Migraine prevention: what the new guideline changes

AAN/AHS 2026 guideline lowers threshold, elevates CGRP therapies

Guideline · week of 2026-08-31 · Neurology, Internal Medicine · 6 min read · published September 7, 2026

The joint AAN/AHS guideline recommends preventive therapy at ≥4 migraine days per month and positions CGRP monoclonal antibodies alongside traditional oral agents as initial options, without requiring prior treatment failures.

Hibbert Medical · Week of 31 August 2026 · Guideline briefing

> At a glance > What we know — The joint American Academy of Neurology and American Headache Society guideline, published 31 August 2026, recommends offering preventive treatment to adults with ≥4 migraine days per month or disabling attacks, and provides high-confidence evidence that calcitonin gene-related peptide (CGRP) monoclonal antibodies (galcanezumab, erenumab, fremanezumab, eptinezumab) and the gepant atogepant reduce headache frequency in episodic and chronic migraine [1,2,3]. > What we don't know yet — Head-to-head trials comparing CGRP-targeting therapies with traditional oral preventives remain scarce, and evidence comparing active treatments is generally low or very low confidence, restricting conclusions about which agent is most effective for individual patients [3,4]. > What changes Monday — Clinicians should offer preventive therapy at the ≥4 migraine-day threshold, assess treatment response after 8–12 weeks, and consider CGRP monoclonal antibodies and gepants alongside traditional oral agents when selecting initial preventive therapy, guided by patient preference, comorbidities, cost, and formulation [1,2,5].

What happened

On 31 August 2026, the American Academy of Neurology and the American Headache Society published a joint practice guideline update on pharmacologic treatment for migraine prevention in adults, simultaneously in Neurology and Headache [1,2,6]. The guideline supersedes the 2012 AAN/AHS episodic migraine prevention guideline and is endorsed by the American Academy of Family Physicians [1,7]. It is based on a systematic review of randomised controlled trials published through 6 June 2024, which identified 217 eligible studies and applied a modified GRADE process to classify certainty of evidence [3,8].

The guideline states that preventive treatments should be offered to people who experience four or more migraine days per month, four or more moderate to severe headache days per month, or migraine that affects their ability to work or complete daily tasks [1,2]. It includes recommendations on newer preventive treatments approved since 2012, notably CGRP monoclonal antibodies (erenumab, fremanezumab, galcanezumab, eptinezumab), gepants (atogepant, rimegepant), and onabotulinumtoxinA, alongside older oral agents such as propranolol, topiramate, valproate, and amitriptyline [1,2,3,5].

What the evidence actually shows

The systematic review evaluated change in monthly headache days, ≥50% responder rate, and validated quality-of-life measures [3,8]. For episodic migraine, high-confidence evidence showed that galcanezumab and erenumab are more effective than placebo in reducing headache frequency [3,8]. Moderate-confidence evidence supported benefit from atogepant, eptinezumab, fremanezumab, propranolol, topiramate, and valproate [3,8]. This body of evidence is practice-informing for episodic migraine: it confirms that multiple drug classes reduce attack frequency, but the confidence hierarchy and absence of robust head-to-head data mean clinicians must individualise selection based on patient factors, comorbidities, and tolerability rather than relying on a single "best" agent [2,3].

For chronic migraine, high-confidence evidence supported reductions in headache frequency with fremanezumab, galcanezumab, and onabotulinumtoxinA [3,8]. Moderate-confidence evidence supported benefit from atogepant, eptinezumab, erenumab, topiramate, and valproate [3,8]. Across both episodic and chronic migraine populations, erenumab, fremanezumab, galcanezumab, eptinezumab, rimegepant, atogepant, topiramate, and onabotulinumtoxinA demonstrated improvements in patient-reported quality-of-life outcomes on validated instruments [3,8]. This evidence is practice-changing for chronic migraine: the high-confidence findings for CGRP monoclonal antibodies and onabotulinumtoxinA, combined with their migraine-specific mechanisms and superior tolerability profiles, support their use as first-line options in patients with ≥15 headache days per month [2,3,4].

