Migraine: AU general practice in the CGRP era

What migraine actually is

Migraine is a primary headache disorder involving complex neurological mechanisms — cortical spreading depression, trigeminovascular activation, calcitonin gene-related peptide (CGRP) release, and central pain sensitisation. About 1 in 7 Australians experience migraine at some point, with a 3:1 female-to-male predominance and prevalence peaking in mid-adult years.

The two main types per the International Headache Society ICHD-3 classification:

• Migraine without aura — most common (~75%). Recurring attacks lasting 4–72 hours, with unilateral or bilateral throbbing pain, moderate to severe intensity, worsened by routine activity, accompanied by nausea/vomiting and/or photophobia/phonophobia.
• Migraine with aura — ~25%. Same attack characteristics but preceded by reversible focal neurological symptoms — typically visual (scintillations, scotomas, zigzags), less commonly sensory, language, or motor.

Chronic migraine = headache on ≥15 days/month, of which ≥8 are migrainous, for ≥3 months. Distinct from episodic migraine in terms of preventive strategy and Medicare-funded biologic access.

A. Core clinical — acute treatment and prevention

Acute treatment

Per Therapeutic Guidelines and AMH, the AU stepwise approach:

Severity	First-line acute
Mild	Paracetamol 1g + NSAID (ibuprofen 400–600 mg, naproxen 500 mg, diclofenac 50 mg) + antiemetic (metoclopramide, prochlorperazine, ondansetron)
Moderate-severe	Triptan (rizatriptan 10 mg, sumatriptan 50–100 mg, eletriptan 40 mg, zolmitriptan 2.5 mg) ± antiemetic
Severe / refractory in office or ED	Subcut sumatriptan 6 mg; IV / IM agents (metoclopramide, prochlorperazine, ketorolac); rarely dihydroergotamine
Status migrainosus (>72 h)	ED — IV fluids, IV antiemetic, IV NSAID, consider corticosteroid burst

Take early. Triptans work much better when taken at the first sign of migraine (early in headache, before central sensitisation). Late dosing reduces efficacy.

Avoid medication-overuse headache. Total reliever use under 10 days/month (counts paracetamol, NSAIDs, triptans, opioids combined). Frequent reliever use paradoxically increases headache frequency.

Gepants (rimegepant, ubrogepant — TGA-approved, PBS Authority for specific criteria) are CGRP-receptor antagonists used acutely; alternative when triptans are contraindicated or poorly tolerated. Lasmiditan (5-HT1F agonist) similar role; CNS sedation profile means no driving for 8h post-dose.

Prevention

Consider preventive therapy if:

• ≥4 migraine days/month with significant disability
• Severe attacks regardless of frequency
• Patient preference
• Medication-overuse pattern emerging
• Specific subtypes (hemiplegic, basilar)

Per eTG and AMH, AU first-line preventives:

• Propranolol 40–240 mg/day (avoid in asthma, depression)
• Amitriptyline 10–50 mg nocte (sedative; also helps comorbid insomnia, tension headache)
• Candesartan 16 mg/day (well-tolerated; less commonly used)
• Topiramate 25–100 mg/day (effective; cognitive side-effects, kidney stones, teratogenic — avoid in pregnancy and women planning pregnancy without strict contraception)

Trial each for at least 8–12 weeks at adequate dose before declaring failure. Three sequential preventives is the typical threshold before specialist escalation.

Second-line / specialist:

• OnabotulinumtoxinA (Botox) — PBS Authority for chronic migraine ≥15 headache days/month, failure of ≥3 prior preventives, neurologist initiation
• CGRP monoclonal antibodies — erenumab, fremanezumab, galcanezumab, eptinezumab; PBS Authority for ≥8 migraine days/month + failure of ≥3 prior preventives, neurologist initiation
• Atogepant (oral CGRP-receptor antagonist) — preventive; PBS criteria similar

The Goadsby NEJM 2017 erenumab trial and Silberstein NEJM 2017 fremanezumab trial anchor the evidence base for the CGRP class.

B. Evidence appraisal — what’s settled and what’s debated

The CGRP era is real. Monoclonal antibodies against CGRP or its receptor reduce monthly migraine days by approximately 1.5–2 more days than placebo in randomised trials — modest in absolute terms, meaningful for patients with frequent attacks. Side-effect profile is favourable compared with older preventives. The class has changed AU specialist headache practice substantially.

Triptans remain first-line for acute moderate-severe attacks. Despite the gepant alternative, triptans are effective, well-tolerated in appropriate patients, and inexpensive. PBS-listed and generic.

Avoid opioids in migraine. They worsen long-term outcomes via medication-overuse headache and don’t address the underlying physiology. Choosing Wisely Australia flags this explicitly.

