Migraine

Why Sumatriptan is correct

• The unilateral throbbing headache with nausea and photophobia preceded by a visual aura is migraine with aura; acute abortive therapy is a triptan (5-HT1B/1D agonist), often combined with an NSAID.
• Triptans abort the attack by causing cranial vasoconstriction and inhibiting trigeminal nociceptive transmission.
• Triptans are contraindicated in coronary artery disease, prior stroke or transient ischemic attack, and uncontrolled hypertension because of their vasoconstrictive effect. Product labeling also lists hemiplegic migraine and migraine with brainstem aura (formerly basilar migraine), though that restriction rests on theoretical concern rather than outcome data.

Why the others are wrong

• Topiramate — used for migraine prophylaxis when attacks are frequent, not to abort an acute attack (right-diagnosis-wrong-step).
• Butalbital — a barbiturate in combination analgesics sometimes taken for acute headache, but it is not recommended for migraine: efficacy evidence is poor and it carries a high risk of dependence, withdrawal, and medication-overuse headache (right-step-wrong-drug).
• Propranolol — a migraine prophylactic agent, not an abortive therapy (right-diagnosis-wrong-step).
• Erenumab — a CGRP-pathway drug, which makes it tempting in migraine, but it is a monthly subcutaneous monoclonal antibody used for migraine prevention and does not abort an attack in progress (right-diagnosis-wrong-step).

Why Intravenous metoclopramide is correct

• She meets the ICHD-3 definition of status migrainosus: a debilitating attack typical of her usual migraine except that it has run unremitting for more than 72 hours, now on day 4.
• The bedside screen is reassuring - afebrile, alert and oriented, supple neck, sharp disc margins, normal neurologic examination - so this is an intractable primary headache rather than a secondary one, and the task is to break it pharmacologically.
• Intravenous metoclopramide carries a should-offer (Level B) recommendation for treating the attack in the current American Headache Society emergency department evidence assessment of parenteral pharmacotherapies (2025 update).
• Its abortive effect comes from central dopamine D2 antagonism, not from its gastric prokinetic action, which is why a dopamine antagonist breaks the headache while a pure antiemetic does not. Typical emergency department dosing is 10 mg IV, with some protocols using 20 mg.
• It treats the intractable vomiting at the same time, so one parenteral drug covers both problems in a patient who can no longer keep liquids down and who already has isotonic saline running.
• She took two full oral sumatriptan doses and kept both down without relief, so absorption was not the problem and an oral triptan has genuinely failed; escalation is to a parenteral agent of a different class.

Why the others are wrong

• Intravenous ondansetron - a 5-HT3 antagonist that will settle her nausea and vomiting, which is exactly why it baits here, but it has no established effect on the headache itself and the American Headache Society emergency department guideline makes no recommendation for it. It lacks the central D2 blockade that makes metoclopramide and prochlorperazine abortives rather than merely antiemetics, so the attack would keep running.
• Intravenous hydromorphone - parenteral opioids have no place in this algorithm. The current American Headache Society emergency department guideline assigns intravenous hydromorphone its strongest negative grade, must not offer, and head-to-head trial data show it is inferior to a dopamine antagonist for sustained relief while producing more adverse effects and more return visits. It also adds sedation, blunts serial neurologic assessment, and carries medication-overuse risk in a patient with 15 years of migraine.
• Intravenous dexamethasone - a legitimate part of this visit, but not the agent that aborts the attack. Its established role is a single parenteral dose at or near discharge to reduce recurrence within 72 hours, where it carries a should-offer recommendation; for treating the attack in front of you it rates only may-offer. The lead-in asks what to give now to break the headache, and that is the dopamine antagonist.
• Intravenous diphenhydramine - a fixture of the emergency department migraine cocktail, usually given alongside a dopamine antagonist, which is why it baits; it has no established abortive effect on its own, and the current American Headache Society emergency department guideline grades intravenous diphenhydramine may not offer, so it would add sedation while the attack keeps running

Additional high-yield points

• The parenteral agents the guideline endorses for the attack itself are intravenous prochlorperazine, its single must-offer drug, along with intravenous metoclopramide, subcutaneous sumatriptan, intravenous ketorolac and a greater occipital nerve block. Prochlorperazine is not among these choices; the dopamine antagonists are the emergency department workhorses.
• Switching a failed oral triptan to the subcutaneous route is sound advice in general - subcutaneous sumatriptan bioavailability is roughly 97 percent versus about 14 percent for oral - but it is not the move here: both oral doses stayed down, so the route was never the failure, and by day 4 central sensitization is established and triptans work poorly that late in an attack.
• Akathisia is the adverse effect to warn her about: intense motor restlessness that is easily mistaken for worsening anxiety, and onset can be delayed until after she is home. Do not give diphenhydramine prophylactically to prevent it - a randomized trial found it did not reduce metoclopramide-induced akathisia and only added sedation, and the current guideline grades intravenous diphenhydramine may not offer. Monitor, and treat it if it appears.
• Her baseline of two attacks a month, each breaking within a day, sits below the thresholds for starting preventive therapy and well below the 10-day monthly limit that defines medication-overuse headache, so this visit is about rescue rather than restructuring her regimen.