The guideline's treatment of CGRP-targeting therapies reflects a shift from step-therapy gatekeeping. The 2024 American Headache Society position statement, which informed the guideline development, concluded that CGRP-targeting therapies should be considered first-line options for migraine prevention without requiring prior failure of other preventive classes [9]. The evidence for efficacy, tolerability, and safety of these agents was described as substantial and exceeding that for any other preventive approach [9]. This recommendation is practice-changing: it removes the requirement for sequential trials of multiple oral agents before accessing CGRP-pathway therapies, although payer policies may not yet align with this evidence-based stance [5,9].

Evidence comparing active treatments was limited and generally of low or very low confidence, restricting conclusions about comparative effectiveness [3,8]. A 2023 network meta-analysis of 74 trials involving 32,990 patients found high-certainty evidence that CGRP monoclonal antibodies, gepants, and topiramate increase the proportion of patients achieving ≥50% reduction in monthly migraine days compared with placebo, and concluded that CGRP monoclonal antibodies have the best safety and efficacy profile, followed closely by gepants [10]. However, the guideline authors emphasise that the paucity of head-to-head data means clinicians cannot definitively rank agents within or across classes [3,4]. This limitation is not practice-changing in the sense that it does not alter current management, but it underscores the need for shared decision-making when initial therapy is inadequate [2,4].

The guideline specifies that clinicians should assess treatment effectiveness after starting a new medication, with news coverage indicating an 8–12 week evaluation window [1,5]. This recommendation is practice-informing: it formalises an adequate trial duration and discourages premature discontinuation or switching [2,5].

How clinicians are reacting

  • MedPage Today, 31 August 2026 — "New guidance from the American Academy of Neurology (AAN) and the American Headache Society (AHS) aims to help clinicians identify which migraine prevention drugs may be most effective for certain patients" [11].
  • STAT News, 31 August 2026 — Guideline co-author Rebecca Burch stated, "There has been a wealth of new treatment available," and "We know from studies of the U.S. population that many more patients with migraine are eligible" for preventive therapy [12].
  • Neurology Podcast, 2 September 2026 — "Insurance preauthorization restrictions—often limiting approval to those with fewer than 15 headache days per month—can exclude the most difficult-to-treat patients with chronic migraine" [13].

What this changes in practice, and what it doesn't

Clinicians should offer preventive therapy to adults with four or more migraine days per month, four or more moderate to severe headache days per month, or disabling attacks, rather than waiting for higher attack frequencies [1,2]. This threshold formalises eligibility and may expand the population receiving preventive care [1,5]. When selecting a preventive medication, clinicians should discuss the strength of evidence, possible side effects, costs, and formulations (daily oral versus monthly or quarterly injectable) with patients, and consider comorbidities that may favour one agent over another [1,2]. CGRP monoclonal antibodies (erenumab, fremanezumab, galcanezumab, eptinezumab) and the gepant atogepant should be considered alongside traditional oral preventives such as propranolol, topiramate, and amitriptyline as initial options, without requiring prior failure of multiple drug classes [2,9].

Clinicians should assess treatment response after 8–12 weeks [2,5]. If the initial preventive is ineffective or poorly tolerated, switching to a different class is appropriate, as evidence suggests that non-response to one agent does not predict non-response to another [2,4]. For chronic migraine (≥15 headache days per month), high-confidence evidence supports fremanezumab, galcanezumab, and onabotulinumtoxinA [3,8].

What does not change: the guideline does not establish a hierarchy within CGRP-targeting agents or between CGRP therapies and traditional oral preventives, because head-to-head evidence is limited [3,4]. Clinicians cannot yet use biomarkers to predict which patients will respond to which drug [4]. Payer policies may continue to impose step-therapy requirements despite the guideline's evidence-based recommendations [5,13].

For learners

Question 1: A 34-year-old woman with episodic migraine reports six migraine days per month, each lasting 8–12 hours and causing moderate to severe disability. She has no other medical conditions and is not pregnant. According to the 2026 AAN/AHS guideline, which statement about preventive therapy is correct?

A. Preventive therapy should be deferred until she has ≥8 migraine days per month B. She should trial at least two oral preventives before considering a CGRP monoclonal antibody C. Preventive therapy should be offered because she has ≥4 migraine days per month D. Preventive therapy is indicated only if acute medications are ineffective

Answer: C. The guideline recommends offering preventive treatment to patients with ≥4 migraine days per month, ≥4 moderate to severe headache days per month, or disabling attacks [1,2].

Question 2: A 42-year-old man with chronic migraine (18 headache days per month, 12 with migraine features) has tried topiramate and propranolol without benefit. Which preventive therapy has high-confidence evidence for efficacy in chronic migraine?

