Key takeaways:
Aimovig (erenumab-aooe) is an injectable medication that can help prevent migraines. It’s generally well tolerated but has a few side effects to know about.
Common Aimovig side effects include injection site reactions and constipation. Muscle spasms or cramps may also happen, but these tend to happen less frequently.
Rare but serious Aimovig side effects include severe constipation and high blood pressure. Check with your prescriber or pharmacist if you believe you’re experiencing severe side effects.
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Aimovig (erenumab-aooe) is a prescription medication that can help prevent migraines in adults. It’s available as a once-monthly injection you can give yourself at home. Aimovig may start working within the first month of starting it, and is generally well tolerated. But it does have a few possible side effects to consider.
Aimovig side effects at a glance
Common or mild Aimovig side effects include:
Injection site reactions
Mild constipation
Muscle cramps or spasms
Skin rashes
Rare but serious Aimovig risks include:
Higher blood pressure
Severe constipation
Allergic reactions
Below, we’ll detail four Aimovig side effects you should know about and how to manage them.
Keep in mind: This list doesn’t include all possible side effects. Reach out to your prescriber if you’re concerned about potential side effects while taking Aimovig.
1. Injection site reactions
Injection site reactions are the most common Aimovig side effect. This is when you experience redness, discomfort, and/or swelling around the area where you injected Aimovig. This is a typical and expected side effect of many injectable medications.
Injection site reactions usually go away on their own, typically within a few days. But if you’re looking for ways to ease the discomfort in the meantime, applying warm compresses or ice packs to the affected area may help. Over-the-counter (OTC) pain relievers can lessen the symptoms as well. Examples include acetaminophen (Tylenol) or ibuprofen (Advil, Motrin).
Good to know: Proper injection technique can help minimize injection site reactions. See our guide on how to inject Aimovig for administration tips.
2. Constipation
Constipation is another Aimovig side effect you could experience. But there are several ways to help manage it if it happens:
Increasing the amount of water or fluids you drink per day
Increasing the amount of fiber you consume, either with dietary changes or fiber supplements like Metamucil (psyllium)
Going to the bathroom around the same time each day
Going to the bathroom when you get the urge to go (instead of waiting or putting it off)
If these tips don’t seem to help, ask your prescriber or pharmacist whether you can take OTC medications for constipation, such as laxatives or stool softeners.
Check in with your prescriber if your constipation isn’t improving after a few days. And if it’s severe or gets worse at any point, contact your care team right away. Severe constipation can lead to more serious bowel problems.
Very rarely, severe constipation has been reported by people taking Aimovig. In these cases, people needed hospitalization and surgery to resolve it. This complication most often happens after the first dose of Aimovig, but it can occur after you’ve received a few doses, too. If you take other medications that cause constipation — such as opioids — the risk of this Aimovig side effect may be higher.
Note any changes in your bowel habits when starting Aimovig. And if you develop signs of constipation that can’t be relieved with at-home or OTC remedies, contact your prescriber right away. They may suggest stopping Aimovig and seeking urgent treatment.
3. Muscle cramps or spasms
Muscle cramps and spasms are a less common Aimovig side effect. In general, they appear as uncontrollable muscle movements that are sometimes painful or uncomfortable.
Typically, muscle cramps or spasms with Aimovig should be mild. And they should stop shortly after they start. Stretching or massaging the affected area may help relieve or lessen this Aimovig side effect. Hot showers can also be soothing.
If muscle cramps or spasms are persistent or seem severe, contact your prescriber. More intense muscle cramps aren’t an expected side effect, and there may be another cause for this symptom.
4. High blood pressure
After Aimovig was approved, some people reported that they developed high blood pressure after starting the medication. Clinical trials haven’t been able to say for sure whether this is truly caused by the medication. Typically, people who reported increases in blood pressure had a history of hypertension (chronic high blood pressure) or risk factors for developing hypertension.
Out of caution, the manufacturers of Aimovig warn that high blood pressure may potentially happen. And your risk may be higher if you already have hypertension or other heart problems. If you have a history of these health conditions, ask your prescriber whether you should periodically check your blood pressure at home while receiving Aimovig.
Frequently asked questions
Weight gain isn’t expected with Aimovig, and it wasn’t reported as a side effect in clinical studies. Some other migraine prevention medications — such as propranolol — are more likely to cause weight gain. Others, like topiramate (Topamax), may lead to weight loss.
If you notice an unexpected change in your body weight after starting Aimovig, it’s a good idea to check in with your healthcare team. They can help you look at possible causes, including changes in diet, activity level, or other medications you may be taking.
Hair loss wasn’t reported as a side effect in Aimovig’s initial clinical trials. Since the medication became available, though, some people have shared reports of hair thinning or shedding. However, it’s not clear whether Aimovig was actually the cause.
Keep in mind that stress and migraines itself can sometimes contribute to hair shedding. If you notice new or worsening hair loss, talk with your healthcare team. They can help look for other possible causes and discuss what steps to take next.
Irritability isn’t a common side effect of Aimovig. Still, managing frequent migraines — and adjusting to a new treatment — can affect your mood and stress levels. If you notice increased irritability or other mood changes after starting Aimovig, let your healthcare team know. They can help check for possible causes, such as sleep issues, ongoing pain, or anxiety. Together, you can decide whether to continue Aimovig and whether additional support might help you feel your best.
Weight gain isn’t expected with Aimovig, and it wasn’t reported as a side effect in clinical studies. Some other migraine prevention medications — such as propranolol — are more likely to cause weight gain. Others, like topiramate (Topamax), may lead to weight loss.
If you notice an unexpected change in your body weight after starting Aimovig, it’s a good idea to check in with your healthcare team. They can help you look at possible causes, including changes in diet, activity level, or other medications you may be taking.
Hair loss wasn’t reported as a side effect in Aimovig’s initial clinical trials. Since the medication became available, though, some people have shared reports of hair thinning or shedding. However, it’s not clear whether Aimovig was actually the cause.
Keep in mind that stress and migraines itself can sometimes contribute to hair shedding. If you notice new or worsening hair loss, talk with your healthcare team. They can help look for other possible causes and discuss what steps to take next.
Irritability isn’t a common side effect of Aimovig. Still, managing frequent migraines — and adjusting to a new treatment — can affect your mood and stress levels. If you notice increased irritability or other mood changes after starting Aimovig, let your healthcare team know. They can help check for possible causes, such as sleep issues, ongoing pain, or anxiety. Together, you can decide whether to continue Aimovig and whether additional support might help you feel your best.
The bottom line
Common Aimovig (erenumab-aooe) side effects include injection site reactions and mild constipation. Muscle spasms or cramps may also happen, but these are less common. Serious Aimovig side effects include severe constipation and high blood pressure. Check with your prescriber or pharmacist when starting Aimovig to make sure it’s safe for you.
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References
Amgen. (2025). Aimovig- erenumab-aooe injection. aimovig- erenumab-aooe injection, solution [package insert]. DailyMed.
Bordoni, B., et al. (2025). Muscle cramps. StatPearls.
Dodick, D. W., et al. (2021). Risk of hypertension in erenumab‐treated patients with migraine: Analyses of clinical trial and postmarketing data. Headache.
