CGRP prior auth counts your headache days and drops the days after.
CGRP step-therapy criteria are built on headache days, so the 24 to 72 hours after each attack never reach the prior-auth record. Here's how to document both halves honestly, before a denial.
The prior-auth form has room for one number
The prior-authorization form asks how many headache days you had last month. You check your diary and count nine, so your neurologist's office writes down 9. That number now decides whether your plan pays for a CGRP preventive or sends you back to try another older pill first.
Nine is accurate. It's also half the story.
Every one of those nine attacks had an after-phase. There was the heavy-limbed day when light still stung, the afternoon you read one email four times, and the neck that wouldn't turn to check a blind spot. None of it went in the diary because the headache was over. So it isn't in the chart, and the reviewer at your insurer will never see it.
The half-ledger: the attack gets counted, the aftermath doesn't
We call this the half-ledger. Step-therapy criteria for the CGRP antibodies (Aimovig, Ajovy, Emgality) are written around headache days. That's the unit the International Headache Society uses to define chronic migraine in ICHD-3, and payer policies inherited it. So the eligibility math counts the attack and stops there.
The other half of the ledger is well documented. In a 2016 electronic-diary study in Neurology, Giffin and colleagues found that 81% of participants had at least one non-headache symptom after the pain resolved. Tiredness, trouble concentrating and neck stiffness were near the top of the list.
An appeal won't argue the half-ledger away. You can close most of it months before anyone fills in a form, and that's what the rest of this piece covers.
Why 'just keep a headache diary' undersells you
The standard advice before a CGRP request is to keep a headache diary for a few months. That's good advice as far as it goes. But a headache diary is built to record headaches, so it stops recording when the pain does.
Two kinds of day fall through. The first is residual-pain days. If your head still aches faintly on day two, that counts as a headache day under the definitions criteria use. Plenty of people skip it anyway because the "real" migraine ended yesterday. Those days count, and they probably aren't on your log.
The second is impairment days. A postdrome day with no head pain isn't a headache day and shouldn't be logged as one. It still belongs in the record, because disability is the other thing clinicians and some payer criteria weigh. And a lot of the disability happens in postdrome.
The opposite instinct backfires too. If you pad the headache count with postdrome days to clear a threshold, it will fall apart the first time a neurologist asks what happened on those days. Being accurate gets you further.
How many headache days does CGRP prior authorization require?
It depends on the plan and on whether the request is for episodic or chronic migraine, but the unit is almost always days with headache or migraine. For chronic migraine, the benchmark is ICHD-3: headache on 15 or more days a month for more than three months, with migraine features on at least 8 of those days.
Carrier policies set their own thresholds for episodic prevention, and those numbers differ from one insurer to the next. Most also require documented trials of older preventive classes before a CGRP antibody, which is the "step" in step therapy. Because the exact wording changes by plan and gets revised over time, check the current coverage criteria for your specific plan, whether that's Cigna, UnitedHealthcare, or another carrier. Your prescriber's office or the insurer's published policy for Aimovig, Ajovy, and Emgality will have the threshold that applies to you.
Postdrome can legitimately show up in disability measures. MIDAS, the questionnaire many headache clinics use, asks over a three-month window how many days you missed work, school, housework or social plans, or got through them at half capacity or less.
Source
What it counts
Threshold
Does a pain-free postdrome day register?
ICHD-3 chronic migraine definition
Headache days, plus days with migraine features
15+ headache days a month for more than 3 months; 8+ with migraine features
No
Cigna CGRP mAb policy
Cigna's Aimovig prior authorization policy requires patients to have at least 4 migraine headache days per month before starting a migraine-preventive medication, counting migraine days as the unit. ([source](https://static.cigna.com/assets/chcp/pdf/coveragePolicies/cnf/cnf_331_coveragepositioncriteria_calcitonin_gene-related_peptide_inhibitors_aimovig_pa.pdf))
Cigna's Qulipta prior authorization policy requires the patient to have ≥4 migraine headache days per month before initiating a migraine-preventive medication. ([source](https://static.cigna.com/assets/chcp/pdf/coveragePolicies/cnf/cnf_708_coveragepositioncriteria_migraine_qulipta_pa.pdf))
Cigna's Emgality prior authorization policy includes a functional disability criterion, listed as 'Functional Disability MIDAS' (Migraine Disability Assessment). ([source](https://www.counterforcehealth.org/post/work-with-your-doctor-to-get-emgality-galcanezumab-gnlm-covered-by-cigna-in-pennsylvania-appeals-guide/))
UnitedHealthcare CGRP mAb policy
UnitedHealthcare's CGRP criteria require a migraine diagnosis with fewer than 15 headache days per month, or at least 8 migraine days per month. ([source](https://www.uhcprovider.com/content/dam/provider/docs/public/prior-auth/drugs-pharmacy/commercial/a-g/PA-Med-Nec-CGRP-Receptor-Antagonists.pdf))
UnitedHealthcare sets its own threshold for this, and the exact cutoff depends on your plan and the policy currently in effect. Check your plan documents or call the number on your member card to confirm the current requirement before you plan around it.
