Emgality side effects and how to avoid them

Common Emgality side effects | Injection site reaction | Serious side effects | Allergic reaction | How long do side effects last? | Warnings | Interactions | How to avoid side effects

In 2018, Emgality (galcanezumab) was approved for migraine prevention, and a year later, the Food and Drug Administration (FDA) added an indication for it to be used for episodic cluster headache relief. It was among the first group of calcitonin gene-related peptide (CGRP) inhibitor drugs to be ushered into use. By blocking the CGRP receptor, this drug class disrupts one cog in the mechanism of migraine.

Brand-name Emgality is still the only member of the class to have indications for two varieties of headache, based on proven efficacy in reducing the number of migraine days per month and improving termination rates of cluster headache episodes. For the treatment of migraine, Emgality is typically reserved for those having four or more migraine attacks per month or for those with chronic migraines. Having been used now for a few years, Emgality has a growing body of evidence regarding both its effectiveness and its adverse reactions.

RELATED: What is Emgality?

Common side effects of Emgality

Side effects of Emgality include:

• Injection site reaction
• Hypersensitivity (allergic) reaction
• Rash
• Urticaria (hives)
• Dyspnea (trouble breathing)

Injection site reaction

Emgality is an injection given subcutaneously (under the skin) once a month when used for migraine headache prophylaxis. In its use for cluster headache relief, the drug is injected once and repeated monthly only if needed to stop the cluster headache episode. The injection is administered via a single-use prefilled syringe or pen device. Clinical trial data has demonstrated that about 18% of Emgality users experience an injection site reaction compared to 13% of placebo (inactive injection) users. These reactions may include pain, redness, or itching.

Of note, redness and itching elsewhere other than the injection site may be a sign of other possible side effects, such as rash or urticaria. Most importantly, one must understand that urticaria, widespread itching, and dyspnea can be part of a more severe hypersensitivity reaction to the medication. Signs of allergic reactions to medications like Emgality can develop rapidly or unfold days after taking the medication. Recognizing early indicators is important in order to get medical assistance in a timely fashion.

Serious side effects of Emgality

• Hypersensitivity reaction
• Anaphylaxis

Hypersensitivity reaction

Hypersensitivity is an allergic reaction and encompasses a broad category of adverse reactions ranging from mild to severe. Relatively mild hypersensitivity events including rash, itching, and urticaria were found to occur in about 4% of Emgality users in one study. The most severe hypersensitivity reaction would be anaphylaxis, which can involve life-threatening breathing difficulty and drops in blood pressure. Anaphylaxis requires immediate medical attention. Similarly, immune-mediated reactions such as these are seen with other monoclonal antibody treatments as well.

How long do Emgality side effects last?

Injection site reactions and hypersensitivity reactions can develop within minutes to hours of an injection. They can potentially last for days to weeks. Treatment of the reactions depends on severity, consisting of simple measures like over-the-counter (OTC) antihistamines or anti-inflammatories for mild reactions or emergency medical treatment for serious allergic reactions. A healthcare provider should be contacted for medical advice to determine what the treatment should be.

Emgality contraindications and warnings

Emgality is not habit-forming and does not elicit any withdrawal symptoms when stopped.

The maximum single dose of Emgality is a 300 mg injection, given in the setting of cluster headache treatment. Any overdose should prompt emergency medical evaluation and a call to the Poison Helpline at 1-800-222-1222.

Anyone with a prior history of a hypersensitivity reaction to Emgality or the CGRP class should not take Emgality. In addition, it is not FDA approved for children. Women who are pregnant or breastfeeding should carefully discuss risks and benefits with their healthcare team, because clinical studies have not adequately assessed the potential for adverse effects in these circumstances.

Emgality interactions

No drug interactions are currently known to exist with Emgality. 

How to avoid Emgality side effects

1. Review your health history and medical conditions with your healthcare professional before taking Emgality, particularly reviewing any history of cardiovascular or blood pressure problems since CGRP has effects on the vasculature (blood vessels). Review your list of other prescription drugs and OTC medications, as well as supplements.
2. Review the prescribed dose carefully. The first dose or loading dose of Emgality for migraine headache prophylaxis is 240 mg, and subsequent monthly doses are 120 mg. However, for cluster headache treatment, the Emgality dose is 300 mg, given as three 100 mg injections, with repeat 300 mg doses monthly only if needed.
3. Follow the instructions for use. Have the prescribing healthcare provider show you how to give your first injection using the prefilled pen device or syringe.
4. Use a proper site for subcutaneous injection. Possible sites to use Emgality include the abdomen (at least 2 inches away from the umbilicus), back of the upper arm, buttock, and front of the mid-thigh (at least 2 inches above the knee cap and at least 2 inches below the groin). Rotate the injection site each time, so as not to use the same site each time.
5. Store the Emgality prefilled pen device in the refrigerator. Place it at room temperature for at least 30 minutes prior to using, but do not leave it at room temperature for more than seven days. Do not microwave, shake, or freeze the device, and do not run it under hot water or leave it in direct sunlight.
6. Use a calendar to keep track of when doses were given and when the next is due. In the event of a missed dose, take the next dose of Emgality as soon as possible.
7. As a relatively new medication, long-term safety data for Emgality is lacking, so continue to discuss your treatment with your healthcare professional at regular intervals.