Injectable CGRP Inhibitors: A New Alternative for Migraine Treatment

Migraine is a type of headache characterized by throbbing pain, often occurring on one side of the head. Some patients may experience nausea, vomiting, and sensitivity to light and sound along with migraine headaches. Migraine headaches can last for several hours or even days and can be severe enough to disrupt daily life, affecting the quality of life of patients.

The exact cause of migraine is not fully understood, but several factors can trigger migraine headaches, such as stress, environmental factors (like bright lights, loud noises, strong odors), or hormonal changes in women.

Migraine headaches cannot be cured completely. Therefore, migraine treatment focuses on preventing migraine attacks and relieving the symptoms. Doctors may consider prescribing preventive medications for migraine headaches in individuals who experience frequent headaches, such as having migraines more than or equal to 4 days per month, those who tend to use pain relievers frequently, or even in those who do not have frequent migraines but the headaches impact their learning, work, and overall quality of life.

Over the years, various medications have been used for migraine prevention and relief such as nonsteroidal anti-inflammatory drugs or NSAIDs, beta-blockers, anticonvulsants, or triptans. However, some patients do not respond well to these medications or have limitations in their use.

Currently, studies have found a relationship between CGRP and migraine headaches, leading to the development of a new class of migraine treatments: injectable CGRP inhibitors. This group of medication effectively prevents migraine headaches and improves the migraine patients’ quality of life.

 

What is CGRP, and how is it related to migraine?

Calcitonin gene-related peptide (CGRP) is a neuropeptide or neurotransmitter found in the brain. This peptide is released from nerve cells, especially in the trigeminal nerve pathway, where it binds to receptors on blood vessels in the brain, as well as receptors on pain-sensing nerve cells. This leads to blood vessel dilation, inflammation, and pain, contributing to migraine headaches. Studies have found that individuals experiencing acute migraine headaches have higher levels of CGRP in their bloodstreams. Therefore, inhibiting the action of CGRP can help alleviate migraine headaches.

 

What are injectable CGRP inhibitors?

Injectable CGRP inhibitors, or CGRP monoclonal antibodies, are biologic medications developed for preventing migraine headaches. These medications work by inhibiting the action of CGRP, either by directly binding to CGRP or its receptors.

Currently, there are at least four types of injectable CGRP inhibitors approved by the Thai Food and Drug Administration for migraine prevention: Erenumab, Galcanezumab, Fremanezumab, and Eptinezumab

 

Who are injectable CGRP inhibitors suitable for?
 

Injectable CGRP inhibitors are suitable for both chronic migraine sufferers (more than 15 headache days per month) and those who experience frequent episodic migraine headaches (8-14 headache days per month). They are also suitable for individuals who have tried other migraine preventive medications without success or have limitations in their use.
 

How are injectable CGRP inhibitors administered?
 

 

Medications	Administration	Frequency
Erenumab	Subcutaneous injection	Once a month
Galcanezumab		Once a month (after the initial loading dose)
Fremanezumab		Once a month or every 3 months depending on the dosage
Eptinezumab	Intravenous injection	Every 3 months

 

Effectiveness of injectable CGRP inhibitors

Studies have shown that injectable CGRP inhibitors significantly reduce the number of migraine headache days per month. Some patients may experience a reduction of more than 50% in headache days per month. Additionally, these medications help reduce the use of pain-relieving medications and improve the quality of life for migraine patients.

For CGRP inhibitor injections administered intravenously, they can provide immediate relief from migraine headaches.
 

Side effects of injectable CGRP inhibitors
 

Common side effects of injectable CGRP inhibitors include itching, pain, or redness at the injection site, upper respiratory tract infections, nausea, and constipation. These side effects are generally mild.
 

Limitations of injectable CGRP inhibitors
 

Since there is limited safety data on the use of injectable CGRP inhibitors in pregnant and lactating women, they should be avoided in these populations. Additionally, caution should be exercised in individuals at risk of cardiovascular diseases, such as heart disease or stroke. Patients should consult with their doctors before using these medications.Top of Form  

If you need further information, you can contact the Drug Information Center at Bumrungrad International Hospital 24 hours a day.