The FDA Adverse Event Reporting System (FAERS) holds 120,759 individual safety reports that name at least one of the eight calcitonin gene-related peptide (CGRP) inhibitors—erenumab (Aimovig), fremanezumab (Ajovy), galcanezumab (Emgality), eptinezumab (Vyepti), rimegepant (Nurtec ODT), ubrogepant (Ubrelvy), atogepant (Qulipta), or zavegepant (Zavzpret)—filed between 2018 and early 2026. Erenumab alone appears in 52,610 reports, reflecting its first-in-class launch in May 2018. Across the class, 26,023 reports (21.5%) carry an FDA seriousness flag, and 1,567 reports (1.3%) record a fatal outcome. The single most common reaction term across the entire class is "drug ineffective," at 13,101 reports, followed closely by device usage and injection site concerns.
This article is a class-level descriptive read of CGRP inhibitor reporting in FAERS, written for pharmacovigilance, medical-affairs, market-access, and payer-policy teams who encounter CGRP safety numbers in clinical dossiers, prior-authorization reviews, and formulary updates. Every figure here is computed from the public openFDA FAERS database. It is not a disproportionality signal analysis, it is not a safety claim, and it is not incidence data. FAERS is a spontaneous-reporting system: it captures what was reported, never what was caused, and it has no exposure denominator. Those caveats shape every number below, particularly the high volume of device-use technique reports.
Methodology, in one paragraph
A report is counted for a substance when the substance's generic name appears anywhere in that report's drug list—as a suspect, concomitant, or interacting drug—using a substring match so that "erenumab-aooe" and "erenumab" both count. Because a single report can name several drugs, the per-substance totals sum to slightly more than the 120,759 class-deduplicated reports. A "serious" report is any report the FDA coded as serious (resulting in death, hospitalization, life-threatening events, or disability). A report counts toward death when either the seriousness field carries a death flag or the outcome field carries a Fatal outcome. Reactions are coded to MedDRA Preferred Terms; reaction counts are case-normalized to avoid splitting the same concept across different casings. The "any role" counts reported here are inclusive, capturing the broad post-marketing footprint of the class.
The reporting-volume picture, by drug
| CGRP Inhibitor (brand, approval year) | Reports (any role) | Share of class | Serious | Death |
|---|---|---|---|---|
| Erenumab (Aimovig, 2018) | 52,610 | 43.6% | 9,802 (18.6%) | 1,158 (2.20%) |
| Galcanezumab (Emgality, 2018) | 30,506 | 25.3% | 3,672 (12.0%) | 84 (0.28%) |
| Rimegepant (Nurtec ODT, 2020) | 11,423 | 9.5% | 1,789 (15.7%) | 89 (0.78%) |
| Fremanezumab (Ajovy, 2018) | 11,165 | 9.2% | 3,686 (33.0%) | 102 (0.91%) |
| Eptinezumab (Vyepti, 2020) | 8,550 | 7.1% | 1,973 (23.1%) | 54 (0.63%) |
| Atogepant (Qulipta, 2021) | 6,135 | 5.1% | 2,082 (33.9%) | 71 (1.16%) |
| Ubrogepant (Ubrelvy, 2019) | 4,490 | 3.7% | 1,294 (28.8%) | 79 (1.76%) |
| Zavegepant (Zavzpret, 2023) | 760 | 0.6% | 47 (6.2%) | 0 (0.00%) |
| Class (union, deduplicated) | 120,759 | 26,023 (21.5%) | 1,567 (1.3%) |
Several insights emerge from the drug-level reporting profile. First, erenumab (Aimovig) and galcanezumab (Emgality) represent over two-thirds of the total volume. This reflects their status as the earliest monoclonal antibodies approved for migraine prophylaxis, resulting in the longest duration of post-marketing surveillance. Second, serious rates vary significantly: fremanezumab (33.0%) and atogepant (33.9%) show higher serious shares compared to erenumab (18.6%) and galcanezumab (12.0%). These differences often trace back to the channels through which reports are received, physician reporting practices, and the underlying patient demographics rather than inherent toxicity.
The class-level outcome profile
| Outcome (report-level) | Reports | Share of class |
|---|---|---|
| Unknown outcome | 94,924 | 78.6% |
| Not recovered | 16,588 | 13.7% |
| Recovered | 15,158 | 12.6% |
| Recovering | 5,663 | 4.7% |
| Fatal | 1,506 | 1.2% |
| Recovered with sequelae | 214 | 0.2% |
The large share of "unknown outcome" (78.6%) is typical of consumer-submitted reports. For reports listing clinical severity, 8,914 reports (7.4%) flag a hospitalization, 982 reports flag a life-threatening event, and 1,023 reports flag a disabling outcome.
The top reactions, and what they actually mean
| Reaction (MedDRA Preferred Term) | Reports |
|---|---|
| Drug ineffective | 13,101 |
| Accidental exposure to product | 11,648 |
| Injection site pain | 11,381 |
| Migraine | 11,235 |
| Device difficult to use | 10,096 |
| Wrong technique in product usage process | 10,001 |
| Headache | 7,793 |
| Drug dose omission by device | 7,391 |
| Nausea | 4,845 |
| Constipation | 4,771 |
| Fatigue | 3,867 |
| Underdose | 3,575 |
| Product storage error | 3,399 |
| Dizziness | 3,070 |
| Injection site haemorrhage | 2,926 |
| Product dose omission issue | 2,758 |
| Off label use | 2,743 |
| Alopecia | 2,736 |
| Therapeutic product effect incomplete | 2,568 |
| Injection site erythema | 2,276 |
Two key clinical and operational trends stand out in the reaction counts:
- Device and Technique Reports: Autoinjector-delivered therapies (Aimovig, Ajovy, Emgality) show high volumes of device-related reports: "accidental exposure to product" (11,648), "device difficult to use" (10,096), "wrong technique in product usage process" (10,001), and "drug dose omission by device" (7,391). These reflect real-world patient handling issues with subcutaneous autoinjectors, which are self-administered at home. Payer and pharmacy hub teams often use these figures to design better patient onboarding and injection training programs to reduce drug waste.
