Standard of Care and Treatment Options for FHM

Because Familial Hemiplegic Migraine (FHM) is so rare, there are no massive randomized controlled trials, and treatment is based on small studies and expert consensus. Treatment is generally divided into two categories: acute treatment (to stop an attack in progress) and preventive treatment (to reduce how often attacks happen) ^[1][2].

Acute Treatment: Stopping an Attack

The goal of acute treatment is to reduce pain and neurological symptoms as quickly as possible. Because FHM involves complex changes in brain blood flow, the medications used differ from those for typical migraines ^[1][3].

Medications to Avoid: The “Red List”

Traditionally, two classes of common migraine medications are contraindicated (advised against) for people with hemiplegic migraine:

• Triptans (e.g., sumatriptan, rizatriptan)
• Ergot Derivatives (e.g., dihydroergotamine)

Why they are avoided: These drugs are vasoconstrictors, meaning they narrow blood vessels to stop a headache ^[4]. During a hemiplegic migraine, the brain’s blood flow is already abnormal, and in some genetic types (like FHM2), the blood vessels may be extra sensitive to these effects ^[5][3]. Doctors avoid these drugs as a precaution to prevent the theoretical risk of a stroke.
It is important to note that this is regulatory labeling and a traditional precaution. Human safety data in FHM are limited, and some headache specialists are beginning to selectively reconsider this rule based on limited safety data ^[4][2]. However, you should never make the decision to use these medications on your own, and no migraine medication should delay emergency assessment of a new stroke-like event.

Preferred Acute Options

For most patients, doctors recommend non-vasoconstricting medications:

• Over-the-counter pain relievers: Such as high-dose NSAIDs (e.g., naproxen) or acetaminophen ^[1]. Always discuss individualized dosing with your doctor due to risks of kidney disease, bleeding, ulcers, or pregnancy, and the risk of medication-overuse headache.
• Anti-nausea medications: These can help with both vomiting and the headache itself.
• Severe Attack Support: In a hospital setting, doctors may selectively use IV fluids, magnesium sulfate, or specific corticosteroids to help calm brain inflammation during a prolonged attack ^[6][7]. These are clinician-directed options, not a universally established protocol.

Preventive Treatment: Reducing Frequency

If your attacks are frequent, severe, or very disabling, your doctor may suggest a daily medication to keep them at bay. These are often used off-label and require specific monitoring:

• Calcium Channel Blockers (Verapamil, Flunarizine): Since FHM is often linked to “calcium gate” malfunctions, these are often considered. Verapamil has long-term observational support for reducing the burden of attacks ^[8][9], but requires cardiac monitoring (like an ECG) to check blood pressure and heart rhythm. Flunarizine is also used widely (though unavailable in some countries), but can cause side effects like tiredness, weight gain, or movement-related changes ^[10].
• Antiepileptics (Topiramate, Valproate, Lamotrigine): These medications help stabilize “irritable” brain cells. Topiramate has shown particular success in small groups of children with FHM ^[11], but requires monitoring for cognitive effects and carries pregnancy risks. Valproate carries major teratogenic (fetal harm) and reproductive risks and is generally avoided in women of childbearing potential. Lamotrigine is often chosen for patients who experience a lot of aura (the vision and sensory changes) ^[12], but carries a risk of serious rash.
• Acetazolamide: This medication is sometimes used, especially in patients who also have symptoms of ataxia (balance issues) ^[8][13]. It may require electrolyte or renal monitoring.

Pregnancy Counseling: Always discuss pregnancy, lactation, and contraception with your neurologist before starting a preventive medication.

Emerging Therapies: The CGRP Revolution

A new class of migraine drugs targets a protein called CGRP, which is involved in transmitting pain. While these were originally tested for “typical” migraines, emerging evidence suggests they may help FHM patients too ^[14].

• Monoclonal Antibodies: Small studies have shown that drugs like galcanezumab or fremanezumab may reduce the number of “aura days” and the severity of attacks for some FHM patients ^[14][15]. However, current evidence for their use in FHM is of very low certainty and largely based on small observational case series.
• A Note of Caution: Some animal studies suggest that another type of CGRP drug (gepants) might be less safe during a stroke-like event, so most experts recommend focusing on the monoclonal antibodies for prevention until more research is done in humans ^[16][4]. Present these therapies as specialist-discussed options.

Because every FHM patient is unique, you may need to try several different medications or combinations before finding the one that works best for your specific genetic profile and symptoms ^[2]. You should keep a written rescue plan documenting your individualized regimen.