The NHS is set to use Botox injections to treat chronic migraines, it has been widely reported today. The muscle-paralysing injections are popular as a cosmetic treatment but, due to its nerve-blocking effects, Botox also has a role in treating certain medical conditions.
The move to use Botox to prevent migraines is based on new guidance published today by the National Institute for Health and Clinical Excellence (NICE), which looks likely to come into force in the near future. NICE recommends that Botox can be considered as an option for the prevention of headaches for people who have chronic migraine (headaches on at least 15 days of every month, at least eight days of which are migraine) that has not responded to at least three prior preventative drug treatments.
This latter point is key – although this treatment will be available on the NHS very few people may actually be eligible. The treatment will be available for people whose migraine is debilitating enough to require preventative treatment to be taken, and then for only the small proportion of those who have not responded to other standard preventative drug options.
What is a migraine?
There are many different types of headache. A migraine is a type of headache where the person often has an intense throbbing headache and additional symptoms such as nausea, vomiting or increased sensitivity to bright light, noise or smell.
There are two recognised forms of migraine. A migraine is often described as a classic migraine with ‘aura’ if the person gets some form of visual distortions prior to the headache. These visual distortions are often in the form of zigzag or flashing patterns across their vision. Non-classic or common migraine does not have this aura.
Migraines are thought to be caused by changes in the chemicals of the brain, in particular serotonin. Serotonin levels are believed to decrease during a migraine, which can cause the blood vessels in the brain to spasm and then dilate, causing the headache. Other triggers can be hormonal changes, certain food items, environmental situations, emotions, stress and physical triggers (for example muscular tension or poor sleep).
Acute migraines are usually treated using painkillers and anti-sickness medications. For people whose migraine does not respond to over-the-counter medications, stronger painkillers may be prescribed by a doctor. If a person suffers from regular debilitating migraines they may need to be prescribed preventative (prophylactic) medications, which they take to stop them getting migraines. There are various drugs currently prescribed for migraine prophylaxis, including beta-blockers and certain antidepressants or anticonvulsants.
What is botulinum toxin type A (Botox)?
Botulinum toxin type A, or Botox as it is commonly known, is a purified neurotoxin (nerve toxin) derived from the bacterium Clostridium botulinum. It works by paralysing the nerve supply to muscles, thereby restricting their movement.
The reasons why Botox might aid migraine are not clear, and several theories have been put forward. At various points it has been suggested that:
- Botox might relax muscles around the head and thereby reduce blood pressure within the brain
- Botox might reduce the nerves’ ability to send pain signals during a migraine
- Botox might prevent the nerves from sending signals that will lead to a migraine
While the mechanism behind any effect is not clear, NICE feels the results of research indicate Botox should be considered as a potential treatment for migraine. Under the new guidelines Botox for the treatment of chronic migraine would be given (to those eligible) by intramuscular injection to between 31 and 39 sites around the head and back of the neck. A new course of treatment can be administered every 12 weeks.
How effective is Botox for migraine?
NICE looked at a systematic review that had identified all randomised controlled trials comparing botulinum toxin type A with placebo for people with chronic headache. Two large trials were identified, and in both of these trials Botox injections reduced the frequency of headache days, which was the main trial outcome that the researchers were interested in. Botox also helped to improve quality of life on validated scales, but was no more effective than placebo in reducing the use of painkillers to treat acute pain.
Is Botox safe for migraine?
In the reviewed trials the most frequently reported adverse reactions in the Botox group were neck pain, headache, migraine, eyelid drooping, muscular stiffness and muscular weakness. Neck pain was the only adverse effect that occurred at a rate of 5% or more in the Botox groups compared with the placebo groups. Other recognised adverse effects of Botox are itching, injection site pain and other muscular effects such as aching, tightness or spasms.
The manufacturer’s summary of product characteristics states that “in general, adverse reactions occur within the first few days following injection and, while generally transient, may have a duration of several months or, in rare cases, longer”.
What does the guideline say?
The guideline says that botulinum toxin type A may be prescribed on the NHS for the prevention of chronic migraine, but only if specific criteria are met. These are as follows:
- The person has chronic migraine, defined as headaches on at least 15 days a month, of which at least eight days are with migraine.
- The person has not responded to at least three drug-based treatments intended to prevent migraines.
- The person is being appropriately managed for medication overuse. The regular use of painkillers to treat headaches can lead to withdrawal headaches as the effect of the painkillers wears off. For some people with chronic headaches this compounds the problem.
If botulinum toxin type A is prescribed, NICE recommends that it should then be stopped if the following criteria are met:
- the person is not adequately responding to treatment (defined as less than a 30% reduction in headache days per month after two treatment cycles)
- the headache has changed from chronic to episodic migraine (defined as fewer than 15 headache days per month) for three consecutive months
What sort of guidance is this?
NICE produces many different types of evidence-based appraisals evaluating the evidence on treatments or interventions for different conditions. Their aim is to ensure that treatments offered are of the highest quality and the best value for money. Rather than being a full guideline that covers all the different ways to manage migraine, the current publication is a ‘technology appraisal’ specifically assessing Botox use for the prevention of headaches in adults with chronic migraine. Technology appraisals evaluate when and how new and existing medicines and treatments should be used in the NHS.
Will Botox definitely be made available?
The current publication is NICE’s final recommendation on the use of botulinum toxin type A for the prevention of headaches in adults with chronic migraine. It is not completely approved as it is currently open to appeal, a process NICE allows with all evaluations. Unless there is later a successful appeal against the decision to approve Botox for migraines, the guidance will be adopted for people with chronic migraine who meet the specific criteria as outlined above.
Analysis by Bazian
Edited by NHS Website
Links to the headlines
Daily Express, 11 May 2012
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Links to the science
Published online May 10 2012