CGRP Inhibitors: The New Generation of Migraine Preventive Treatments
If you have frequent migraines, have tried several preventive treatments without success, and are starting to lose hope, this article is for you.
Since 2018, a new class of medications has hit the market: anti-CGRP monoclonal antibodies. It's the first true revolution in migraine prevention since triptans arrived in 1991. For the first time, we have treatments designed specifically for migraine, not borrowed from other conditions (beta-blockers, anti-epileptics, antidepressants).
The clinical trial results are impressive: 50%+ reduction in migraine days for roughly half of patients, with far better tolerability than classic preventive treatments.
This article explains exactly how these medications work, who can benefit, the differences between the 4 available molecules, and the key practical considerations around prescription and insurance access.
What is CGRP?
To understand anti-CGRP medications, you first need to understand what CGRP is.
CGRP (Calcitonin Gene-Related Peptide) is a neuronal peptide present in your nervous system. It has several normal functions, but in migraineurs, it plays a central role in triggering attacks:
- During an attack, your brain's trigeminovascular system releases massive amounts of CGRP
- CGRP causes inflammation of the meninges (the brain's protective membranes) and dilation of blood vessels
- This inflammation and dilation generate the throbbing pain typical of migraine
- CGRP also sensitizes the central nervous system, explaining light sensitivity, sound sensitivity, and nausea
Bottom line: blocking CGRP = blocking the central mechanism of migraine. That's exactly what anti-CGRP medications do.
Our migraine glossary explains all migraine medical terms, including CGRP and the trigeminovascular system.
The 4 anti-CGRP medications available
Four anti-CGRP monoclonal antibodies are FDA-approved and available in the U.S. (and most major markets). All are preventive treatments, not acute treatments.
Erenumab (Aimovig)
First in class, FDA-approved May 17, 2018. Manufacturer: Amgen/Novartis.
- Mechanism: binds to the CGRP receptor (blocking it)
- Administration: subcutaneous self-injection
- Dosage: 70 mg or 140 mg once monthly
- Form: auto-injector pen or pre-filled syringe
Galcanezumab (Emgality)
FDA-approved September 27, 2018. Manufacturer: Eli Lilly.
- Mechanism: binds to the CGRP molecule itself (neutralizing it)
- Administration: subcutaneous self-injection
- Dosage: 240 mg (loading dose), then 120 mg monthly
- Form: auto-injector pen or pre-filled syringe
- Special feature: only CGRP mAb also FDA-approved for episodic cluster headache prevention (June 2019)
Fremanezumab (Ajovy)
FDA-approved September 14, 2018. Manufacturer: Teva.
- Mechanism: binds to the CGRP molecule
- Administration: subcutaneous self-injection
- Dosage options: 225 mg monthly OR 675 mg every 3 months
- Advantage: only anti-CGRP with a quarterly option
- Form: auto-injector pen or pre-filled syringe
Eptinezumab (Vyepti)
FDA-approved February 2020. Manufacturer: Lundbeck.
- Mechanism: binds to the CGRP molecule
- Administration: intravenous infusion (30 minutes)
- Dosage: 100 mg or 300 mg every 3 months
- Particularity: faster onset of action (effective within hours), but requires a clinic visit for infusion
How effective are they really?
Pivotal clinical trials show comparable results across the 4 molecules:
Episodic migraine (fewer than 15 days/month)
- Average reduction: 3 to 4 fewer migraine days per month
- "50% responders" (at least 50% reduction in attacks): 40 to 50% of patients
- "75% super-responders" (at least 75% reduction): 20 to 25%
- Benefit typically visible within the first 4 weeks for most patients
Chronic migraine (15+ days/month)
- Average reduction: 4 to 6 fewer migraine days per month
- 50% responders: 30 to 40% of patients
- Good efficacy even in patients who failed multiple previous preventives
- Reduced acute medication use often observed
Comparison with classic treatments
Anti-CGRP medications are at least as effective as classic preventives (topiramate, propranolol, amitriptyline) with much better tolerability.
