What is botulinum toxin?Botulinum toxin is a protein produced by the bacterium Clostridium botulinum which blocks the release of acetylcholine. Acetylcholine is the substance that is responsible for transmitting electrical impulses which make the facial muscles contract. Various pharmaceutical companies manufacture botulinum toxin for medical and cosmetic use; brand names include BOTOX® and Dysport®.
How does botulinum toxin work?Overactivity of some facial muscles may occur following facial palsy. This can lead to unwanted movements in parts of the face (the medical term is synkinesis). For example, the eye may close when chewing or spontaneous facial twitching can occur. Injecting botulinum toxin into the affected area temporarily paralyses (weakens) the underlying muscles, and hence alleviates symptoms. Injection to the normal side is sometimes used to improve symmetry when the normal (unaffected) side of the face is overactive. See pictures on the right for before and after examples.
Who should you see for botulinum toxin treatment?Your first treatment with botulinum toxin should be carried out by a consultant who specialises in the treatment of facial palsy. Subsequent treatments will be carried out either by the consultant or registrar. In specialist centres, follow-up treatment may be provided by a facial palsy rehabilitation therapist who will have undergone specialist training.
What to think about before your first treatment with botulinum toxin?It is essential to discuss any concerns you may have with your consultant before consenting to treatment. Be aware that the results from botulinum toxin treatment are not guaranteed, and that they may vary with each individual. Make sure that the following has been thoroughly explained to you:
- All foreseeable risks of botulinum toxin therapy (see below) and its potential side effects.
- All contraindications – or the circumstances where botulinum toxin should not be used. (See below.)
- What the treatment is, and what to expect during the procedure: the needle used for injecting is very fine and therefore patients experience very little pain – mostly a little sharpness, which is over almost instantly.
- How you may feel afterwards.
What to expect after your treatment with botulinum toxin?
- You will not feel anything immediately afterwards.
- The initial effects become visible within 48 to 72 hours.
- The maximum effect is reached in about one to two weeks: the area injected will feel more relaxed. You will also notice less unwanted movement in the muscles which have been treated.
- The effect of treatment generally lasts approximately four months, after which further treatment may be required.
- It is very important to carry out any exercises and stretches given to you by your therapist after having your treatment. Having botulinum toxin gives you a window of opportunity to change the way your face moves and to try and separate out movements that have become linked together. It should be used in conjunction with the home exercise programme given to you by your therapist to maximise your recovery.
What are the risks of botulinum toxin treatment?The dosage of botulinum toxin used in this treatment is very small and therefore the risks are minimal. It is generally a safe and effective treatment method. Nevertheless side effects can occur and these usually develop in a few days and may last up to two weeks. It is important to note that sometimes it may take a few weeks for side effects to appear. The potential side effects relate to which area was treated. They can include:
- Bruising or swelling at the site of the injection.
- Slight feeling of nausea or headache.
- Tiredness or pain in the arms and legs.
- Temporary drooping of the eyebrow or upper eyelid.
- Brief visual disturbances (double vision).
- Dry mouth and/or eyes.
- Skin rash or itching.
- Breathing difficulties and/or swallowing difficulties.
- Muscle wasting.
- On rare occasions patients may have an allergic reaction to botulinum toxin injection. This may even occur a few weeks after the injection, and will require immediate medical attention. Symptoms can include swallowing or speech difficulties; wheezing, feeling faint or shortness of breath; hives, and swelling of the face and/or throat.
Is botulinum toxin always safe to use?No. Certain circumstances or preexisting medical conditions means that botulinum toxin is not always appropriate for everyone.
Botulinum toxin treatment is not appropriate if you:
- Are allergic to botulinum toxin or any other ingredients of the injection.
- Have an infection at the proposed site of the injection.
- Are pregnant or breastfeeding.
- Suffer with myasthenia gravis or Lambert-Eaton syndrome.
- Have a blood-clotting disorder.
- Have a needle phobia.
- Have a psychiatric disorder.
- Object to blood donor products, as botulinum toxin contains human serum albumin.
- Have had any problems with injections into your muscles in the past.
- Have inflammation in the muscles or skin area your doctor plans to inject.
- Have significant weakness or wasting of muscles which your doctor plans to inject.
- Have ever suffered from swallowing, breathing disorders or aspiration (inhalation of food or fluids).
- Suffer from any other muscle problems or chronic diseases affecting the muscles.
- Have glaucoma.
- Have had any surgery or injury to your head, neck, legs or chest in the past.
- You are scheduled to have any surgery in the near future.
Frequently asked questions
Last reviewed: 26/01/2015
Next review due: 26/01/2016