About gepants

Gepants are a type of medicine designed specifically to help treat and prevent migraine. They are also known as CGRP receptor antagonists, as they work by blocking the action of a chemical called CGRP. CGRP stands for calcitonin gene-related peptide. It’s a chemical that’s known to be associated with migraine attacks.

Gepants are the first medicine of this kind that can be taken as tablets, rather than by injection or infusion.

When used to treat migraine attacks, gepants can be a good option for people who can’t take triptan medicines, or don’t tolerate them. Triptans are acute medicines that can help to ease symptoms of a migraine attack. Unlike triptans, you may be able to take gepants if you have previously had a heart attack or stroke, as long as it is at least 6 months after this event.

Gepants also don’t seem to cause medication overuse headache. This can be a problem with triptans and other painkillers if you are using them frequently.

Some gepants are only used to prevent migraine attacks.

How gepants work

Gepants work by blocking calcitonin gene-related peptide (CGRP). CGRP is released by certain nerves in your body during a migraine attack. It’s involved in transmitting pain signals in your nervous system, which, contributes to the symptoms of a migraine attack.

Gepants block the effect of CGRP by binding to CGRP receptors on your nerves. It stops the transmission of pain signals. This stops or prevents a migraine attack.

If you’re taking a gepant to treat migraine attacks (an acute medicine) you take a tablet as soon as an attack starts.  It may help to reduce your pain and other migraine symptoms.

If you are taking gepants as a preventive medicine, you take a tablet every day, or every other day.  They may reduce how many attacks you get, and how severe there are.

Gepants available in the UK

The following gepant medicines are currently approved for use on the NHS in the UK.

Episodic migraine is when you have regular migraines, 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.

There are other gepants in development or that have not yet been approved in the UK. The Migraine Trust will continue to publish updates when new treatments get approved and become available on the NHS.

How to access gepants

For acute treatment (to treat symptoms of a migraine attack)

Your GP should be able to prescribe a gepant medicine to treat symptoms of a migraine attack. But local guidelines may prevent this in some areas. Your GP may need to refer you to a headache specialist or consultant neurologist to prescribe it.

Your doctor may prescribe rimegepant to help with symptoms of migraine attacks if:

• you have tried two different triptans and they didn’t help enough
• you are unable to tolerate the side effects from triptans, and simple painkillers like paracetamol and ibuprofen don’t help
• you can’t take triptans for any reason, such as due to heart problems, and simple painkillers don’t help.

For preventive treatment

Your GP will usually need to refer you to a headache specialist or neurologist in order to access gepants as a preventive treatment. Your doctor may recommend a gepant 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 treatments at the maximum doses you can tolerate for several months each, and they haven’t worked.

Referral guidelines and access to gepants can vary depending on where you are in the UK. Your GP can tell you what the situation is like in your area.

If you are having difficulties accessing gepants, even though you are eligible, speak to your GP or specialist. You can also try contacting the Patient Advice and Liaison Service (PALS) at your hospital.

How well gepants work for migraine

Gepants have been shown to work well in reducing pain and other migraine symptoms during migraine attacks. They are also effective at reducing the number and severity of migraine attacks when you take them daily.

For many people, gepants reduce the number of migraine days they get by more than half.  This means if you were having eight days with migraine a month, you may have four or less with gepants.

They offer an important alternative treatment option for people who don’t respond to other medicines, or who can’t take them.

How long to take gepants

If you take a gepant to prevent migraine, your doctor will want to monitor whether they reduce the number of migraines you get. They may ask you to keep a headache diary while you take your medicines.

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.

It’s possible your migraines may restart or become more frequent when you discontinue 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 gepants don’t help

Gepants don’t work for everyone. If they haven’t made a noticeable difference after 12 weeks, your doctor may advise you to stop them. They will talk to you about your treatment options. They may suggest trying a different preventive medicine, or a combination of preventive medicines.

Side effects of gepants

Gepants are generally well tolerated, and side effects are usually mild. The most common side effects of gepants include:

• fatigue
• nausea
• constipation
• allergic reaction, causing rash and shortness of breath.

Tell your doctor if you experience any of these side effects. As gepants are newer medications, we are still finding out about the side effects they may cause, especially in the longer term.

Interactions

You should also let your doctor know about any other medicines you are taking. Gepants can interact with other medicines, such as antibiotics. This may make them less effective, or more likely to cause side effects. Check with your pharmacist before starting any new medicine while taking a gepant.

Grapefruits and grapefruit juice can also interact with gepants. Eating or drinking large amounts can increase the level of gepants in your body, making side effects more likely. Tell your doctor if you eat grapefruit or drink grapefruit juice while taking gepants. They can advise you whether you need to change your dose.

People who should not take gepants

There hasn’t been enough long-term data yet to say for sure whether gepants are safe during pregnancy or breastfeeding. For this reason, your doctor will usually advise you to avoid them during pregnancy, and for four weeks 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 you take a gepant if you have severe liver or kidney disease.

Differences between gepants and CGRP monoclonal antibodies

CGRP monoclonal antibodies (CGRP mAbs) 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.