Compared to Botox (onabotulinumtoxinA) in chronic migraine, efficacy is comparable but administration is simpler (at-home self-injection vs. multiple injections at the neurologist).
Side effects: an exceptional tolerability profile
This is one of the major advantages of anti-CGRP medications: their side effect profile is close to placebo, unlike classic preventive treatments which are often poorly tolerated.
Common effects (>1 patient in 10)
- Injection site reactions: redness, pain, itching (most frequent and most benign)
Less common effects (1-10%)
- Constipation (especially with erenumab)
- Muscle cramps
- Fatigue
- Allergic reactions (rare but possible)
- Skin itching
Rare but important to know
- Blood pressure elevation (mainly with erenumab, monitor)
- Severe constipation requiring management
- Raynaud's phenomenon (peripheral vasoconstriction)
- Anaphylaxis (very rare)
Long-term safety data
Anti-CGRP medications have been on the market since 2018. The 5+ year safety data is reassuring. No major signal has emerged regarding cardiovascular, oncologic, or immunologic risk.
One residual unknown: the physiological role of CGRP outside of migraine. CGRP plays a role in vascular regulation, and chronic blockade could theoretically have poorly documented consequences in certain populations (heart failure, vascular disease, pregnancy). That's why these treatments are contraindicated during pregnancy.
Who are anti-CGRPs for?
Anti-CGRPs are not indicated for all migraineurs. They're reserved for sufficiently frequent or treatment-resistant migraine.
Eligibility criteria (American Headache Society 2021 consensus)
You're a potential candidate for anti-CGRPs if you meet all of these criteria:
- At least 4 monthly migraine days (some insurance plans require 8+ days)
- Failure of at least 2 preventive treatments from different classes (beta-blocker, topiramate, amitriptyline, etc.) at effective doses for 8+ weeks, OR intolerance/contraindication
- No cardiovascular, hepatic, or allergic contraindication
- Not pregnant or planning pregnancy in the near term
Who CANNOT take anti-CGRPs
- Pregnant or breastfeeding women
- Recent serious cardiovascular events (case-by-case discussion)
- Uncontrolled hypertension
- Known allergy to any component
- Infrequent migraine (<4 days/month) — cost too high for the benefit
What treatment looks like concretely
Step 1: initial consultation
You should consult a neurologist (ideally a headache specialist) to assess eligibility. Bring your migraine diary from the past 3-6 months — it's crucial to demonstrate frequency and previous treatment failures.
Step 2: prescription
If eligible, the neurologist prescribes the anti-CGRP best suited to your profile:
- Anti-receptor (erenumab) or anti-ligand (galcanezumab, fremanezumab, eptinezumab) based on expected tolerability
- Monthly vs quarterly based on your preference
- Subcutaneous vs IV based on practicality
Step 3: learning self-injection (for subcutaneous options)
For subcutaneous injections, you learn to self-inject at home. Auto-injector pens are simple to use (similar to insulin pens). Injection sites: thigh, abdomen, or upper arm.
Step 4: evaluation at 3 months
Standard evaluation criterion: at least 50% reduction in migraine days after 3 months.
- If satisfactory response: continue treatment
- If insufficient response: switch molecule (an anti-receptor after an anti-ligand, for example), or stop
Important: some patients are late responders (response after 6 months rather than 3). The neurologist may extend the trial if the trend is favorable. There's also good evidence that switching between anti-CGRPs works — if one doesn't help, another might.
Step 5: treatment duration
Current recommendations suggest a treatment holiday after 12 to 18 months of effective treatment, to assess whether your migraine profile has shifted. Many patients can then space out or stop without major rebound.
