Botox for MS is how the condition affects muscle groups. If you have spasticity in several areas, Botox may not be an effective treatment because a doctor would have to inject too much. But if you have limited spasticity that affects a certain muscle group, Botox may be effective.

The procedure to inject Botox for MS depends on where the doctor injects the Botox. For example, if your doctor injects Botox into an arm or leg muscle, they will likely do the following:

  1. Identify the most affected muscles. They may use an ultrasound or electromyography (EMG) machine to identify muscles and find the best place for the injection.
  2. Inject Botox into a muscle. They may inject into the muscle using a small, fine needle.
  3. Place several small injections around the muscle. The reason for the several small injections is that Botox doesn’t usually spread far beyond where the doctor injects it.
  4. Instruct you to limit some activities. The reason for the instruction is that certain activities can reduce the injection effectiveness.

For Botox injections in the bladder, the procedure typically involves using a local anesthetic injection. But some people may prefer general anesthesia or no anesthesia at all.

Botox doesn’t relieve spasticity right away. It can take up to 1 to 2 weeks before you notice its effects.

The most immediate side effects after injection include:

  • bleeding, usually minor
  • bruising
  • muscle soreness
  • pain at the injection site

After receiving Botox injections to treat bladder symptoms, people often report experiencing urinary tract infections (UTIs) as a side effect.

UTIs occurred in about 25.8 percent of participants in a 2018 study on the effectiveness of using Botox to treat urinary symptoms related to MS.

Rarer side effects reported in the study above included:

Botox injections for MS offer several potential benefits, including:

  • partial muscle paralysis that can reduce spasticity symptoms
  • pain relief that may last for 3 to 4 months
  • enhanced flexibility and range of motion in affected joints

But there are also possible downsides of using Botox to treat MS that you may want to consider:

  • Botox results may last several months, but you will require repeated treatments. Over time, Botox can become less effective as your body adjusts to breaking it down.
  • Severe spasticity symptoms are typically less responsive to treatment with Botox.
  • You may experience disruptive side effects, such as significant muscle weakness.

Botox isn’t as invasive as surgery, but it does involve injecting a substance into your body.

For this reason, it isn’t usually a first-line treatment for MS symptoms. If your symptoms don’t respond well to other treatments, then Botox may be an effective option.

Sometimes, spasticity can cause severe muscle contractions. This means that it can be difficult to move muscles. When the severe muscle contractions occur, Botox therapy may not be effective.

An estimated 2.8 million people in the world have MS. Doctors use Botox to help relieve spasticity symptoms in the upper and lower limbs, as well as the bladder.

Talk with a doctor if you have MS and believe that Botox may help your spasticity — especially if other treatments haven’t worked or been very effective.