Botulinum toxin (Botox)

Botox, or botulinum toxin, is often best known for its use in cosmetic procedures. However, Botox injections can also be used to treat muscle stiffness, spasms and bladder accidents in MS.

Botulinum toxin is a naturally occurring chemical that’s made by bacteria. The toxin itself is highly poisonous but, in small doses, it can be used to treat certain MS symptoms. It’s been used to treat symptoms like muscle stiffness for decades.

There are several different types of the toxin. Botulinum toxin A is the one most frequently used in MS.

In small doses, botulinum toxin can be safely used to treat several symptoms in MS, including:

• muscle stiffness and spasms
• bladder symptoms – specifically, bladder accidents (incontinence) and feelings of urgently needing to wee
• tremor
• trigeminal neuralgia.

Botulinum toxin is usually used when you’ve tried other treatment options, such as oral medications, and they haven’t worked for you.

When botulinum toxin is injected into a muscle, such as your bladder wall or calf muscle, it stops nerve messages getting through to that muscle. This relaxes and weakens the muscle and stops it contracting.

This relaxation of the muscle is temporary and will gradually wear off. This happens as the damaged nerve ends regrow and start sending messages again. At this point the injections can be repeated.

Effects usually last for several months. Exactly how long it lasts depends on where it's been injected and what symptom it's being used for. 

Botulinum toxin must be given by an appropriately trained health professional. Using a fine needle, they will inject a small dose of the toxin directly into the effected muscle or a small group of muscles. The effect of the toxin gradually builds up over a couple of weeks.

For muscle stiffness and spasms, you may be given some exercises and stretches to maximise the effects of the injections.

For bladder problems, such as incontinence, botulinum toxin is injected into your bladder wall from the inside. The procedure is usually carried out under local anaesthetic. A fine tube, containing a very small telescope, is inserted into your bladder via the urethra (the tube that lets urine out). Botulinum toxin is then injected with a needle in various places in your bladder wall. Usually around 20–30 injections are needed.

As the effects of botulinum toxin wear off over time, the procedure will need to be repeated. How long it lasts can vary between people. Research suggests most people treated for spasticity repeat the injections every 3 to 6 months. For bladder symptoms, most people need to repeat the injections every 5 to 8 months.

As a treatment for MS symptoms, botulinum toxin is only available at specialist centres in the UK. Your GP or consultant neurologist would need to refer you. A spasticity management service would usually offer botulinum toxin injections for muscle stiffness and spasms. A urology team would usually offer them for bladder symptoms.

Botulinum toxin is generally well tolerated and causes few side effects. As it can potentially interact with other medications, it’s important to discuss all of your medicines with your health professionals before treatment.

High doses of botulinum toxin can result in the muscle affected being completely (although not permanently) paralysed. Lower doses may be given to allow some muscle movement to continue. In the case of botulinum toxin injections for bladder incontinence, this can mean you gain more control over bladder leakage.

Side effects of botulinum toxin injections when injected into the bladder include urinary tract infections (UTIs) and difficulty emptying the bladder (called retention). If you struggle to empty your bladder after treatment, you may need to use a catheter. Research suggests that around 3 or 4 in 10 people with MS need to use a catheter following treatment with botulinum toxin. If low-dose botulinum toxin is used, the chance of you needing to use a catheter is lower (by about half).

• Patient Information Leaflet - Botox (EMC website)
• Patient Information Leaflet - Dysport (EMC website)
• Patient Information Leaflet - Xeomin (EMC website)