Botulinum toxin treatment for synkinesis (involuntary facial movement)

This page is for patients considering botulinum toxin injections for involuntary facial movements resulting from abnormal nerve connections (synkinesis).

What is the effect of botulinum toxin?

 Botulinum toxin causes a temporary, partial or complete paralysis (weakness) of the muscle. Botulinum toxin reduces the effect and sensation of involuntaryor abnormal muscle movement (including “twitching“) which may occur with facial nerve palsy.

Will botulinum toxin affect my general health?

The treatment is safe and there is no significant risk of developing botulism or food poisoning. This is because it acts locally at the site of injection with minimal to noabsorption into the blood stream. Although we have never had a patient who experienced any general health problem with botulinum, all medication carries a small potential risk of a serious allergic reaction (anaphylaxis).

There is no known risk when the treatment is given to women who are pregnant or breastfeeding, but some patients prefer to postpone treatment until they have given birth or weaned their child. If you are breastfeeding, we strongly advise that you express your milk to use for 24-48 hours following the injection.

For further information on the use of botulinum toxin in breastfeeding & pregnancy.

What should I expect when I attend the clinic?

First, your vision will be checked and a general health questionnaire will be given by a nurse or healthcare assistant. This is because there are some disorders which may notmake you a good candidate for this treatment. You will then be examined by a specialistdoctor. If the treatment is suitable for you, you will be asked to read and sign a consentform, and will usually receive the treatment on the same day. You should expect to be in the clinic for the whole morning or afternoon.

What is the treatment procedure?

The majority of patients undergo injections without any anaesthetic, as the injection pain is mild. However, you can ask your doctor to apply some skin anaesthetic cream to numb the area before the procedure if you like. You will thentypically have small injections of low-dose botulinum toxin into the abnormally contractingmuscle groups. This is usually very well tolerated and takes less than one minute.

What happens after the injection?

You should be able to go home after the injection. Youmay feel an ache in the injected area after the injection, for which you can take a painkilleras needed. You may develop a small bruise. It is recommended to avoid strenuous physical activity and facial massage for the next day or two to minimise the spread of the toxin to surrounding muscles.

When should I expect to see results from the treatment?

You will usually notice results about two days after the injection.

How long do results last?

This can vary, but results usually last between three and five months.

What are the possible side effects?

Nearly all side effects are temporary and recover with time. Side effects will vary depending on the sites being injected, but may include:

  • Dry eye – this may need to be treated with artificial tear drops before the effect wears off.
  • Drooping of the eyelid on the injected side.
  • Drooping of the corner of the mouth.
  • Temporary double vision – you should not drive while you have double vision. It is veryimportant that you discuss this with the doctor before treatment if this is of particularconcern to you. (see DVLA website: double vision and driving).
  • Slight bruising around the injection site.
  • Drooping of the face on the injected side.

Very rarely, it is possible to get permanent weakness of the facial muscles after botulinum injections.

When do I return to the clinic?

We will make you an appointment to return to the clinic after two weeks to see if the treatment was effective and to consider further treatment if necessary. The dose for your next treatment might be increased or decreased based on the response from your clinician.

Other important information

The majority of medicines used in the UK hold a ‘product licence’ or ‘marketing authorisation’ which is granted by a government organisation. The licence covers specificconditions in which the medicine can be used to treat people. Although botulinum toxin has been used for treating eye conditions at Moorfields since 1982, manufacturers have never applied for a drug productlicence. We use it on a

“named patient” basis, and records are kept of all injections and patient details. This is one ofmany examples of a drug with a product licence for one condition being used safely and successfully for another condition.

If you have any reason to believe that you may be a carrier of hepatitis or HIV virus, pleasemake sure that you tell the nurse or doctor who sees you in the clinic. The information is kept confidential but it is essential that we are informed.

If you are not clear about any part of this treatment or have any questions, please ask the doctor to explain further. 


Authors: Daniel Ezra, consultant, adnexal service and Anna Ginter, adnexal fellow

Review date: April 2020