What Are CGRP Inhibitors and Why Do They Matter?
For decades, people with migraine had to make do with drugs meant for other conditions-antidepressants, blood pressure pills, epilepsy meds. These weren’t designed for migraine. They worked for some, but often came with side effects like brain fog, weight gain, or fatigue. Then, in 2018, everything changed. The first CGRP inhibitors hit the market: drugs made specifically to stop migraine before it starts.
CGRP stands for Calcitonin Gene-Related Peptide. It’s a protein that spikes during a migraine attack, causing inflammation around nerves and widening blood vessels in the brain. This is what triggers the pounding pain, nausea, and sensitivity to light. CGRP inhibitors block this protein or its receptor, cutting off the signal before it escalates. For the first time, migraine prevention wasn’t about borrowing drugs-it was about targeting the root cause.
The Two Types of CGRP Inhibitors: Injections vs. Pills
There are two main kinds of CGRP inhibitors: monoclonal antibodies (mAbs) and gepants. They work differently and are used differently.
Monoclonal antibodies like Aimovig (erenumab), Ajovy (fremanezumab), and Emgality (galcanezumab) are injected under the skin. You get them once a month-or even once every three months. These are strictly for prevention. They don’t help once a migraine is already happening. They work by locking onto either the CGRP protein itself or its receptor, stopping it from activating pain pathways.
Gepants-like Nurtec ODT (rimegepant), Ubrelvy (ubrogepant), and Zavzpret (zavegepant)-are small molecules. They come as pills or nasal sprays. Unlike the injections, some gepants can be used both to stop an attack in progress and to prevent them. Rimegepant, for example, is approved for both acute relief and daily prevention. That’s a game-changer for people who want one tool for both jobs.
How Effective Are They? Real Numbers, Real Results
Let’s cut through the marketing. Do they actually work?
Studies show about half of all users cut their migraine days in half. If you were getting eight migraines a month, you might drop to four or fewer. For people with chronic migraine (15 or more headache days a month), the results are even more dramatic. One study found that 84% of chronic migraine patients had fewer headache days after starting a CGRP inhibitor.
In head-to-head trials, CGRP inhibitors beat older drugs. One study compared erenumab to topiramate, a common preventive. Forty-one percent of people on erenumab cut their migraine days by half or more. Only 24% did on topiramate. And topiramate comes with side effects like tingling, memory issues, and weight loss. Erenumab? Mostly mild injection site reactions.
Real-world data backs this up. On Migraine.com, 78% of users said CGRP inhibitors were "very effective" or "effective." Reddit users report going from 20 migraine days a month down to five. One person wrote: "After 15 years of chronic migraine, Emgality got me down to episodic in three months. Life-changing."
Who Benefits the Most?
CGRP inhibitors aren’t for everyone-but they’re ideal for specific groups.
- Chronic migraine sufferers (15+ headache days/month): These patients often have the most to gain. Many go from chronic to episodic migraine after starting treatment.
- People with medication overuse headache: If you’ve been taking painkillers or triptans too often and your migraines got worse, CGRP inhibitors can break that cycle.
- Those who can’t take triptans: If you have heart disease, high blood pressure, or a history of stroke, triptans are off-limits. CGRP inhibitors don’t constrict blood vessels, so they’re safe here.
- People who failed other preventives: If you’ve tried three or more drugs and nothing worked, CGRP inhibitors still have a 30% success rate.
They’re less helpful if you only get two or three migraines a month. The benefit isn’t as clear, and the cost may not justify it.
Side Effects and Safety: What You Need to Know
These drugs are among the safest migraine treatments ever developed. Most side effects are mild.
For injections: The most common issue is redness or pain at the injection site. About 28% of users report this. It usually fades after a few days. Constipation happens in about 5% of people on erenumab-rare, but worth noting.
For gepants: The big concern is liver enzymes. Rimegepant and ubrogepant can cause mild elevations, so your doctor may check your liver function every few months. This is rare and usually doesn’t cause symptoms. Zavegepant, the nasal spray, can cause a bitter taste or nasal irritation.
No major safety red flags have shown up in five years of use. Unlike older drugs, there’s no risk of dependency, weight gain, or cognitive decline. Even people with heart conditions can use them safely.
Cost and Access: The Biggest Hurdle
Here’s the catch: these drugs are expensive.
Monoclonal antibodies cost $650-$750 a month. Gepants run $800-$1,000. That’s three to five times more than a generic beta-blocker or seizure med.
But here’s the good news: most U.S. insurance plans cover them-with a few steps. You’ll likely need prior authorization. That means your doctor fills out paperwork proving you’ve tried other treatments first. It takes 7-14 days. About 35% of initial requests get denied, but appeals work. Manufacturers offer patient assistance programs that cover up to 80% of out-of-pocket costs for eligible people.
Some people pay $0 after applying. Others pay $25-$50 per month. It’s not free, but it’s often affordable with help.
How to Get Started
If you think CGRP inhibitors might help you:
- Track your migraine days for at least a month. Use an app or a calendar. Count how many days you have moderate to severe pain, nausea, or light/sound sensitivity.
- See a neurologist or headache specialist. Primary care doctors can prescribe them, but specialists know the ins and outs of insurance, dosing, and alternatives.
- Ask about your options. Don’t assume you need an injection. If you prefer pills, ask about rimegepant or ubrogepant.
- Work with the manufacturer’s support team. All four mAb makers (Amgen, Teva, Lilly) and the gepant makers have free patient advocates who help with insurance, co-pays, and injection training.
- Give it time. It can take 2-3 months to see full effects. Don’t quit after one shot.
The Future: What’s Next?
CGRP inhibitors are still evolving.
Researchers are testing nasal sprays and patches to make delivery easier. A new nasal version of erenumab is in phase 2 trials. Pediatric studies are complete-teens as young as 12 may soon be eligible.
Combination therapy is also gaining traction. Some doctors now pair CGRP inhibitors with Botox for chronic migraine patients. One study found 63% of patients responded to the combo-compared to 41% with either alone.
Experts predict CGRP inhibitors will become the new standard of care within five years. Nine out of ten headache specialists believe that. The only question is whether the system can handle the cost long-term.
Final Thoughts: A New Era for Migraine
Before CGRP inhibitors, migraine was treated like a nuisance. Now, it’s treated like the serious neurological condition it is. These drugs don’t just reduce pain-they restore lives. People are going back to work, parenting, traveling, and sleeping through the night.
They’re not perfect. They’re expensive. Injections aren’t for everyone. But for the millions who’ve suffered for years with outdated, ineffective treatments, CGRP inhibitors are the first real hope in decades. And that’s worth celebrating.