Injectable Antispasmodics for Cerebral Palsy

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Injectable Antispasmodics for Cerebral Palsy


Generic NameBrand Name
alcohol "washes" 
botulinum toxinBotox
phenol "washes" 

How It Works

Injectable medicines, like other antispasmodic medicines, relax muscles and reduce muscle spasticity. They act only on the nerves and muscles surrounding the area where they are injected. Doctors give the injections directly into the affected muscle.

Why It Is Used

Injectable medicines help relax tight muscles in the legs or arms affected by cerebral palsy. Injectable medicines may be used:

  • When muscle tightness interferes with daily activities, especially walking.
  • To increase the effectiveness of physiotherapy.
  • To determine whether nerve surgery is appropriate. Doctors often can predict the potential success of surgery by how nerves and muscles react to the injected medicine.

How Well It Works

Botulinum toxin (Botox) works well in children with spastic CP to reduce problems in the lower body (for example, the calf muscle).1 It also can help with problems in the arms and hands.2 More research is needed to find out the overall usefulness and safety of this type of medicine as treatment for cerebral palsy.

These medicines may improve the effectiveness of physiotherapy or delay the need for surgery on the muscles, tendons, and joints. If injectable medicines successfully relax the nerves and muscles, surgical cutting of the nerves may also be helpful.

In most cases, an injectable treatment relaxes tight muscles for a limited time. Alcohol and phenol start to work right away and last about 3 to 6 months. Botox usually begins to take effect within 3 days after injection, although the full effects are often not evident for 1 to 2 weeks. The effects of Botox last for about 4 to 8 months.

Side Effects

All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.

Here are some important things to think about:

  • Usually the benefits of the medicine are more important than any minor side effects.
  • Side effects may go away after you take the medicine for a while.
  • If side effects still bother you and you wonder if you should keep taking the medicine, call your doctor. He or she may be able to lower your dose or change your medicine. Do not suddenly quit taking your medicine unless your doctor tells you to.

Call 911 or other emergency services right away if you or your child has:

  • Trouble breathing, swallowing, or speaking.
  • Hives.
  • Swelling of your face, lips, tongue, or throat.
  • Muscle weakness throughout the body.
  • Problems with your sight or voice.
  • Drooping eyelids.
  • Loss of bladder control.

Call your doctor right away if you or your child has signs of skin infection, such as increased pain, redness, swelling, or fever.

Call your doctor if you or your child has lasting swelling or pain at the injection site.

Common side effects of this medicine include:

  • Pain as the shot (injection) is given or at the site of the shot.
  • Loss of feeling in the area where the shot was given.
  • Rash.
  • Flu-like symptoms, such as nausea or headache.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Botulinum toxin is easier to give and causes less muscle pain than the other injectable medicines. But botulinum toxin costs more than alcohol or phenol.

With an alcohol injection, you'll likely need general anesthesia for the pain.

Taking medicine

Medicine is one of the many tools your doctor has to treat a health problem. Taking medicine as your doctor suggests will improve your health and may prevent future problems. If you don't take your medicines properly, you may be putting your health (and perhaps your life) at risk.

There are many reasons why people have trouble taking their medicine. But in most cases, there is something you can do. For suggestions on how to work around common problems, see the topic Taking Medicines as Prescribed.

Advice for women

If you are pregnant, breast-feeding, or trying to get pregnant, do not use any medicines unless your doctor tells you to. Some medicines can harm your baby. This includes prescription and over-the-counter medicines, vitamins, herbs, and supplements. And make sure that all your doctors know that you are pregnant, breast-feeding, or planning to get pregnant.


Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.



  1. Simpson DM, et al. (2008). Assessment: Botulinum neurotoxin for the treatment of spasticity (an evidence-based review). Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology. Neurology, 70(19): 1707–1714.
  2. Hoare BJ, et al. (2010). Botulinum toxin A as an adjunct to treatment in the management of the upper limb in children with spastic cerebral palsy (Update). Cochrane Database of Systematic Reviews (1).


By Healthwise Staff
Primary Medical Reviewer Susan C. Kim, MD - Pediatrics
Primary Medical Reviewer Brian D. O'Brien, MD - Internal Medicine
Specialist Medical Reviewer Louis Pellegrino, MD - Developmental Pediatrics
Last Revised December 8, 2010

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information.