What to Know About Ajovy Side Effects

Starting a new medication always comes with questions — especially about side effects. If you've been prescribed Ajovy (Fremanezumab-vfrm) for migraine prevention, here's the good news: most patients tolerate it well, and the most common side effects are mild and temporary.

That said, it's important to know what to watch for. This guide covers the common side effects from FDA labeling, the rare but serious reactions to be aware of, and when you should reach out to your healthcare provider.

What Is Ajovy?

Ajovy is a CGRP inhibitor — a type of monoclonal antibody that blocks calcitonin gene-related peptide (CGRP), a protein involved in migraine attacks. It's FDA-approved for the preventive treatment of migraine in adults and in pediatric patients aged 12 and older weighing at least 45 kg. It's given as a subcutaneous injection either monthly (225 mg) or quarterly (675 mg).

Common Side Effects

The most frequently reported side effects in clinical trials were related to the injection site. These are generally mild and resolve on their own within a few days:

• Injection site pain — The most common complaint. A brief sting or ache at the injection site is normal and usually fades within minutes to hours.
• Injection site redness (erythema) — Some redness around the injection area is common and typically resolves within a day or two.
• Injection site hardening (induration) — A small firm area under the skin at the injection site. This is a normal tissue reaction and usually goes away on its own.
• Injection site swelling — Mild swelling around the injection site may occur and is generally not a cause for concern.

In clinical trials, injection site reactions were reported in approximately 14% of patients taking Ajovy, compared to about 11% taking placebo. The difference is relatively small, which speaks to the medication's overall tolerability.

Less Common Side Effects

Some patients have also reported:

• Mild headache after injection (somewhat ironic, but usually brief)
• Fatigue
• Constipation
• Muscle stiffness or discomfort at injection site

These are not listed as primary side effects in the prescribing information but have been reported by patients. If any of these persist or bother you, mention them to your doctor.

Serious Side Effects

Serious side effects with Ajovy are rare, but they do exist. You should be aware of the following:

Hypersensitivity Reactions

In rare cases, Ajovy can cause allergic reactions, including:

• Anaphylaxis — A severe, potentially life-threatening allergic reaction that can cause difficulty breathing, a drop in blood pressure, and loss of consciousness. This requires immediate emergency medical attention.
• Angioedema — Swelling of the face, lips, tongue, or throat. This can affect your ability to breathe and requires urgent medical care.
• Rash or hives (urticaria) — Widespread rash or raised, itchy welts on the skin.

When to call your doctor or go to the ER: If you experience difficulty breathing, swelling of your face or throat, severe rash, rapid heartbeat, or dizziness after an Ajovy injection, seek emergency medical help immediately. Do not take another dose until you've spoken with your healthcare provider.

Specific Populations

Some groups should take extra care when using Ajovy:

• Pregnancy — Ajovy is not recommended during pregnancy unless the potential benefit justifies the potential risk to the fetus. If you become pregnant while taking Ajovy, contact your doctor right away.
• Breastfeeding — It's not known whether Ajovy passes into breast milk. Discuss the risks and benefits with your doctor if you are breastfeeding or plan to.
• Children under 12 — Ajovy is approved for pediatric patients aged 12 and older weighing at least 45 kg. It has not been studied in younger children.
• Kidney or liver disease — No dosage adjustment is needed for patients with renal or hepatic impairment, according to the prescribing information.

How to Manage Common Side Effects

Most Ajovy side effects are manageable with simple steps:

For Injection Site Reactions

• Rotate injection sites — Alternate between your abdomen, thigh, and upper arm to give each area time to recover.
• Let the medication warm up — Remove Ajovy from the refrigerator 30 minutes before injecting. A room-temperature injection tends to be less painful.
• Apply a cold pack — A cold compress on the injection site for 10 to 15 minutes after injection can reduce pain and swelling.
• Don't rub the site — Gently pressing is fine, but rubbing can increase irritation.

For Fatigue or Other Mild Effects

• Schedule your injection for the evening or before a rest day so any tiredness doesn't interfere with your routine.
• Stay hydrated and get adequate sleep, especially in the 24 hours after injection.

Keeping Track

Consider keeping a simple log of any side effects you experience after each injection, including what happened, how severe it was, and how long it lasted. This information is incredibly useful for your doctor at follow-up appointments and can help determine whether to continue, adjust, or change your treatment.

Ajovy vs. Other CGRP Inhibitors: Side Effect Comparison

If you're weighing Ajovy against other CGRP inhibitors, the side effect profiles are broadly similar:

• Aimovig (Erenumab) — Similar injection site reactions, plus constipation and muscle cramps in some patients.
• Emgality (Galcanezumab) — Similar injection site reactions; loading dose of 240 mg at the start may cause more pronounced site reactions initially.
• Qulipta (Atogepant) — As an oral medication, it avoids injection site reactions entirely but can cause nausea, constipation, and fatigue.

All CGRP inhibitors carry the same rare risk of hypersensitivity reactions. Talk to your doctor about which option has the best overall profile for your situation.

Final Thoughts

Ajovy has a favorable side effect profile for most patients. The most common reactions — injection site pain, redness, and swelling — are mild and temporary. Serious allergic reactions are rare but important to recognize. If you experience any signs of anaphylaxis or angioedema, seek emergency help immediately.

If you're currently taking Ajovy or considering it, the best thing you can do is stay informed and communicate openly with your healthcare provider about any symptoms you notice.

Looking for Ajovy at a pharmacy near you? Check availability on Medfinder.