Red Flags
- Thunderclap headache, focal neurological deficit, papilloedema, fever, or new headache after age 50 — exclude secondary cause before labelling migraine[1]
- Medication overuse headache (≥10 days/month of triptan/opioid/combination analgesic, or ≥15 days/month of simple analgesic) — withdraw overused agent and start preventive[1]
- Migraine with aura plus combined oral contraceptive — increased ischaemic stroke risk; avoid CHC, use progestogen-only or non-hormonal contraception[1]
- Pregnancy or planning pregnancy on topiramate or valproate — both teratogenic; switch to safer preventive (propranolol, magnesium) and add folate[1]
First-line treatment
Interventions
- Indication for preventive therapy[1]Offer preventive therapy when migraine causes ≥3 days/month of significant disability, ≥4 headache days/month, contraindication or overuse of acute therapy, or chronic migraine (≥15 headache days/month)
- Lifestyle and trigger management[1]Regular sleep, hydration, meals; aerobic exercise 3–5×/week; stress reduction (CBT, mindfulness, biofeedback); identify and modify individual triggers via diary
First-line drug therapy
| Drug | Class | Adult | Paediatric | Notes |
|---|---|---|---|---|
| Propranolol[1] | Non-selective beta-blocker | Start 40 mg PO BD; titrate to 80–240 mg/day in divided doses | Adolescents: 1–4 mg/kg/day in divided doses | Level A evidence; first-line oral preventive especially with comorbid hypertension; avoid in asthma, bradycardia, severe depression |
| Topiramate[1] | Antiseizure (sodium channel + GABA + glutamate) | Start 25 mg PO at night; titrate by 25 mg weekly to 100 mg/day in divided doses; max 200 mg | ≥12 years: 1–3 mg/kg/day | Level A evidence including chronic migraine; avoid in pregnancy, kidney stones, low BMI; cognitive side effects, paraesthesia, weight loss |
| Amitriptyline[1] | Tricyclic antidepressant | Start 10–25 mg PO at night; titrate to 50–75 mg/day | Adolescents: 0.25–1 mg/kg/night | Level B evidence; first choice with comorbid tension-type headache, insomnia, depression, neuropathic pain; sedation, dry mouth, weight gain, urinary retention |
| Candesartan[1] | Angiotensin II receptor antagonist | 16 mg PO once daily; up to 32 mg | — | Level B evidence; well tolerated alternative when beta-blocker contraindicated; useful in hypertension |
| Erenumab / fremanezumab / galcanezumab[1] | Anti-CGRP or anti-CGRP-receptor monoclonal antibody | Erenumab 70–140 mg SC monthly; fremanezumab 225 mg SC monthly or 675 mg quarterly; galcanezumab 240 mg SC loading then 120 mg monthly | — | First-line option per AHS 2024 — no requirement to fail oral preventives first; episodic and chronic migraine; constipation (erenumab) and injection site reactions |
| Atogepant or rimegepant (gepants)[1] | Small-molecule CGRP receptor antagonist | Atogepant 10–60 mg PO once daily for prevention; rimegepant 75 mg PO every other day | — | Oral preventive class; episodic migraine; rimegepant covers both acute and prevention; avoid concurrent strong CYP3A4 inhibitors with atogepant |
| Onabotulinumtoxin A[1] | Neurotoxin, neuromuscular blocker | 155–195 U IM across 31–39 sites every 12 weeks (PREEMPT protocol) | — | Chronic migraine only (≥15 headache days/month); not effective for episodic migraine; specialist administration |
| Magnesium citrate or oxide (adjunctive)[1] | Mineral supplement | 400–600 mg elemental Mg PO daily | — | Adjunctive Level B evidence; well tolerated; diarrhoea is dose-limiting; reasonable in pregnancy |
Propranolol[1]
Non-selective beta-blocker
- Adult
- Start 40 mg PO BD; titrate to 80–240 mg/day in divided doses
- Paediatric
- Adolescents: 1–4 mg/kg/day in divided doses
Level A evidence; first-line oral preventive especially with comorbid hypertension; avoid in asthma, bradycardia, severe depression
Topiramate[1]
Antiseizure (sodium channel + GABA + glutamate)
- Adult
- Start 25 mg PO at night; titrate by 25 mg weekly to 100 mg/day in divided doses; max 200 mg
- Paediatric
- ≥12 years: 1–3 mg/kg/day
Level A evidence including chronic migraine; avoid in pregnancy, kidney stones, low BMI; cognitive side effects, paraesthesia, weight loss
Amitriptyline[1]
Tricyclic antidepressant
- Adult
- Start 10–25 mg PO at night; titrate to 50–75 mg/day
- Paediatric
- Adolescents: 0.25–1 mg/kg/night
Level B evidence; first choice with comorbid tension-type headache, insomnia, depression, neuropathic pain; sedation, dry mouth, weight gain, urinary retention
Candesartan[1]
Angiotensin II receptor antagonist
- Adult
- 16 mg PO once daily; up to 32 mg
- Paediatric
- —
Level B evidence; well tolerated alternative when beta-blocker contraindicated; useful in hypertension
Erenumab / fremanezumab / galcanezumab[1]
Anti-CGRP or anti-CGRP-receptor monoclonal antibody
- Adult
- Erenumab 70–140 mg SC monthly; fremanezumab 225 mg SC monthly or 675 mg quarterly; galcanezumab 240 mg SC loading then 120 mg monthly
- Paediatric
- —
First-line option per AHS 2024 — no requirement to fail oral preventives first; episodic and chronic migraine; constipation (erenumab) and injection site reactions
Atogepant or rimegepant (gepants)[1]
Small-molecule CGRP receptor antagonist
- Adult
- Atogepant 10–60 mg PO once daily for prevention; rimegepant 75 mg PO every other day
- Paediatric
- —
Oral preventive class; episodic migraine; rimegepant covers both acute and prevention; avoid concurrent strong CYP3A4 inhibitors with atogepant
Onabotulinumtoxin A[1]
Neurotoxin, neuromuscular blocker
- Adult
- 155–195 U IM across 31–39 sites every 12 weeks (PREEMPT protocol)
- Paediatric
- —
Chronic migraine only (≥15 headache days/month); not effective for episodic migraine; specialist administration
Magnesium citrate or oxide (adjunctive)[1]
Mineral supplement
- Adult
- 400–600 mg elemental Mg PO daily
- Paediatric
- —
Adjunctive Level B evidence; well tolerated; diarrhoea is dose-limiting; reasonable in pregnancy
Safety-net
- Allow at least 8 weeks of preventive at therapeutic dose before judging effectiveness — earlier abandonment misses real responders[1]
- Track headache days, attack severity, and analgesic use in a diary — gives both you and the clinician objective response data[1]
- If frequency suddenly worsens, attacks change character, or new symptoms appear (vision change, weakness, fever) — same-day medical review[1]
Referral criteria
- Headache with red flag featuresNeurology and brain imaging same-day if acute[1]
- Failure of ≥2 oral preventives at adequate dose and durationHeadache specialist for CGRP-targeted therapy or onabotulinumtoxin A[1]
- Chronic migraine (≥15 days/month) with disabilityHeadache specialist for chronic migraine pathway[1]
- Migraine in pregnancy or breastfeeding requiring preventiveJoint neurology and obstetric clinic[1]
Clinical summary
Indication for and selection of preventive medication in episodic and chronic migraine, including oral first-line agents and CGRP-targeted therapy.