If migraine is frequent or disabling, preventive treatment aims to reduce how often attacks happen. Standard tablets come first: NICE suggests propranolol, topiramate or amitriptyline. If three preventives have not worked or are unsuitable, specialists can consider newer CGRP medicines (antibody injections or infusions, and tablets called gepants) or Botox injections for chronic migraine.
In trials, CGRP medicines cut migraine days by roughly 1 to 2.5 days a month more than placebo, on average. Some people respond much better than that, and some not at all.
Access differs. In England, NICE recommends all six CGRP medicines after three failed preventives, and five of them for both episodic and chronic migraine. In Ireland, the HSE reimburses the antibody injections only for chronic migraine. For episodic migraine, it reimburses only the two gepant tablets. Nerve-stimulation devices have limited evidence, and NICE allows most of them only with special arrangements or in research.
Not sure your headaches are migraine? Start with our guide to migraine, tension-type and cluster headache.
Prevention is worth discussing with your GP if attacks are frequent or disabling. Two terms matter for funding rules:
Before starting any preventive, doctors check for medication overuse headache. Frequent painkillers or triptans can make headaches more frequent. The HSE treats persistent overuse, especially of codeine or other opioids, as a relative contraindication to CGRP medicines.
A headache diary shows how many migraine days you have, and is how response to treatment is judged.
NICE guideline CG150, last updated in June 2025, says to consider propranolol, topiramate or amitriptyline. The choice depends on your other conditions, preferences and side effect risks. If the first does not work, NICE says to discuss trying a second and then the third.
NICE adds important cautions:
If all three tablets fail, NICE says acupuncture (up to 10 sessions over 5 to 8 weeks) can be considered. The HSE's list of qualifying earlier treatments also includes candesartan, pizotifen, flunarizine, venlafaxine and other beta blockers and tricyclics.
People often ask about supplements. We cover the evidence for magnesium and riboflavin and CoQ10 separately. They are not a substitute for the treatments on this page.
CGRP (calcitonin gene-related peptide) is a signalling molecule involved in migraine pain. The newer medicines block it in one of two ways:
EU dates are from the European Medicines Agency. Routes are from the HSE managed access protocol. US dates are from the FDA's Drugs@FDA database.
The main trials measured change in monthly migraine days. The placebo groups also improved, so the difference between the groups is what matters.
So, compared with placebo, the extra benefit was about 1 to 2.5 fewer migraine days a month, and 0.8 days for rimegepant. Averages hide a wide spread, so funding rules continue treatment only if it works for you.
NICE and the HSE use the same thresholds. NICE checks at 12 weeks. Treatment should continue only if migraine frequency has fallen by:
According to the UK product information for erenumab, injection site reactions and constipation are among the common side effects. Constipation is usually mild and often settles within three months, but serious complications have been reported.
US labels for the antibodies and gepants warn about hypersensitivity reactions, new or worsening high blood pressure and Raynaud's phenomenon, according to the FDA. The antibody labels also warn about serious constipation.
There is limited pregnancy data. The UK erenumab information says it is preferable to avoid it during pregnancy as a precaution. Tell your specialist if you are planning a pregnancy.
Botulinum toxin type A (Botox) is given as a series of small injections around the head and neck every 12 weeks, in a specialist clinic. It is licensed in the UK for preventing headaches in adults with chronic migraine, according to its UK product information.
NICE TA260 recommends it for chronic migraine after three preventive medicines have failed, once medication overuse has been managed. It should be stopped if headache days fall by less than 30% after two treatment cycles. It should also stop if migraine has become episodic for 3 months in a row.
The evidence comes from two trials called PREEMPT. Pooled, they included 1,384 adults. At 24 weeks, headache days fell by 8.4 with Botox and 6.6 with placebo, a difference of about 2 days (Dodick 2010). But the first trial missed its main goal. It found no difference in headache episodes (−5.2 versus −5.3), though headache days and migraine days did improve (Aurora 2010).
In Ireland, the HSE counts two cycles of Botox, 12 weeks apart, as an adequate trial of one preventive.
These devices stimulate nerves or the brain to reduce pain signals. NICE has assessed several, cautiously.
"Special arrangements" means the procedure can be used, but with extra consent, governance and audit, because the evidence is uncertain. NICE notes that the devices in its occipital nerve stimulation evidence base lost their CE marks for this use in January 2020.
In the US, the FDA has cleared several migraine devices, including Cefaly (2014) and Nerivio (2019), according to its 510(k) and De Novo records. We did not confirm CE or UKCA marks for individual devices. We found no HSE funding decision on any of them.
The HSE reimburses CGRP medicines through a managed access protocol (version 2.1, May 2026). The main rules are:
The High Tech Arrangement means a hospital consultant prescribes and the medicine is dispensed through community pharmacies. Combining two CGRP medicines is not reimbursed.
NICE recommends all six medicines, each in its own technology appraisal. For erenumab, galcanezumab, fremanezumab, eptinezumab and atogepant, the rule is at least 4 migraine days a month after three failed preventives. That covers both episodic and chronic migraine. Erenumab is recommended only at the 140 mg dose.
Rimegepant is recommended for episodic migraine only (4 to 14 attacks a month) after three failed preventives. Where several options suit, NICE says to use the least expensive.
The Scottish Medicines Consortium differs on one point. It accepted erenumab only for chronic migraine. It accepted fremanezumab, galcanezumab, eptinezumab and atogepant for both episodic and chronic migraine, and rimegepant for episodic migraine, each after three failed preventives.
We have not listed trials. Ask your neurologist if you are interested in research.
Most people start with their GP. If standard preventives have not helped, ask about referral to a neurologist or headache clinic. Our guide to getting referred to a neurologist in Ireland explains the routes.
Bring your diary and a list of every preventive you have tried, for how long, and why you stopped. In Ireland, the neurologist needs that history to apply for funding.
The NHS says to call for emergency help if a headache starts suddenly and is extremely painful, or comes with weakness, numbness, confusion, a seizure, loss of vision, or a very high temperature and stiff neck. In Ireland or the UK, call 112 or 999.
In Ireland, HSE-funded CGRP medicines are prescribed by approved consultant neurologists and their teams, not GPs. In England, local NHS arrangements decide who prescribes.
The HSE protocol reimburses the four antibodies only for chronic migraine. For episodic migraine, it reimburses atogepant and rimegepant tablets, after three failed preventives. NICE in England recommends the antibodies for both.
NICE judges response at 12 weeks. For Botox, NICE assesses response after two treatment cycles.
This article is general information, not medical advice. Talk to your GP or neurologist about your own situation.
Reviewed by: Proco Team
Last updated: November 2026