Calcitonin Gene-Related Peptide (CGRP) monoclonal antibodies
Calcitonin gene-related peptide (CGRP) monoclonal antibodies (mAbs) are a type of preventive medicine for migraine.
About CGRP mAbs
CGRP mAbs were the first medicines specifically designed to prevent migraine attacks. Before this, the only preventive medicines for migraine were ones used for other conditions that had been found to be useful for migraine.
Monoclonal antibodies (mAbs) are proteins made in a laboratory to target specific cells or substances. CGRP mAbs target and block a chemical called calcitonin gene-related peptide (CGRP). CGRP is known to be associated with migraine attacks.
Most CGRP mAbs are administered as injections under the skin, every month or every three months. This is known as a subcutaneous injection. You can do this yourself after being shown how to by a doctor or nurse.
Eptinezumab is given intravenously (into a vein by infusion) once every three months. You’ll have an appointment at hospital to have the infusion.
How CGRP mAbs work
CGRP mAbs work by blocking CGRP. CGRP is released by nerves in your body during a migraine attack. It’s involved in the transmission of pain signals in your nervous system, which contributes to the symptoms of a migraine attack.
CGRP mAbs target and bind to the CGRP protein or its receptor, stopping it from working properly. This can prevent an attack. Taking CGRP mAbs may reduce how many migraine attacks you get, and how severe they are.
CGRP mAbs available in the UK
The following CGRP mAbs are currently approved for use on the NHS in the UK for the prevention of migraine.
- Approved for both episodic and chronic migraine in England, Wales and Northern Ireland. In Scotland, it’s only approved for people with chronic migraine.
- Self-injected at home via subcutaneous injection (injection under the skin) once a month.
- Approved for both episodic and chronic migraine in England, Scotland, Wales and Northern Ireland.
- Self-injected at home via subcutaneous injection (injection under the skin) once a month or every three months.
- Approved for both episodic and chronic migraine in England, Scotland, Wales and Northern Ireland.
- Self-injected at home via subcutaneous injection (injection under the skin) once a month.
- Approved for both episodic and chronic migraine in England, Scotland, Wales and Northern Ireland.
- Administered in hospital as an infusion into a vein every three months.
Episodic migraine is when you have regular attacks, but with headaches on fewer than 15 days a month. Chronic migraine means you have 15 or more days with headache a month, with migraine symptoms on at least eight days, for more than three months.
How to access CGRP mAbs
CGRP mAbs can usually only be prescribed by a headache specialist or consultant neurologist. You will need a referral from your GP. Talk to your GP if you don’t feel that your current migraine medications are working well enough.
Your specialist may recommend a CGRP mAb to help prevent migraine attacks if:
- you are having at least four migraine attacks a month and
- you have tried three or more other preventive medicines at the maximum doses you can tolerate for several months each, and they haven’t worked.
Referral guidelines and access to CGRP can vary depending on where you are in the UK. Your GP can tell you what the situation is like in your area. Your specialist may recommend other medicines you can try too, like gepants.
If you are having difficulties accessing CGRP mAbs even though you’re eligible, speak to your GP or specialist. You can also try contacting the Patient Advice and Liaison Service (PALS) at your hospital.
How well CGRP mAbs work for migraine
CGRP mAbs reduce the number of migraine days for many people with migraine by at least half. This means if you were having eight days with migraine a month, you may have four or less with CGRP mAbs. They appear to be at least as effective as other preventive medicines for migraine. They have been shown to work in some people when other preventive treatments have failed.
Some people respond particularly well to CGRP mAbs. These people are known as ‘super-responders’. They have a reduction in the number of migraine days they get of 75% (three-quarters) or more. Some people may even stop getting migraine attacks altogether.
How long to take CGRP mAbs
If you’re taking a CGRP mAb, your doctor will want to monitor whether they reduce the number of migraine attacks you get. Keeping a headache diary while you take your medicines can help with this.
If your medication is working well, you should be able to continue taking it for at least six months to a year. Your doctor may suggest having a break after this period of time. This is to check whether you still need the medication. This isn’t always necessary.
It’s possible your migraine may restart or become more frequent when you stop treatment. It’s important to discuss with your doctor in advance how to manage this, and when you may be able to restart treatment.
If CGRP mAbs don’t help
CGRP mAbs don’t work for everyone. If they haven’t made a noticeable difference after 12 weeks, your doctor may advise you to stop them.
Your doctor will talk to you about your treatment options. They may suggest trying a different CGRP mAb. Or, they may suggest taking a CGRP mAb in combination with another preventive medicine.
Side effects of CGRP mAbs
CGRP mAbs are generally well tolerated, and side effects are usually mild. The most common side effects of CGRP mAbs include:
- fatigue
- mild injection-site reactions (such as pain, swelling and skin reactions)
- constipation
- itching.
They appear to have fewer side effects than other preventive medicines for migraine. However as they are newer medications, we are still finding out about the side effects they may cause, especially in the longer term.
If you’re concerned about side effects, speak to your specialist or headache nurse. You should also let them know about any other medicines you are taking. CGRP mAbs are unlikely to interact with other medicines, but your doctor or nurse can check this.
People who should not take CGRP mAbs
There hasn’t been enough long-term data yet to say for sure whether CGRP mAbs are safe during pregnancy or breastfeeding. For this reason, your doctor will usually advise you to avoid them during pregnancy, and for at least six months before trying to get pregnant. It’s usually only advised to take them during breastfeeding when there is no other good option.
We have more information on managing migraine in pregnancy.
Your doctor may not recommend treatment with CGRP mAbs if you have had a recent heart attack or stroke, or are at high risk of these conditions. This is because there is not much safety data on this treatment in these groups of people. They may also not recommend CGRP mAbs if you have Raynaud’s syndrome, as there is a chance this medicine can worsen the condition.
Differences between CGRP mAbs and gepants
Gepants are another type of medicine for migraine. Both CGRP mAbs and gepants act on CGRP to prevent migraine, but there are some differences between them.
- Both medicines work by blocking the effect of CGRP, but they do this in a slightly different way.
- CGRP mAbs are administered by injection under the skin or infusion into a vein. Gepants are taken as tablets.
- Both CGRP mAbs and gepants can be used to help prevent migraine attacks. But some gepants can be used as an acute medicine (to treat symptoms of migraine attacks) too.
Last reviewed: November 2024
Next review due: November 2027
Reviewed by: The Migraine Trust Information and Support Services team and Reviewer Panel
If you have feedback on our information, please get in touch at: feedback@migrainetrust.org
References for our information are available on request.
