Triptans are a class of medications widely used to treat acute migraine attacks. These drugs, such as sumatriptan and rizatriptan, are highly effective at stopping a migraine once it has begun. However, they carry a serious warning for individuals diagnosed with Coronary Artery Disease (CAD), a condition characterized by the narrowing of the heart’s arteries due to plaque buildup. Because of their interaction with blood vessels, triptans are strictly contraindicated in people with CAD. This prohibition is rooted in the drug’s mechanism of action, which affects the heart’s blood supply.
How Triptans Stop Migraines
Triptans function as agonists, activating specific serotonin receptors in the body, primarily the 5-HT\(_{1B}\) and 5-HT\(_{1D}\) subtypes. During a migraine, the meningeal arteries surrounding the brain become dilated and inflamed. Triptans reverse this by binding to 5-HT\(_{1B}\) receptors on the cranial blood vessel walls, causing them to constrict.
Triptans also activate 5-HT\(_{1D}\) receptors on the trigeminal nerves, inhibiting the release of inflammatory neuropeptides. This combination of cranial vasoconstriction and reduced inflammation directly alleviates the throbbing pain and other symptoms associated with a migraine.
Triptans and Coronary Artery Constriction
The core problem arises because the same 5-HT\(_{1B}\) receptors targeted in the cranial arteries are also found throughout the body’s vascular system, including the coronary arteries. When a triptan is taken, it causes systemic vasoconstriction, meaning it can cause the coronary arteries to narrow. This unintended effect is known as coronary vasospasm, a sudden contraction of the arterial wall. While the effect is generally mild in healthy individuals, the therapeutic effect on migraine vessels is inseparable from the risk of constriction in other blood vessels. This risk of artery narrowing is what forms the basis of the contraindication.
The Clinical Danger in Heart Disease
For a person with Coronary Artery Disease (CAD), drug-induced vasoconstriction dramatically amplifies a pre-existing medical risk. CAD patients already have arteries narrowed by atherosclerotic plaque, which restricts blood flow and leads to myocardial ischemia (insufficient oxygen reaching the heart muscle). When a triptan causes the coronary arteries to constrict further, the reduction in blood flow becomes medically significant and potentially catastrophic. This additional narrowing can immediately trigger angina or provoke a myocardial infarction, commonly known as a heart attack. The medication is strictly prohibited because it can push an already compromised cardiovascular system past its breaking point.
Alternative Migraine Treatments for CAD Patients
People with CAD who suffer from migraines must rely on treatment options that do not cause vasoconstriction.
Acute Treatments
First-line alternatives for acute treatment include non-steroidal anti-inflammatory drugs (NSAIDs) and antiemetics, which address pain and nausea without affecting blood vessel diameter. When simple pain relievers are insufficient, newer acute medications called gepants, such as ubrogepant or rimegepant, are available. These gepants work by blocking the Calcitonin Gene-Related Peptide (CGRP) receptor, a mechanism that does not involve vasoconstriction.
Preventive Treatments
For migraine prevention, several non-vasoconstrictive options are available, including certain beta-blockers, topiramate, and monoclonal antibodies that target CGRP. These preventive CGRP antibodies, such as erenumab or fremanezumab, are a modern treatment that avoids the vascular risks associated with triptans.