What happens in the brain during a migraine? And what medications can be used to treat it?

Migraine can have many different meanings, but it is not ‘just a headache’.

“Migraine” comes from the Greek word “hemicrania”, referring to the common experience that migraine is predominantly one-sided.

Some people experience an “aura” prior to the headache phase, usually a visual or sensory experience that develops over five to 60 minutes. Auras can also involve other domains, such as language, smell, and limb function.

Migraine is a disease with a enormous personal and social impactMost people are unable to function at their normal level during a migraine attack. In addition, the anticipation of the next attack can affect a person’s productivity, relationships, and mental health.

What’s happening in my brain?

The biological basis of migraine is complex and varies depending on the phase of the migraine. Simply put:

The earliest stage is called the prodrome. This is associated with activation of a part of the brain called the hypothalamus, which is thought to contribute to many symptoms such as nausea, changes in appetite, and blurred vision.

The next stage is the aura stage, when a wave of neurochemical changes occurs across the surface of the brain (the cortex) at a rate of 3-4 millimeters per minute. This explains how a person’s aura typically develops over time. People often experience sensory disturbances such as flashes of light or tingling in their face or hands.

In the headache phase, the trigeminal nervous system is activated. This provides sensation to one side of the face, head and upper neck, which leads to the release of proteins such as CGRP (calcitonin gene-related peptide). This causes inflammation and dilation of blood vessels, which is the basis for the severe throbbing pain that accompanies the headache.

Finally, the postdromal phase occurs after the headache has subsided. This often involves changes in mood and energy.

What can you do in case of an acute attack?

A useful way to think about migraine treatment is comparing putting out campfires to forest fires. Medicines are much more successful when applied as soon as possible (the campfire). When the attack is fully developed (in a forest fire), medicines have a much more modest effect.

Aspirin

For people with mild migraines, nonspecific anti-inflammatory medications such as high-dose aspirin or standard-dose nonsteroidal anti-inflammatory drugs (NSAIDs) can be very helpful. Their effectiveness is often enhanced by the use of an anti-nausea medication.

Triptans

For moderate to severe attacks, treatment consists primarily of a class of medications called “triptansThese substances work by reducing the dilation of blood vessels and decreasing the release of inflammatory chemicals.

Triptans vary in route of administration (tablets, tablets, injections, nasal sprays), time to onset of action, and duration of action.

The choice of a triptan depends on many factors, such as whether nausea and vomiting are prominent (consider a soluble wafer or an injection) or how well the patient tolerates it (consider an agent with a slower duration of action).

Because triptans narrow blood vessels, they should be used with caution (or not used) in patients with known heart disease or previous stroke.

Trousers

Some medications that block or modulate the release of CGRP, which are used for migraine prevention (which we discuss in more detail below), also have shown benefit in treating the acute attack. This class of medications is known as the “gepants.”

Gepants are available as injectable proteins (monoclonal antibodies, used to prevent migraines) or as an oral medication (e.g. rimegepant) for acute attacks when a person has not responded adequately to previous attempts with different triptans or is intolerant to them.

They do not cause narrowing of the blood vessels and can be used in patients with heart disease or a previous stroke.

Ditans

Another class of drugs, the “ditants” (for example, lasmiditan), is approved abroad for the acute treatment of migraine. Ditants work by altering a form of serotonin receptor that is involved in the chemical changes in the brain associated with the acute attack.

However, neither the gepants nor the ditans are available through the Pharmaceutical Benefits Scheme (PBS) for the acute attack, so users have to pay out of pocket, at a cost from approximately AUD$300 for eight wafers.

How do you prevent migraines?

The first step is to see if lifestyle changes can reduce the frequency of migraines. This may include improving sleep habits, routine meal schedules, regular exercise, limiting caffeine intake, and avoiding triggers such as stress or alcohol.

Despite these efforts, many people continue to suffer from frequent migraines that cannot be controlled with acute therapies alone. The choice of when to start preventive treatment varies by individual and how willing they are to take medication regularly. Those who suffer from disabling symptoms or experience more than a few migraines per month have the most benefit of initiating preventive measures.

Almost all migraines preventive have existing roles in the treatment of other medical conditions, and the doctor would typically recommend medications that can also help treat pre-existing conditions. First-line preventive measures include:

• tablets that lower blood pressure (candesartan, metoprolol, propranolol),
• antidepressants (amitriptyline, venlafaxine)
• anticonvulsants (sodium valproate, topiramate).

Some people do not have any of these conditions and can safely start with migraine prophylaxis alone.

For all migraine preventive agents, a key principle is to start with a low dose and increase it gradually. This approach makes them more tolerable, and it often takes several weeks or months before an effective dose (usually 2 to 3 times the starting dose) is reached.

It is rare to see immediate noticeable benefits, but over time these medications can lose their effectiveness. usually reduce reduce the frequency of migraines by 50% or more.

‘Nothing works for me!’

For people who did not see an effect from (or could not tolerate) first-line preventive measures, new medicines have been available on the PBS since 2020. These medicines block the action of CGRP.

The most common ones listed on the PBS list anti-CGRP drugs are injectable proteins called monoclonal antibodies (for example galcanezumab and fremanezumab), and are self-administered by monthly injections.

These medications have quickly become a game-changer for people with intractable migraines. The convenience of these injectables contrasts with botulinum toxin injections (also effective and on the PBS list for chronic migraine) which must be administered by a trained specialist.

Up to half of adolescents and a third of young adults are needle phobiaIf this applies to you, hopefully CGRP antagonists in tablet form for migraine prevention are not far away.

Data over the past five years to suggest Anti-CGRP drugs are safe, effective and at least as well tolerated as traditional preventive agents.

However, these are only used after a number of cheaper and more readily available first line treatments (for which there are decades of safety data) have failed, and this is also a criterion for their use under the PBS.

This article has been republished from The conversation under a Creative Commons license. Read the original article.