Vitamin/supplement preventives. Modest evidence for: riboflavin (B2) 400 mg/day, magnesium 400–600 mg/day, coenzyme Q10 100 mg TDS, feverfew. Effect sizes are small but the side-effect profile is benign — reasonable adjunct trial for motivated patients. High-dose B6 (over 50 mg/day sustained) carries neuropathy risk per the TGA 2022 alert — read labels.

Onabotulinumtoxin (Botox). AU PBS-funded for chronic migraine via the PREEMPT protocol (31 injection sites, repeated every 12 weeks). Neurologist-administered.

Devices. Transcranial magnetic stimulation, supraorbital nerve stimulation, occipital nerve blocks — variable evidence, mostly specialist setting.

Lifestyle measures with reasonable trial evidence: consistent sleep schedule, regular aerobic exercise, hydration, structured stress management. Specific dietary triggers vary individually; blanket “migraine diets” don’t outperform identifying and avoiding personal triggers via a headache diary.

C. Australian operations — what the visit looks like

The AU pathway uses standard general practice items:

• Long consultation (items 36 or 44) for new diagnosis, prevention discussion, refractory review
• GPCCMP for chronic migraine with disability — accesses allied-health visits (psychology for CBT, exercise physiology, dietitian where relevant)
• Mental Health Treatment Plan (items 2715 or 2717) — anxiety and depression are bidirectionally linked with migraine
• Imaging is rarely needed in typical migraine — indications for MRI brain: new headache pattern >50, focal neurological deficit, atypical aura features, worst-ever headache, immunosuppression, change in pattern. Indications for CT — exclude haemorrhage in thunderclap-presentation
• Neurology referral — failure of 3 preventives, suspected chronic migraine, biologic consideration, atypical features
• Headache diary — patient-completed; tracks triggers, attack frequency, severity, medication use; informs preventive decisions

(MBS / PBS items verified 2026-05-18 via WebSearch — workspace egress to mbsonline.gov.au + pbs.gov.au still blocked; spot-check confirms current.)

D. Practical patient guidance

A standard migraine consultation covers:

1. History — onset age, frequency, duration, character, location, aura, triggers, comorbidities (anxiety, depression, hypertension, OSA)
2. Diary or self-monitoring for 1–3 months
3. Trigger identification — sleep pattern, hydration, meal timing, alcohol, hormonal correlation
4. Acute regimen — appropriate triptan + NSAID + antiemetic; medication-overuse counselling
5. Preventive consideration — based on frequency and disability
6. Lifestyle plan — sleep, exercise, stress management
7. Mental-health screen — PHQ-9, GAD-7
8. Comorbidity management — BP, OSA assessment if features
9. Red-flag education — when to seek urgent assessment

For pregnancy, breastfeeding, or pregnancy planning: paracetamol acutely (avoid NSAIDs late pregnancy); some triptans have reasonable safety data (sumatriptan most evidence); preventives — most are avoided; specific options under specialist guidance.

When to seek help sooner rather than later

Migraine red flags warranting urgent assessment (call 000 or go to ED):

• “First or worst” headache — sudden severe headache, peak within 1 minute (thunderclap) — exclude subarachnoid haemorrhage
• Headache with fever and neck stiffness — exclude meningitis/encephalitis
• Headache with focal neurological deficit that doesn’t resolve as the headache resolves
• Headache with confusion, seizure, or altered consciousness
• New headache pattern in age over 50 — exclude giant cell arteritis, secondary causes
• Headache worse with cough/exertion/lying down — raised intracranial pressure
• Headache with visual loss (not just aura) — exclude giant cell arteritis (>50), papilloedema
• Headache in pregnancy with hypertension or proteinuria — pre-eclampsia
• Headache in immunocompromise or cancer history — exclude infection or metastases
• Status migrainosus — migraine attack persisting >72 hours despite appropriate acute treatment

What this article is and is not

This is general health information drawn from current Australian general practice guidelines — Therapeutic Guidelines, AMH, NPS MedicineWise, Headache Australia, the Australian and New Zealand Headache Society — and major migraine trials. It is not personal medical advice and does not create a doctor–patient relationship. Decisions about specific acute and preventive treatment are made with your own GP and treating neurologist.

For Australian consumer-friendly sources: Headache Australia, HealthDirect — Migraine, Better Health Channel — Migraine.

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Sources cited

1. RACGP
2. Therapeutic Guidelines (eTG)
3. Australian Medicines Handbook
4. NPS MedicineWise
5. Headache Australia
6. Australian and New Zealand Headache Society
7. RACP
8. TGA
9. HealthDirect — Migraine
10. Better Health Channel — Migraine
11. Choosing Wisely Australia
12. Goadsby PJ et al. — Erenumab (NEJM 2017)
13. Silberstein SD et al. — Fremanezumab (NEJM 2017)
14. International Headache Society — ICHD-3