The target is CGRP, a neuropeptide the sensory nerves around your brain release during every attack. It widens vessels and turns up pain signals. Inject CGRP into a migraineur and you trigger an attack; inject it into someone without migraine and nothing happens 1. These drugs block it: four are monthly self-injections, two are pills.
Expect about two fewer migraine days a month than placebo, and a one-in-two shot at halving your monthly count. In the erenumab trial, treated patients dropped 3.7 days versus 1.8 on placebo, with 50% halving their attacks against 27% 2. Galcanezumab and atogepant land in the same range 3 4.
The average looks modest because it pools responders with non-responders. If you respond, your personal drop is closer to half your attacks. The effect holds for years 5.
This is a decision to bring to a neurologist. There is no head-to-head trial, so the pick comes down to delivery, insurance, and your other conditions.
The calendar shifts first. The self-injected drugs usually show within the first month and reach full effect by month three; the pills work inside a few weeks. Where you had ten migraine days you have five, and the ones you still get are often shorter or actually answer a triptan. The dread lifts before the frequency fully does β you start booking the trip you'd have cancelled. Fewer attacks also means fewer "migraine hangover" days lost to fog. It is not a cure: most responders go from frequent to occasional.
The real friction is cost and paperwork. List prices run near $800 a month, but commercial insurance plus a manufacturer copay card brings most patients to near zero. Most plans still require a prior-authorisation form showing four-plus migraine days a month and two failed older preventives; a first denial is the opening move, and a clean appeal usually clears 1. Medicare patients pay specialty-tier prices.
The fine print β when to skip it, and what people get wrong
They don't cure migraine and they aren't Botox. They cut attack frequency; a minority reach near-zero. Botox is a separate drug and many patients use both. "One didn't work so none will" is wrong β switching target recovers response in a real subset.
If it underperforms, look at rescue meds. Years of daily triptans or ibuprofen can add rebound headache that blunts any preventive until you taper off. Stopping the drug after it works lets your attacks drift back to baseline over three to six months.
- 1Charles AC, Digre KB, Goadsby PJ, Robbins MS, Hershey A. (2024). Calcitonin gene-related peptide-targeting therapies are a first-line option for the prevention of migraine: An American Headache Society position statement update. Headache. link
- 2Goadsby PJ, Reuter U, HallstrΓΆm Y, et al. (2017). A Controlled Trial of Erenumab for Episodic Migraine. New England Journal of Medicine. link
- 3Stauffer VL, Dodick DW, Zhang Q, et al. (2018). Evaluation of Galcanezumab for the Prevention of Episodic Migraine: The EVOLVE-1 Randomized Clinical Trial. JAMA Neurology. link
- 4Ailani J, Lipton RB, Goadsby PJ, et al. (2021). Atogepant for the Preventive Treatment of Migraine. New England Journal of Medicine. link
- 5Reuter U, Goadsby PJ, Lanteri-Minet M, et al. (2022). Long-term Efficacy and Safety of Erenumab: Results From 64 Weeks of the LIBERTY Study. Neurology. link
- 6Saely S, Croteau D, Jawidzik L, Brinker A, Kortepeter C. (2021). Hypertension: A new safety risk for patients treated with erenumab. Headache. link
Related in the handbook (4)
- β CGRP inhibitors are the new prevention that halves a typical migraine month β central to women's migraine care.
- β CGRP also widens blood vessels, so blocking it can worsen cold-triggered Raynaud's attacks. Mention it if your fingers go white.
- β CoQ10 is a cheap, low-risk migraine preventive worth trying before or alongside the pricey CGRP drugs.
- β Magnesium is a cheap first-line migraine preventive worth trying before stepping up to CGRP drugs.
CGRP Inhibitors for Migraine Prevention
A monthly self-injection or one pill a day. Once you're past the prior-authorisation paperwork, the regimen itself takes seconds.
Six FDA-approved drugs, more than a dozen large randomised trials, and five years of post-marketing safety data. In 2024 the American Headache Society moved the class to first-line for migraine prevention.
About half of patients on a CGRP drug cut their monthly migraine days in half. For frequent sufferers, that is a major day-to-day quality-of-life shift.
Fewer migraine days and shorter "migraine hangovers" the day after means fewer washed-out days. The effect is indirect β the drug isn't a stimulant.
Migraine wrecks attention and working memory during the attack and for hours after. Fewer attack days means more clear-headed days, not a direct cognitive boost.
Frequent migraine drags mood down through disability and unpredictability. Cutting attack days roughly in half lifts disability and quality-of-life scores along with it.
List price runs roughly $700β$1,150 a month β $8,000β$12,000 a year without insurance. Manufacturer assistance often brings the copay near zero if you have commercial coverage; Medicare patients usually pay more.
Modest knock-on benefit: fewer night and early-morning attacks, less rescue-medication disruption, less dread keeping you up. No direct effect on sleep itself.