CGRP Preventive Therapies — What They Are, Who Qualifies, and How to Get Them Approved
CGRP-targeted preventives require documented failure of two oral preventive classes — here is what payers actually look for.
PA impact: This card directly affects prior authorization outcomes. Documentation language from this card can be used in PA letters and appeals.
What CGRP-targeted preventives are and why they matter. Two classes of preventive migraine medication now target the CGRP pathway: monoclonal antibodies (mAbs) and gepants. Both were developed specifically for migraine rather than borrowed from other indications, and both carry Level A evidence for migraine prevention. mAbs (erenumab, fremanezumab, galcanezumab, eptinezumab) are injectable and work by blocking CGRP or its receptor. Gepant preventives (atogepant, rimegepant) are oral and competitively block the CGRP receptor. Both classes have FDA approval for both episodic and chronic migraine prevention.
Who qualifies. Most payers require four or more migraine days per month and documented failure of two oral preventive medication classes. The two-class standard typically means two of: beta-blockers, anticonvulsants (topiramate, valproate), tricyclic antidepressants, or SNRIs. Some payers accept one class if the reason for stopping was a serious adverse event. Each prior trial must be documented with the four critical elements: agent, dose achieved, duration, and reason for discontinuation (Card 4).
Contraindications that bypass step therapy. Teratogenicity concerns with topiramate and valproate bypass those classes for women of childbearing age — document the reproductive risk explicitly, not just the drug name (see .vaultterato in the Smart Phrase Library for the documentation template). Cardiovascular contraindications to beta-blockers (bradycardia, heart block, hypotension) bypass that class. Cognitive impairment concerns with topiramate in patients whose occupation depends on cognitive function may be accepted as a documented contraindication by some payers.
The ICD-10 code must match the indication. Episodic migraine codes (G43.0xx, G43.1xx) and chronic migraine codes (G43.7xx) are both valid — all approved CGRP preventives cover both. Unspecified headache (R51.9) causes automatic denial. Code the predominant presentation. The Vault validates ICD-10 codes against payer requirements at time of search.
Preferred agent and cost. Payer formulary placement is driven by rebate contracts, not clinical differentiation. Check formulary tier before prescribing — the Vault identifies the preferred agent for the patient's specific payer at time of search. Even after approval, out-of-pocket costs can reach $30–150/month depending on plan design. Manufacturer copay assistance programs reduce this to $0–5/month for most commercially insured patients — the Vault surfaces eligible programs automatically.
Provider type. NPs, PAs, and physicians follow the same PA pathway — documentation standards and payer policies apply identically regardless of provider type. In states with collaborative practice requirements, confirm whether your payer accepts PAs submitted under your NPI directly or requires co-signature.
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Run a PA — free →Citations: AHS 2024 Position Statement — Charles AC et al., Headache 2024;64(4):333-341. doi:10.1111/head.14692 | AHS Consensus 2021 — Ailani J et al., Headache 2021;61(7):1021-1039. doi:10.1111/head.14153 | FDA prescribing information: erenumab, fremanezumab, galcanezumab, eptinezumab, atogepant, rimegepant.