Cigna's Emgality prior authorization policy includes a functional disability criterion, listed as 'Functional Disability MIDAS' (Migraine Disability Assessment). ([source](https://www.counterforcehealth.org/post/work-with-your-doctor-to-get-emgality-galcanezumab-gnlm-covered-by-cigna-in-pennsylvania-appeals-guide/))
MIDAS questionnaire
Days missed or at half capacity or less, across work, home and social life
3-month recall window
Yes, when the day cost you function
Frequency criteria count head pain. Disability measures are where postdrome legitimately shows up.
The arithmetic: eight attacks, 48-hour tails
Here's a worked example. Take a hypothetical patient with eight attacks a month. Each attack is one headache day, followed by about 48 hours of postdrome.
Their headache diary shows 8 days, which is well under the chronic threshold. Their actual impaired days come to 8 plus 16, or 24 out of a 30-day month. That leaves six clear days.
Now suppose three of those attacks left faint head pain on day two that never got logged. Those are headache days, so the honest count goes from 8 to 11. That's still under 15, and it should stay there. The extra three days are a correction, not inflation.
The postdrome days do their work somewhere else. Over a three-month MIDAS window, the recovery days when this patient worked at half speed or less are now written down instead of guessed at in the exam room. The frequency number stays honest, and the disability number finally reflects the month they actually had.
Illustrative arithmetic for a hypothetical patient (8 one-day attacks, ~48-hour postdromes, 3 unlogged residual-pain days). Not study data.
What to start logging three months before the request
Three months is the window ICHD-3 uses for chronic migraine, and it's also the window MIDAS asks about. So start at least that far ahead of the appointment where a CGRP request might come up.
Log every day, including the clear ones. A record with gaps reads as a record with doubts. Any day with head pain, however faint, goes down as a headache day. Recovery days go down separately, with what they cost you: a missed shift, a meeting you sat through at half capacity, a school pickup someone else covered.
Keep the step part documented too. Write down every preventive you've tried, with dates, dose and why it stopped, whether that was side effects or not enough effect. Step therapy runs on documented failures, and memory is a bad record.
Bring all of it to your neurologist and ask them to use it for the MIDAS score and the request.
Never relabel a postdrome day as a headache day
If there was no head pain, it isn't a headache day, however wrecked you felt. Log it as recovery, with its functional cost. Inflated counts can sink credibility with your clinician and with the reviewer.
Where Postdrome fits
We built Postdrome because every tracker we tried stopped at the headache, while the people we love kept losing the next two days anyway. The app treats the after-phase as its own state on a continuous timeline. You log the attack, then the fog, the light sensitivity, the stiff neck and what each one cost you, without having to call any of it a headache.
Head pain on a recovery day is recorded as head pain, so it counts where it should. When the office asks for a frequency number, you have an honest one. When they ask how disabled you are, you have the other half. And Aura Mode keeps logging possible on days when you can barely look at a screen.
What we're tracking next
Two things. In 2024 the American Headache Society published a position statement naming CGRP-targeting therapies a first-line preventive option. We're watching whether carriers rewrite their step-therapy policies in response, which would shorten the step itself.
We're also watching for any carrier policy that starts asking about functional impairment between attacks. When one does, patients with three months of complete records will be ready the same week.
Start the three-month log your next prior-auth request will lean on.
Postdrome logs the 24 to 72 hours after an attack as its own phase, separate from headache days, so your record stays accurate on frequency and complete on disability. Your data stays on your device, you can export it, and pricing is lifetime instead of a subscription.
