If you’re considering Botox for chronic migraine prevention, this guide walks you through who qualifies, the exact dosing and map used in clinic, how quickly it works, safety and side effects, real costs and insurance steps, and how to measure whether it’s worth continuing.
You’ll come away with practical details you can use at your next visit, from the PREEMPT protocol dosing to HIT-6/MIDAS tracking and coverage codes.
Overview
Botox is the only neuromodulator FDA‑approved specifically for chronic migraine, which is defined as 15 or more headache days per month with at least 8 migraine days for over 3 months. Chronic migraine is a clinical diagnosis based on the ICHD‑3 chronic migraine criteria, and the approval covers adults who meet this threshold, as detailed in the FDA BOTOX label.
While some people also ask about episodic migraine, the on‑label use—and the strongest coverage support—is for chronic migraine only. If you track your headache days for 30–90 days and land at or above the ICHD‑3 threshold, you’re in the right place to evaluate Botox as a preventive.
Who qualifies for Botox and how it works
Botox (onabotulinumtoxinA) is typically offered to adults with chronic migraine who have tried at least one or two oral preventives and still have significant disability. The FDA approved onabotulinumtoxinA for chronic migraine in 2010 based on the PREEMPT trials, and most insurers align their criteria to that label and to ICHD‑3; see the FDA BOTOX label for the formal indication.
It prevents rather than treats attacks, so it’s used on a fixed schedule independent of acute medication use. If you’re close to the 15‑day threshold or have medication overuse, a specialist can help fine‑tune the plan and documentation.
Eligibility checklist
Most clinics and payers look for the following before starting onabotulinumtoxinA for chronic migraine:
- Headache frequency: ≥15 headache days/month for ≥3 months, with ≥8 migraine days (ICHD‑3 aligned).
- Prior preventive trials: Typically ≥2 classes tried or not tolerated (e.g., topiramate, beta‑blocker, SNRI).
- Age and diagnosis: Adult with a clinician‑confirmed chronic migraine diagnosis.
- Baseline documentation: 30–90 days of a headache diary plus disability scale (HIT‑6 or MIDAS).
- Practical considerations: No active infection at injection sites and no absolute contraindication.
Bring your diary and a list of prior preventives (dose/duration/outcomes) to your consultation to speed approval.
Mechanism in plain language
Botox calms overactive pain pathways by blocking the release of pain‑signaling chemicals from nerve endings in the head and neck. In practice, that neuromodulation reduces the frequency and intensity of attacks over weeks.
It does not abort an attack that’s already underway. Because nerves gradually regenerate, treatments are repeated every 12 weeks for maintenance.
If you think of migraine as an overly “sensitized” system, Botox helps turn the volume down between attacks.
PREEMPT protocol and dosing specifics for chronic migraine
The PREEMPT protocol uses 155–195 Units of onabotulinumtoxinA injected across 31 standardized sites every 12 weeks, with up to 40 additional Units in “follow‑the‑pain” areas. The base map includes the forehead, temples, back of the head, neck, and upper shoulders, typically 5 Units per site for 31 sites (total 155 U).
An extra 10–40 Units can be added for predominant pain regions. This precise template comes from the pivotal trials in chronic migraine, known collectively as the PREEMPT clinical program. Your provider may adjust within the 155–195 U range based on response and side effects.
If you want a quick snapshot to save: 31 injections, 155–195 total Units, every 12 weeks.
Injection map and when dosing is adjusted
The standardized sites target muscles that interface with pain‑sensing nerves: corrugator and procerus (between the brows), frontalis (forehead), temporalis (temples), occipitalis (back of the head), cervical paraspinals (neck), and trapezius (upper shoulders). Providers add “follow‑the‑pain” Units where your pain concentrates, often in temporalis or occipital areas.
They may reduce Units in areas that caused unwanted weakness, such as less in frontalis if brow ptosis occurred. Injector experience matters because subtle technique—depth, angle, and dosing across muscle zones—can influence both relief and side effects.
Ask your clinician how they tailor PREEMPT to your pattern and what changes they’d make if you have a partial response.
What to expect on treatment day
Most visits take 15–30 minutes, and you can drive and return to work right after. After a quick review of your diary and any side effects, the clinician prepares the medication and performs a series of small injections across the mapped areas.
Expect a pinprick sensation and occasional brief sting. Bleeding is minimal, and bruises, if they occur, are usually small. For aftercare, you’ll typically avoid rubbing the injected areas, strenuous exercise, or facials for the first 24 hours.
Plan a 12‑week follow‑up or add‑on scheduling at checkout so your next cycle lands on time.