A. Amitriptyline B. Gabapentin C. Fremanezumab D. Rimegepant

Answer: C. The systematic review found high-confidence evidence that fremanezumab, galcanezumab, and onabotulinumtoxinA reduce headache frequency in chronic migraine [3,8].

Question 3: A 28-year-old woman with episodic migraine asks how long she should continue a newly started preventive medication before deciding whether it is effective. According to the guideline, what is the appropriate evaluation timeframe?

A. 2–4 weeks B. 8–12 weeks C. 6 months D. 12 months

Answer: B. The guideline advises assessing treatment effectiveness after 8–12 weeks, consistent with the duration used in randomised trials [2,5].

References

  1. American Academy of Neurology: Neurology Resources | AAN. aan.com. press-release. https://www.aan.com/PressRoom/Home/PressRelease/5361
  2. Potrebic S, Tanveer S, Becker WJ, et al. Pharmacologic Treatment for Migraine Prevention in Adults Practice Guideline Recommendations: Report of the AAN Guidelines Subcommittee and the American Headache Society. Neurology 2026. doi:10.1212/WNL.0000000000214881. PMID: 42673560. https://pubmed.ncbi.nlm.nih.gov/42673560/
  3. Pringsheim T, Smith DB, Tanveer S, et al. Systematic Review of Pharmacologic Treatment for Migraine Prevention in Adults: Report of the AAN Guidelines Subcommittee and the American Headache Society. Neurology 2026. doi:10.1212/WNL.0000000000218112. PMID: 42673559. https://pubmed.ncbi.nlm.nih.gov/42673559/
  4. Baek Y, Yuan H, Silberstein S. Pharmacotherapy for chronic migraine prevention: a narrative review. Expert opinion on pharmacotherapy 2026. doi:10.1080/14656566.2026.2715707. PMID: 42671197. https://pubmed.ncbi.nlm.nih.gov/42671197/
  5. Updated migraine prevention guidelines reflect new drug options | STAT. statnews.com. news. https://www.statnews.com/2026/08/31/migraine-prevention-medication-guidelines/
  6. Potrebic S, Tanveer S, Becker WJ, et al. Pharmacologic Treatment for Migraine Prevention in Adults Practice Guideline Recommendations: Report of the AAN Guidelines Subcommittee and the American Headache Society. Headache 2026. doi:10.1111/head.70199. PMID: 42673606. https://pubmed.ncbi.nlm.nih.gov/42673606/
  7. Update: Pharmacologic Treatment for Episodic Migraine Prevention in Adults. aan.com. guideline. https://www.aan.com/Guidelines/Home/GuidelineDetail/536
  8. Pringsheim T, Smith DB, Tanveer S, et al. Systematic Review of Pharmacologic Treatment for Migraine Prevention in Adults: Report of the AAN Guidelines Subcommittee and the American Headache Society. Headache 2026. doi:10.1111/head.70200. PMID: 42673583. https://pubmed.ncbi.nlm.nih.gov/42673583/
  9. Charles AC, Digre KB, Goadsby PJ, et al. Calcitonin gene-related peptide-targeting therapies are a first-line option for the prevention of migraine: An American Headache Society position statement update. Headache 2024. doi:10.1111/head.14692. PMID: 38466028. https://pubmed.ncbi.nlm.nih.gov/38466028/
  10. Lampl C, MaassenVanDenBrink A, Deligianni CI, et al. The comparative effectiveness of migraine preventive drugs: a systematic review and network meta-analysis. The journal of headache and pain 2023. doi:10.1186/s10194-023-01594-1. PMID: 37208596. https://pubmed.ncbi.nlm.nih.gov/37208596/
  11. MedPage Today. New Migraine Prevention Guidance Highlights CGRP Drugs, Broad Eligibility. blog, 2026-08-31. https://www.medpagetoday.com/neurology/migraines/122833
  12. STAT News. New guidelines on migraine prevention reflect increasing options for patients. blog, 2026-08-31. https://www.statnews.com/2026/08/31/migraine-prevention-medication-guidelines/?utm_campaign=rss
  13. Neurology Podcast. September 2026 Recall: Updates in Child Neurology. podcast, 2026-09-02. https://neurology.libsyn.com/september-2026-recall-updates-in-child-neurology

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