What side effects does Ajovy (fremanezumab) cause?
Ajovy (fremanezumab) is a calcitonin gene-related peptide (CGRP) monoclonal antibody used to prevent migraine. Common side effects are mostly related to the injection site, because the medicine is given as a subcutaneous shot.
The most typical reported side effects include:
- Injection-site reactions, such as pain, redness, itching, or swelling where the shot is given
- Constipation
- Flu-like symptoms, including fatigue or fever (reported in some patients)
What injection-site reactions are most common?
Patients often notice local effects after dosing. These can include:
- Pain or tenderness at the injection site
- Redness
- Itching
- Swelling
These reactions are usually mild to moderate, occur soon after injection for many patients, and improve on their own.
What serious side effects should you watch for?
With Ajovy, the main serious risk category to watch for is an allergic reaction. Seek urgent medical care if you have signs such as:
- Trouble breathing
- Swelling of the face, lips, tongue, or throat
- Hives or widespread rash
- Dizziness or fainting
If you’ve ever had a serious allergic reaction to fremanezumab or any of its ingredients, you should not take Ajovy and should discuss alternatives with your clinician.
What do people report about long-term or delayed effects?
Because Ajovy is designed to prevent migraine, many patients focus on whether it improves migraine frequency without creating new problems. The side effects that show up most consistently in routine use are injection-site reactions. Delayed or new systemic side effects are not the dominant pattern reported for Ajovy compared with local reactions.
When should you contact a clinician?
Contact your prescriber promptly if:
- Injection-site symptoms are severe, spread, or keep getting worse over time
- You develop symptoms that suggest an allergic reaction
- Constipation or flu-like symptoms become persistent or bothersome
Sources
No source links were provided in your prompt, so I can’t cite specific prescribing-information lines for Ajovy here. If you share the country (US/EU/etc.) or the exact Ajovy prescribing label you’re using, I can map the side effects to that label precisely.