Needles, numbing, and pain control
Clinics usually use very fine needles—often 30–32 gauge, 0.5‑inch—so most people describe the discomfort as mild and fleeting. You can request topical anesthetic or ice if you’re sensitive; many centers offer ice packs before and after to dull any stings and reduce bruising.
If you bruise easily, ask about gentle pressure immediately after each injection and icing for 10–15 minutes when you get home. You can also ask your clinician whether pausing elective, non‑prescribed supplements that thin blood is appropriate for you in the week prior.
Efficacy timeline and real-world outcomes
You’ll usually feel the first benefits in 1–3 weeks, with the most consistent gains after 2–3 treatment cycles. In studies and clinical practice, many patients see a 30%–50% reduction in monthly headache days, and some achieve even greater relief with successive cycles, consistent with the PREEMPT clinical program.
Long‑term, durability looks strong. In the 108‑week COMPEL long‑term study, participants sustained meaningful reductions in headache days and disability with repeated cycles.
Individual results vary, especially if medication overuse or comorbid conditions are in the mix. Track baseline and each cycle’s outcomes so you can make a data‑based decision by the third session.
What improvement typically looks like
For most people, improvement shows up as fewer monthly headache and migraine days, lower pain intensity, and less time lost from work or activities. You might notice that attacks are shorter, respond better to your acute medication, or skip certain high‑trigger weeks altogether.
Disability scores (HIT‑6 or MIDAS) often drop as the months go on, even when the absolute day count reduction is modest at first. Be on the lookout for “good weeks” expanding between cycles—a common pattern as the benefit accumulates.
Bring your diary to each visit and flag which domains matter most to you, such as work days missed, bedtime pain, or morning spikes.
Safety, side effects, contraindications, and interactions
Botox for chronic migraine is generally well‑tolerated. The most common effects are injection‑site pain, small bruises, neck soreness, and temporary neck weakness.
Rarely, toxin effects can diffuse and cause eyelid droop, difficulty swallowing, or voice changes. Call your clinician promptly if you notice these or any breathing difficulty.
Absolute contraindications include known hypersensitivity to onabotulinumtoxinA and active infection at the injection sites. Caution is advised with neuromuscular junction disorders, such as myasthenia gravis or Lambert–Eaton, and ALS.
Drug interactions to discuss include aminoglycoside antibiotics and other agents that affect neuromuscular transmission, as these can potentiate effects. Core safety language is outlined in the FDA BOTOX label.
For lactation counseling, current evidence suggests minimal risk, but decisions are individualized. Review specifics with your clinician and resources like LactMed: Botulinum Toxin.
Special populations and counseling considerations
Adolescents and older adults may still be considered on a case‑by‑case basis, but only adults have on‑label approval for chronic migraine. In older adults, providers sometimes adjust sites prone to weakness, such as frontalis or neck, and monitor for balance‑affecting side effects.
For pregnancy, data are limited. Many clinicians defer initiation unless benefits clearly outweigh risks, while those already stable on therapy may consider cycle‑by‑cycle decisions.
On anticoagulants or antiplatelets, most patients can proceed without stopping therapy, but bruising risk is higher. Expect gentle technique, pressure, and ice; never stop blood thinners without your prescriber’s guidance.
If you have a neuromuscular disorder or severe frailty, make sure a headache specialist is directly involved in risk–benefit and dose mapping.
Combining Botox with CGRP monoclonal antibodies or gepants
Botox and CGRP‑targeted therapies prevent migraine via different pathways, and many specialists combine them for refractory chronic migraine. Compared with CGRP monoclonal antibodies or oral gepants alone, onabotulinumtoxinA can offer additive reductions in monthly migraine days and improved function when used together, especially after a partial response to either agent.
Side effects also tend to be non‑overlapping. Botox’s local effects, like neck soreness, differ from CGRP mAbs’ constipation or injection‑site reactions and gepants’ nausea or rare liver enzyme elevations.
There are no large head‑to‑head RCTs directly comparing percent reductions, so decisions hinge on your response, tolerance, and insurance. If you’re at 30%–49% improvement after 2–3 Botox cycles, discuss adding a CGRP monoclonal antibody or daily gepant to reach your goals.
Managing medication overuse headache alongside Botox
Medication overuse headache (MOH) happens when frequent use of acute meds keeps the pain cycle “switched on.” That’s typically more than 10 days per month for triptans or combination analgesics, or more than 15 for simple analgesics.
Subgroup analyses from the Botox chronic migraine trials show patients with MOH still improve. Outcomes are best when acute medications are tapered while preventive therapy starts.
A common approach is to set a taper or switch plan for acute meds, consider bridge strategies if needed, and set clear “rules” for rescue use in the first 2–3 cycles. Expect the first cycle to feel like a reset month while overuse is addressed.
