What Side Effects Should You Expect With Emgality?

Starting a new medication always comes with questions — and when it involves giving yourself a monthly injection, those questions tend to multiply. If you've been prescribed Emgality (Galcanezumab) for migraine prevention or episodic cluster headache, understanding the potential side effects can help you feel more prepared and less anxious about your treatment.

The good news: most people tolerate Emgality well, and the most common side effects are mild and temporary. But there are a few things you should watch for. Here's what the clinical data and FDA labeling actually say.

What Is Emgality? A Quick Overview

Emgality is a CGRP-blocking monoclonal antibody made by Eli Lilly. It was FDA-approved in September 2018 for migraine prevention and in June 2019 for episodic cluster headache. You inject it once a month under the skin using a prefilled pen or syringe. For a deeper look at how it works, dosing, and more, see our full guide: What Is Emgality?

Common Side Effects

Based on FDA labeling and clinical trial data, the most frequently reported side effects of Emgality include:

• Injection site reactions — This is by far the most common side effect, affecting up to 18% of patients. Reactions can include:
  • Pain at the injection site
  • Redness (erythema)
  • Itching (pruritus)
  • Swelling
• Constipation
• Vertigo (dizziness or a spinning sensation)
• Nasopharyngitis (common cold-like symptoms, runny nose, sore throat)

These side effects are generally mild and tend to improve over time as your body adjusts to the medication. Injection site reactions usually resolve within a few hours to a day.

Serious Side Effects

While rare, there are some serious side effects associated with Emgality that require immediate medical attention:

• Hypersensitivity reactions — Symptoms can include difficulty breathing (dyspnea), hives (urticaria), and rash. These can happen days after an injection.
• Anaphylaxis — A severe, potentially life-threatening allergic reaction. This is rare but possible with any injectable biologic.
• Angioedema — Swelling of the face, lips, tongue, or throat.
• Severe injection site reactions — While most injection site reactions are mild, some patients experience more significant reactions that persist or worsen.

Important: Emgality does not carry a boxed warning (the FDA's most serious warning level). This sets it apart from many other migraine medications.

When to Call Your Doctor

Contact your healthcare provider right away if you experience:

• Difficulty breathing or swallowing
• Swelling of your face, lips, tongue, or throat
• Severe rash or hives
• Dizziness or lightheadedness that doesn't go away
• An injection site reaction that gets worse over several days, spreads, or looks infected

If you experience signs of anaphylaxis (difficulty breathing, rapid heartbeat, severe swelling), call 911 or go to the nearest emergency room immediately.

Side Effects in Specific Populations

Pregnancy

There is limited data on Emgality use during pregnancy. Animal studies did not show harm, but there are no adequate studies in pregnant women. If you are pregnant or planning to become pregnant, talk to your doctor about whether the benefits outweigh the risks.

Breastfeeding

It's unknown whether Galcanezumab passes into breast milk. Discuss with your doctor before using Emgality while breastfeeding.

Children and Teens

Emgality has not been studied in patients under 18 years old. It is not currently approved for pediatric use.

Older Adults

Clinical trials did not show significant differences in side effects for older adults compared to younger patients.

Kidney or Liver Problems

Because Emgality is a monoclonal antibody that is cleared through natural protein breakdown (catabolism) rather than by the kidneys or liver, no dose adjustment is needed for patients with kidney or liver impairment.

How to Manage Common Side Effects

If you're experiencing mild side effects, these tips may help:

For Injection Site Reactions

• Let the pen reach room temperature — Take it out of the refrigerator 30 minutes before injecting. Cold medication stings more.
• Rotate injection sites — Alternate between your abdomen, thigh, and back of the upper arm
• Apply a cold pack after injecting to reduce redness and swelling
• Don't rub the injection site — Gentle pressure is okay

For Constipation

• Increase your water and fiber intake
• Stay physically active
• Talk to your pharmacist about a gentle over-the-counter laxative if needed

For Vertigo

• Move slowly when changing positions (sitting to standing)
• Avoid driving or operating heavy machinery if you feel dizzy after an injection
• Let your doctor know if dizziness is persistent or severe

Most mild side effects improve after the first few months of treatment. If any side effect is significantly affecting your quality of life, talk to your doctor — they may adjust your treatment plan or explore alternative medications.

What About Long-Term Side Effects?

Emgality has been on the market since 2018, giving us several years of real-world safety data. Long-term extension studies have not revealed new safety concerns beyond what was observed in the original clinical trials. The most notable long-term consideration is the development of anti-drug antibodies, which occurs in a small percentage of patients but has not been shown to significantly affect the medication's efficacy or safety.

Final Thoughts

Emgality is generally well-tolerated, with injection site reactions being the most common side effect. Serious allergic reactions are rare but important to recognize. The key is knowing what's normal (mild injection site soreness, occasional constipation) versus what needs medical attention (difficulty breathing, severe swelling, persistent rash).

If you're starting Emgality and want to track your side effects over time, consider keeping a simple log of what you notice after each injection. This gives you and your doctor concrete data to work with at follow-up visits.

Ready to start Emgality? Use Medfinder to find a pharmacy with Emgality in stock near you.