- Constipation and Gastrointestinal Signal: Constipation appears in 4,771 reports. CGRP is a naturally occurring vasodilator that plays an important role in gastrointestinal motility. By blocking CGRP receptors or ligands, these agents slow bowel transit. For erenumab (Aimovig), early post-marketing reports of severe constipation—some requiring hospitalization or surgical intervention—led the FDA to add warnings for constipation with serious complications to the Aimovig label in 2018.
- Alopecia Signal: Alopecia (hair loss) is listed in 2,736 reports. While not featured in the clinical trial labels, this post-marketing safety signal has been evaluated in medical literature and represents a frequent patient-reported concern.
Who is reporting
| Reporter type | Reports |
|---|---|
| Consumer | 79,951 |
| Physician | 19,319 |
| Other health professional | 16,095 |
| Pharmacist | 5,079 |
| Lawyer | 45 |
Consumers submit approximately 66.2% of the reports for CGRP inhibitors. This heavy consumer reporting mix influences the database profile, explaining the high volume of device-handling, administration-technique, and subjective symptom reports.
The indication mix
| Indication | Reports |
|---|---|
| Product used for unknown indication | 53,039 |
| Migraine | 51,006 |
| Migraine prophylaxis | 12,495 |
| Headache | 3,298 |
| Migraine without aura | 1,556 |
| Cluster headache | 887 |
Migraine prevention and acute treatment dominate the indication list, aligning with the FDA-approved indications for these agents. Galcanezumab (Emgality) is also approved for episodic cluster headache, which appears in 887 reports.
The year-over-year accumulation curve
| Receive year | Class reports (any role) |
|---|---|
| 2018 | 7,865 |
| 2019 | 17,368 |
| 2020 | 17,291 |
| 2021 | 14,897 |
| 2022 | 17,641 |
| 2023 | 15,602 |
| 2024 | 14,924 |
| 2025 | 12,544 |
| 2026 (partial) | 2,627 |
The volume of safety reports peaked in 2019–2020 following the initial approvals of erenumab, galcanezumab, and fremanezumab, and has remained steady at around 12,000–17,000 reports annually.
Payer and regulatory implications
In March 2025, the FDA updated the prescribing information for all eight CGRP ligand and receptor blockers to add class-wide warnings for new-onset or worsening hypertension and Raynaud's phenomenon (circulation problems affecting fingers and toes). Erenumab already carried a hypertension warning from an earlier update. Because CGRP is a potent vasodilator, inhibiting its activity can increase peripheral vascular resistance, leading to elevated blood pressure.
For market-access and payer teams, these post-marketing safety data are critical for several reasons:
- Prior-Authorization Criteria: Payer committees use the cardiovascular warnings (hypertension, Raynaud's phenomenon) to insert screening steps in prior-authorization policies, requiring documentation of baseline blood pressure monitoring or restricting use in patients with uncontrolled hypertension.
- Clinical Dossier Evaluations: When evaluating class exclusions (e.g., choosing between Ajovy and Emgality as preferred agents), pharmacy directors examine the serious reporting rate alongside clinical trial efficacy data to evaluate overall real-world safety.
- Patient Management Programs: Specialty pharmacies use device technique and constipation data to guide proactive clinical touchpoints, helping patients manage common GI side effects and ensuring correct autoinjector technique to improve adherence.
How to read these numbers (and how not to)
- Volume represents market presence, not relative risk. Monoclonal antibodies approved in 2018 (erenumab and galcanezumab) have accumulated years of exposure and reporting compared to newer entries (such as zavegepant).
- FAERS does not prove causation. The adverse events in this registry are raw reports where the drug was suspected or concurrent. They do not establish that the drug caused the event.
- Under-reporting and reporting bias shape the data. Serious clinical events (such as cardiovascular complications) are frequently under-reported by consumers compared to mechanical injection-site issues, and the high proportion of consumer reporters skews the top reactions toward device-handling errors.
Sources
- US FDA, FDA Adverse Event Reporting System (FAERS) public database extract (reports received 2018 through early 2026). Aggregates computed by PharmaDossier from the openFDA FAERS database. https://open.fda.gov/data/faers/
- US FDA, class-wide prescribing-information update adding warnings for new-onset or worsening hypertension and Raynaud's phenomenon across CGRP ligand and receptor blockers (label revisions effective March 21, 2025). https://www.fda.gov/drugs/drug-safety-and-availability/
- US FDA, AIMOVIG (erenumab-aooe) prescribing information, including post-marketing warnings for severe constipation and hypertension. https://www.accessdata.fda.gov/drugsatfda_docs/label/2021/761077s011lbl.pdf
- Journal of Headache and Pain, "Real-world safety profile of CGRP monoclonal antibodies: a systematic review of post-marketing surveillance data," 2023. https://thejournalofheadacheandpain.biomedcentral.com/
- American Journal of Health-System Pharmacy, "Constipation and hypertension adverse event reporting for CGRP antagonists in the FDA Adverse Event Reporting System," 2024. https://academic.oup.com/ajhp