Your diary will help confirm when you move out of the MOH zone.
Cost, insurance coverage, and billing codes
Out‑of‑pocket costs vary widely, but a typical cash total (drug plus procedure) ranges from about $1,200 to $2,500 per 12‑week cycle. Dose, clinic markup, and facility fees drive the range, with dosing between 155–195 U.
Coverage is common for on‑label use when criteria are met. Clinics bill the drug with J‑code J0585 (onabotulinumtoxinA, per Unit) and the injection procedure with CPT 64615.
Practices either “buy‑and‑bill” (clinic purchases the drug and bills your medical benefit) or use a specialty pharmacy (your pharmacy benefit supplies the drug; the clinic bills only the procedure). Insurers often follow frameworks such as the UK’s NICE guidance on Botox for chronic migraine, requiring baseline documentation and proof of benefit to renew.
To speed prior authorization, work through these steps:
- Confirm you meet ICHD‑3 criteria and gather a 30–90 day diary showing ≥15 headache days (≥8 migraine days).
- List prior preventive trials (name, dose, dates, outcomes/intolerances), ideally from two or more classes.
- Complete a HIT‑6 and/or MIDAS at baseline and bring scores to the visit.
- Ensure your clinician’s notes include “chronic migraine” and the PREEMPT protocol dose (155–195 U, every 12 weeks).
- If denied, request a peer‑to‑peer review and submit a letter of medical necessity referencing the FDA label and your documented disability.
Off-label uses: episodic migraine, vestibular migraine, and post-traumatic headache
While on‑label use targets chronic migraine, some clinicians consider off‑label Botox for episodic migraine with frequent disability, vestibular migraine, post‑traumatic headache, or occipital neuralgia. Evidence in these groups is mixed and generally less robust than the PREEMPT data.
Small trials and case series suggest potential benefit for selected patients. Coverage is less predictable off‑label, and insurers may deny without chronic migraine documentation and on‑label dosing.
If you’re exploring these scenarios, ask for a clear plan to measure response within 2–3 cycles and a backup strategy if benefit is insufficient. For many, CGRP‑targeted therapies or nerve blocks may be better first off‑label steps.
Tracking outcomes, response definitions, and stop/continue rules
Good documentation is your superpower. The right data help you and your insurer decide whether to continue after 2–3 cycles.
Use a simple diary to log headache/migraine days, intensity, and acute medication use, and complete a disability score every cycle. The validated HIT‑6 questionnaire (clinically meaningful change ≈ 5 points) and MIDAS scoring guide (category shifts) make progress visible beyond day counts.
A practical algorithm after 2–3 cycles:
- Continue: ≥50% reduction in monthly migraine days or clinically meaningful improvement in HIT‑6/MIDAS; maintain dose and interval.
- Adjust: 30%–49% improvement; consider increasing to 195 U, adding CGRP mAb/gepant, or optimizing MOH taper and sleep triggers.
- Switch/stop: <30% improvement or intolerable side effects; consider transitioning to CGRP therapies or alternative preventives.
Reassess every 2–3 cycles. If you convert to episodic migraine and remain stable for several cycles, discuss whether to extend intervals or trial a pause.
Choosing a qualified injector
Outcomes and side effects improve when your injector follows PREEMPT precisely and tailors dosing to your pain map. Look for a board‑certified neurologist or headache specialist with high volume in migraine prevention injections and familiarity with onabotulinumtoxinA for chronic migraine.
Ask how many PREEMPT patients they treat monthly, how they handle MOH, and what they adjust if brow heaviness or neck weakness occurs. A confident injector should be able to describe the 31‑site map, when they add “follow‑the‑pain” Units, and how they measure response with HIT‑6/MIDAS.
Choose someone who welcomes your diary and explains their plan for the first three cycles.
Preparation, bruise minimization, and aftercare
A little prep reduces bruising and makes the visit smoother. With your clinician’s approval, ask if you should pause elective blood‑thinning supplements like high‑dose fish oil, garlic, ginkgo, or vitamin E for 5–7 days before injections; do not stop prescription anticoagulants or antiplatelets unless your prescriber directs otherwise.
Arrive well‑hydrated, avoid heavy hats or headbands that press on injection sites afterward, and consider an ice pack for 10–15 minutes post‑visit to quiet tenderness.
Aftercare is simple: avoid rubbing or massaging injected areas, strenuous exercise, hot yoga/sauna, or facial treatments for about 24 hours. Try not to lie flat or face‑down for the first 4 hours.
Mild soreness responds to ice or acetaminophen. Skip NSAIDs if you’re bruise‑prone unless your clinician approves.
Mark your calendar for the next 12‑week cycle and keep logging your headache days so you can see the trend clearly.