The cost question: insurance and access
List prices
Without insurance, anti-CGRP medications are expensive:
- Erenumab (Aimovig): approximately $650-700/month
- Galcanezumab (Emgality): approximately $700-750/month
- Fremanezumab (Ajovy): approximately $650-700/month
- Eptinezumab (Vyepti): approximately $1,800-2,200 per quarter + infusion costs
How most patients actually pay
In practice, most U.S. patients pay much less through:
- Commercial insurance coverage: most plans cover anti-CGRPs after step therapy (usually requires failure of 2 preventives first)
- Manufacturer copay assistance programs: most major plans → as low as $5/month for commercially insured patients (Aimovig, Emgality, Ajovy all have these programs)
- Patient assistance programs for uninsured or underinsured patients
- Medicare Part D: covers anti-CGRPs but with variable out-of-pocket costs
Always check the manufacturer's official site for the latest copay card terms and eligibility.
International access
Anti-CGRPs are also approved by the EMA (European Medicines Agency) and widely available in the UK, Germany, Italy, Spain, Australia, Canada, and most major markets. Reimbursement policies vary widely — fully or partially covered in many European countries, less consistently in others (notably France in 2026, where these treatments remain non-reimbursed).
Gepants: the oral version of anti-CGRP
Alongside the monoclonal antibodies (injections), another class of anti-CGRP medications exists: gepants. These are small molecules taken orally that block the CGRP receptor.
Three main FDA-approved molecules:
- Rimegepant (Nurtec ODT): can be used for acute attacks (75 mg) AND prevention (75 mg every other day)
- Atogepant (Qulipta): prevention only (10, 30, or 60 mg/day)
- Ubrogepant (Ubrelvy): acute treatment only (50 mg or 100 mg)
Gepants represent the future of the class, offering a more convenient oral option for many patients.
Anti-CGRPs and other treatments
Compatible with triptans
You can continue using your triptans while on anti-CGRP treatment. Many patients find that their triptans become more effective on their rare residual attacks.
Our article on triptans covers their use and possible combinations in detail.
Compatible with other preventives
Anti-CGRPs can be combined with another preventive (a beta-blocker or topiramate, for example) in severe cases. The neurologist decides case by case.
Combination with Botox
For severe chronic migraine, some protocols combine anti-CGRP + Botox. Data is still limited but results are promising.
Track to measure efficacy
To evaluate whether an anti-CGRP is working for you, precise tracking is essential. Without solid data, it's impossible to know if you're at 50% reduction or not, and therefore impossible to make an informed decision about continuing.
Indicators to track before and during treatment:
- Number of migraine days per month (the primary metric)
- Average attack intensity on a 1-10 scale
- Average attack duration
- Number of acute medication doses per month
- Impact on daily life (MIDAS or HIT-6 scale)
- Side effects experienced
You should have 3 months of pre-treatment data (baseline) to compare with 3-6 months of data on treatment.
That's exactly what we built Mellow for: log each attack in seconds, automatically calculate your monthly statistics, and generate a report ready to show your neurologist. When you go to your follow-up to evaluate whether your anti-CGRP is working, you arrive with precise numbers, not vague impressions. It completely changes the quality of the medical decision.
Sources
American Headache Society — Consensus Statement: Update on integrating new migraine treatments into clinical practice. Ailani J, et al. Headache, 2021. headachejournal.onlinelibrary.wiley.com
American Migraine Foundation — Understanding CGRP Treatments. americanmigrainefoundation.org
Association of Migraine Disorders — 15 Frequently Asked Questions About CGRP Monoclonal Antibodies and Gepants. migrainedisorders.org
The Migraine Trust — Migraine preventive treatments: CGRP monoclonal antibodies and Botox. migrainetrust.org
FDA — Aimovig (erenumab-aooe) prescribing information. accessdata.fda.gov
Aditya S, et al. — Advances in CGRP Monoclonal Antibodies as Migraine Therapy: A Narrative Review. PMC, 2023. ncbi.nlm.nih.gov
Edvinsson L, et al. — Calcitonin Gene-Related Peptide (CGRP)-Targeted Monoclonal Antibodies and Antagonists in Migraine: Current Evidence and Rationale. PMC. ncbi.nlm.nih.gov
Mayo Clinic — Migraines: Are they triggered by weather changes? and migraine prevention pages. mayoclinic.org
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