Which class of migraine medications works as CGRP receptor antagonists and does not cause vasoconstriction?
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Clinical Pharmacology · Neurologic Medications
Migraine Medications
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Migraine drugs fall into two categories with different jobs: abortive (acute) agents stop an attack already underway, while preventive (prophylactic) agents reduce how often and how severely attacks occur. Mild-to-moderate attacks often respond to NSAIDs or acetaminophen combinations, while moderate-to-severe attacks may need triptans, gepants, lasmiditan, or ergotamines. Prevention relies on beta blockers, select antiseizure drugs, tricyclic antidepressants, candesartan, onabotulinumtoxinA, or CGRP monoclonal antibodies. Treating an attack early and avoiding overuse of acute medications are the two safety habits that matter most.
The college version
Abortive (Acute) Therapy
The goal is to relieve pain and associated symptoms once a migraine has begun, and it works best when taken early, while pain is still mild.
NSAIDs and acetaminophen, often paired with caffeine, are first-line for mild-to-moderate attacks, carrying the lowest risk profile of the acute options.
Triptans are 5-HT1B/1D receptor agonists. Activating these receptors constricts dilated cranial blood vessels and inhibits release of vasoactive, pain-promoting neuropeptides from trigeminal nerve fibers, interrupting the migraine pain pathway. Sumatriptan is the prototype; other triptans share this mechanism but differ in onset and duration. Because the mechanism relies on vasoconstriction, triptans are used cautiously or avoided in coronary artery disease, cerebrovascular disease, or uncontrolled hypertension, where vasospasm could provoke ischemia.
Ergotamines act non-selectively on serotonin, dopamine, and adrenergic receptors, producing more potent and longer-lasting vasoconstriction than triptans. Their contraindications are stricter still, including coronary and peripheral vascular disease, uncontrolled hypertension, sepsis, and pregnancy. Ergotamines and triptans should never be combined, since additive vasoconstriction prolongs vasospasm risk.
Gepants, such as ubrogepant and rimegepant, are oral CGRP receptor antagonists. Calcitonin gene-related peptide drives trigeminal pain transmission and vasodilation during an attack; blocking its receptor relieves symptoms without causing vasoconstriction, making gepants useful for patients who cannot safely take triptans or ergotamines because of vascular disease.
Lasmiditan is a selective 5-HT1F receptor agonist. Lacking 5-HT1B activity, it does not constrict blood vessels, but it crosses into the central nervous system and can cause sedation and dizziness, so patients are cautioned against driving or operating machinery after dosing.
Antiemetics such as metoclopramide or prochlorperazine adjunctively treat nausea and vomiting, and their dopamine-blocking action can itself contribute modestly to headache relief.
Preventive (Prophylactic) Therapy
Preventive therapy is taken on a regular schedule, independent of symptoms, to reduce the frequency and severity of future attacks in patients with frequent or disabling migraine.
Beta blockers, particularly propranolol and metoprolol, are first-line preventive agents, thought to work by damping central sympathetic outflow and vascular reactivity. Certain antiseizure medications, including topiramate and valproate, stabilize neuronal excitability and are effective preventive options, though valproate carries teratogenic risk limiting its use in pregnancy-capable patients. Amitriptyline, a tricyclic antidepressant, modulates serotonin and norepinephrine signaling and is especially useful with comorbid insomnia or depression. Candesartan, an angiotensin receptor blocker, is an alternative when beta blockers are not tolerated. OnabotulinumtoxinA is injected into head and neck muscles specifically for chronic migraine, blocking peripheral release of pain-signaling neurotransmitters. CGRP monoclonal antibodies target CGRP or its receptor directly by periodic injection, a newer preventive class acting on the same pathway gepants block acutely.
Medication-Overuse Headache
A central teaching point is that frequent use of abortive medications, including triptans, ergotamines, combination analgesics, and opioids, can paradoxically increase headache frequency, producing a rebound cycle called medication-overuse headache. Patients are counseled to treat attacks early rather than waiting for pain to peak, to limit how often acute medications are used, and to keep a headache diary tracking triggers, attack patterns, and medication use so the prescriber can distinguish acute treatment needs from prevention needs and adjust the regimen.
Special Considerations
Combining a triptan with a serotonergic antidepressant, such as an SSRI or SNRI, carries a caution for serotonin syndrome from additive serotonergic activity; patients should recognize symptoms like agitation, tremor, and autonomic instability. Pregnancy considerations matter broadly here: several preventive agents carry teratogenic risk, so acute and preventive choices are individualized with a prescriber when pregnancy is possible or confirmed.
Eli explains
The same idea, in plain words
Explain it like I’m 10
Think of migraine medicine like dealing with a house fire. Abortive medicines are the firefighters: they show up once the fire (the migraine attack) has started and put it out fast, so calling them early works better than waiting. Triptans and ergotamines work partly by squeezing blood vessels back down, like closing a valve, which is why people with heart or blood vessel problems have to be careful with them. Gepants and lasmiditan are newer helpers that block the pain signal without touching blood vessels at all. Preventive medicines are more like fireproofing the house: you take them every day, whether or not a fire is happening, so fires start less often and burn less badly. Here's the tricky part: calling the firefighters too many times a month can actually make fires start more often. That is why doctors want people to write down when attacks happen and what they take, so they can catch that pattern early.
Check yourself
2 review questions from the chapter. Try each one, then open the answer.
A patient tells the nurse she takes a combination pain reliever almost every day because her headaches "never really go away." What migraine-related concern should the nurse consider, and what teaching point is relevant?
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Concern for medication-overuse headache; teach early treatment and diary use
Taking pain relievers almost daily can actually be causing more headaches rather than fixing them, a pattern called medication-overuse headache. The nurse should teach her to treat attacks early instead of waiting, limit how often she reaches for acute medication, and keep a headache diary so her prescriber can see the pattern and consider adding a preventive medication.
A patient on long-term sertraline for depression is prescribed a triptan for acute migraine attacks. What safety concern should be discussed, and what symptoms would prompt the patient to seek care?
Show answer
Serotonin syndrome risk; watch for agitation, tremor, and autonomic instability
Combining a triptan with an SSRI like sertraline adds two serotonin-boosting effects together, which raises the risk of serotonin syndrome. The patient should be told to seek care if she notices agitation, muscle twitching or tremor, sweating, rapid heart rate, or fever after taking the triptan.
Quick check
3 questions here. Answers stay hidden until you check.
A patient with poorly controlled hypertension and known coronary artery disease needs acute migraine relief. Which class should be used with the most caution due to vasoconstrictive effects?
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Which preventive medication class is injected directly into head and neck muscles and is reserved for chronic migraine?
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