Migraine preventive treatments: CGRP monoclonal antibodies and Botox

By: Ria Bhola, Headache Nurse Specialist

6th April 2023

Who are they for and how to access them?

Calcitonin gene-related peptide (CGRP) monoclonal antibodies (or mAbs) and Botox are two types of treatment currently approved by NICE (National Institute for Health and Care Excellence) and the SMC (Scottish Medicines Consortium). They are injection treatments.

Headache specialist services and some general neurology services will offer these treatments. To understand if they might be suitable for you, you should discuss them with your GP and request a referral to the local headache clinic or neurologist. If you are already seeing a specialist, you should ask whether they may be suitable for you.

CGRP monoclonal antibodies (CGRP mAbs)

There are four CGRP mAbs currently available for migraine prevention. They are erenumab (aimovig), fremanezumab (ajovy), galcanezumab (emgality) and these are self-injected at home. These are used as a single monthly injection (or three injections of ajovy every three months).

A fourth one eptinezumab (vyepti) is given through the vein (intravenous) over half an hour and will require a visit to the hospital to receive it once every three months. They are useful for people with four or more migraine days per month. The main advantages of CGRP mAbs include how quickly they work, the fact they are specifically designed to prevent migraine and that they are generally well tolerated with very few side effects.

Botulinum toxin-A (Botox)

Botox is given in a clinic or hospital as a set of 31 small injections in specific areas on the head and shoulders. They can be repeated once every three months if effective. They are only approved for people with chronic migraine meaning headache on 15 or more days per month, eight of which are migraine days. An advantage of Botox is that the effect of a single treatment can last 12 weeks with minimal side effects. You can find out more about this treatment on our website.

When should you consider these?

There are several reasons you might want to try one of these treatments and a specialist review will be needed. As a reminder, you should see a headache specialist or neurologist:

  • If you have migraine and have not found benefit or adequate benefit with standard treatments you tried with your GP
  • If you feel your symptoms are unusual
  • If your GP thinks your symptoms are not typical for migraine
  • If you have a rare type of migraine
  • If you would like to try a newer, migraine-specific treatment and you meet the criteria outlined below

To be offered one of these treatments, the specialist will review your symptoms and past medicines tried, as well as your general medical history to assess your suitability and whether you meet the NHS criteria (NICE or SMC):

  • You need to have tried three previous preventive medicines. These will often be the tablet options your GP can prescribe such as:
    • a betablocker e.g. propranolol
    • a tricyclic antidepressant e.g. amitriptyline
    • an anti-convulsant e.g. topiramate (valproate for some)
    • candesartan
    • flunarizine
  • An adequate trial is needed – this means taking the treatment in the right doses for an adequate period of time; unless side effects were intolerable, and you had to stop early. (The supplements such as riboflavin, magnesium and coenzyme Q10 and hormonal treatments do not count as a preventive neither does Greater Occipital Nerve blocks, in this context.)
  • You should have a daily headache diary that shows the days you have headache and migraine and when you took a painkiller or triptan.
  • Migraine days refer to the days when your head pain reaches moderate to severe intensity and you also experience symptoms such as light or noise sensitivity, nausea, aura and your symptoms worsen with movement or regular activities. Headache days are less severe and disruptive and often the pain is present without the associated symptoms or features.
  • Botox is only available to people with chronic migraine (headache on at least 15 days per month, eight of which have migraine symptoms).
  • CGRP can be offered to patients with four or more migraine days per month.
  • To continue with either of these treatments, a daily headache diary must continue to assess the degree of benefit and impact of the treatment.

Preventive medicines as ‘repurposed’ treatments

The standard migraine preventive tablet treatments (listed above) and available from your GP, are sometimes referred to as repurposed medicines because they were developed to treat other conditions. For example, propranolol is a betablocker developed to treat high blood pressure but also treats migraine. They are not migraine-specific to target migraine. However, these medicines were found to be effective in migraine and there is good evidence that they work very well to reduce and control migraine for many people. A disadvantage is that many people develop side effects that make it difficult to use, especially at the higher recommended doses.

If you have further questions about your migraine and how to access treatment, do contact us on our free helpline on 0808 802 0066, via this form or via Live Chat at

Find out what to expect during your first Botox appointment here. Read our Q&A about accessing CGRP mAbs here.