Antimigraine Drugs
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Direct answer
Abort the attack, then prevent the next one — migraine therapy is two separate decisions. For attacks: an NSAID with an antiemetic first, a triptan immediately for severe attacks or when the simpler step fails. Triptans are 5-HT1B/1D agonists — 1B constricts dilated cranial vessels, 1D shuts down trigeminal CGRP release — and are contraindicated in coronary disease, uncontrolled hypertension, previous stroke, and hemiplegic or basilar migraine. Ergotamine, the older vasoconstrictor, has narrower margins and dangerous interactions with CYP3A4 inhibitors. Prophylaxis begins at four or more headache days a month: propranolol, topiramate, amitriptyline or flunarizine, with CGRP monoclonal antibodies for refractory cases — all while guarding against medication-overuse headache.
What you must remember
- Triptan pharmacology: sumatriptan 50-100 mg orally (bioavailability only 14 per cent), recurrence in a third of attacks, maximum 200 mg in 24 hours; rizatriptan 10 mg, halved to 5 mg with propranolol.
- Triptan contraindications: ischaemic heart disease, Prinzmetal angina, uncontrolled hypertension, stroke, hemiplegic and basilar migraine, and within 24 hours of ergotamine.
- Ergotamine rules: never with macrolides, azoles or protease inhibitors (CYP3A4 inhibition causing ergotism with limb ischaemia), never in pregnancy or vascular disease; additive danger with triptans.
- Newer acute drugs: gepants (ubrogepant, rimegepant) block CGRP without vasoconstriction — usable in coronary disease; lasmiditan, a 5-HT1F agonist, likewise, with driving barred for eight hours.
- Prophylaxis menu: propranolol (avoid in asthma), topiramate (weight loss, paraesthesia, renal stones, glaucoma, teratogen), amitriptyline (helps comorbid depression and insomnia), valproate (avoid in women who may conceive), flunarizine (sedation, weight gain, depression).
- Thresholds: prophylaxis at four or more headache days monthly; medication-overuse headache with triptans or combinations on 10 or more days, simple analgesics on 15 or more days monthly.
- CGRP antibodies: erenumab, fremanezumab, galcanezumab — monthly or quarterly subcutaneous prophylaxis for refractory migraine.
Building a plan for a young woman with migraine
Start with a diary and a scissor test — what triggers, what precedes. Her acute plan: naproxen with domperidone at onset; if attacks still disable her, sumatriptan at aura onset, repeated once after two hours, switching to rizatriptan wafers when vomiting precludes tablets. She wants prophylaxis because she loses a working day weekly. Asthma strikes propranolol off; she is underweight, so topiramate's appetite suppression argues against; disturbed sleep and low mood argue for amitriptyline 10 mg at night, titrated over weeks. Review at three months by diary, not memory.
Two traps complete the consultation. If she takes a combination analgesic daily, her "transformed migraine" may be medication-overuse headache — the treatment is withdrawal, not a stronger preventive. And if she plans pregnancy, topiramate and valproate leave the list; magnesium supplementation, sleep regularity and low-dose propranolol carry the discussion.
The Indian prescribing pattern
Flunarizine 5-10 mg at night is prescribed in India more than almost anywhere — cheap, once daily, effective — but its depression, weight gain and extrapyramidal ceiling after months of use are under-counselled; the classical exam answer remains propranolol, which is NLEM-listed. Over-the-counter combination analgesics, often with codeine or caffeine, drive much Indian medication-overuse headache; asking exactly what the pharmacy sells the patient is the highest-yield question in the follow-up visit. Gepants and CGRP antibodies remain private-sector options at costs that make the older preventives the public-health answer.
Frequently asked questions
What is the mechanism of triptans in migraine?
5-HT1B agonism constricts dilated cranial vessels while 5-HT1D agonism inhibits trigeminal nerve CGRP release — vasoconstriction plus neurogenic inflammation blockade.
Why are triptans contraindicated in coronary disease?
5-HT1B agonism constricts coronary arteries as readily as cranial ones, risking ischaemia in anyone with established, or probable, coronary artery disease.
When is migraine prophylaxis indicated?
At four or more headache days monthly, or when attacks are disabling despite optimal acute therapy; review each preventive after three months.
Which acute migraine drugs are safe in a patient with coronary disease?
Gepants (rimegepant, ubrogepant) and lasmiditan, which avoid vasoconstriction entirely, or simple analgesia with an antiemetic; triptans and ergotamine are barred.
What defines medication-overuse headache?
Headache on 15 or more days monthly with simple analgesics, or 10 or more with triptans, combinations or opioids, worsening under the very treatment that masks it.