Reported Reactions

Drugs › Muscle relaxant

Generic name

Cyclobenzaprine: adverse event reports filed with FDA

8,750 reports list it as a suspect or interacting product, 2004–2026. Class: Muscle relaxant. Also reported as Cyclobenzaprine /00428402/, Cyclobenzaprine Er, Cyclobenzaprine 10mg.

8,750
reports as suspect product
0% of all reports · about 392 a year
560
reports, 12 months to June 2026
725 in the 12 months before
90.5%
marked serious by the reporter
86.6% across the class
54%
record death among outcomes, as reported
4,724 reports · not verified by FDA

Between March 2004 and June 2026, 8,750 adverse event reports received by FDA list cyclobenzaprine, a generic name as a suspect or interacting product. Reports that mention it only as a concomitant medication (33,970) are left out of every figure here.

In the 12 months to June 2026, 560 reports listed it, down 23% from 725 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Over its reporting history that is about 392 reports a year and 0% of the 20,646,523 reports in the database, and 43.5% of the reports for the muscle relaxant class. How many people take it is not in the data, so a count is not a rate of occurrence.

The MedDRA terms listed most often are toxicity to various agents (23.1%), completed suicide (21.6%) and pain (13.1%). A report can list several reactions, so shares add to more than 100%; 934 different terms appear across these reports. Toxicity to various agents is recorded in 23.1% of these reports, a larger share than in the median muscle relaxant drug (13.4%).

90.5% of the reports are marked serious by the reporter (86.6% across the class); 54% record death among the outcomes and 31.9% record hospitalisation, as reported. 38.5% of the reports came from other health professionals, and the largest patient age group is 45 to 64 (32.4%). FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event."

Reports by month, five years

067133Jul 2021: 83Aug 2021: 29Sep 2021: 57Oct 2021: 60Nov 2021: 46Dec 2021: 672022Jan 2022: 133Feb 2022: 93Mar 2022: 107Apr 2022: 37May 2022: 27Jun 2022: 34Jul 2022: 29Aug 2022: 34Sep 2022: 44Oct 2022: 36Nov 2022: 43Dec 2022: 532023Jan 2023: 93Feb 2023: 92Mar 2023: 28Apr 2023: 68May 2023: 50Jun 2023: 44Jul 2023: 30Aug 2023: 42Sep 2023: 30Oct 2023: 82Nov 2023: 33Dec 2023: 432024Jan 2024: 69Feb 2024: 75Mar 2024: 56Apr 2024: 36May 2024: 46Jun 2024: 33Jul 2024: 47Aug 2024: 30Sep 2024: 21Oct 2024: 46Nov 2024: 66Dec 2024: 1172025Jan 2025: 102Feb 2025: 52Mar 2025: 44Apr 2025: 83May 2025: 17Jun 2025: 100Jul 2025: 84Aug 2025: 36Sep 2025: 43Oct 2025: 30Nov 2025: 46Dec 2025: 502026Jan 2026: 80Feb 2026: 64Mar 2026: 19Apr 2026: 45May 2026: 33Jun 2026: 30

Reports by the month FDA received them. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.

By year received

04148282004: 1520042005: 192006: 92007: 620072008: 252009: 622010: 16220102011: 2072012: 2572013: 45320132014: 4402015: 5292016: 37020162017: 4732018: 4092019: 82820192020: 8052021: 7762022: 67020222023: 6352024: 6422025: 68720252026: 271

2026 covers reports received through June 2026 only.

Reactions recorded in the reports

share of Cyclobenzaprine reports recording the termmedian drug in muscle relaxant

  1. Toxicity to various agentspoisoning or toxic effect of one or more substances23.1%2,024
  2. Completed suicidedeath by suicide21.6%1,889
  3. Painpain, site not specified13.1%1,142
  4. Drug abusemisuse of a medicine11.5%1,007
  5. Constipationconstipation8.9%777
  6. Off label useused for a purpose or in a way not on the label8.5%744
  7. Hypotensionlow blood pressure8.2%719
  8. Drug ineffectivethe medicine did not work as expected8%699
  9. Falla fall7.9%695
  10. Overdosea dose above the recommended amount7.4%651
  11. Drug hypersensitivityan allergic-type reaction to a medicine7.1%623
  12. Mobility decreasedreduced ability to move about6.6%575
  13. Cognitive disorderproblems with thinking or memory6.5%572
  14. Sedationdrowsiness from a medicine6.5%572
  15. Hepatic enzyme increasedraised liver enzymes6.4%558
  16. Balance disorderproblems with balance6.4%557
  17. Headachehead pain6.3%550
  18. Drug intolerancethe medicine was not tolerated6.1%530
  19. Exposure during pregnancythe medicine was taken during pregnancy6%524
  20. Hypertensionhigh blood pressure6%521
  21. Infusion related reactiona reaction during or soon after an infusion5.8%509
  22. Rheumatoid arthritisrheumatoid arthritis, an inflammatory joint disease5.8%505
  23. Deaththe patient died; cause not stated by this term5.7%502
  24. Joint swellinga swollen joint5.4%470
  25. Creatinine renal clearance decreased5.3%461
  26. Sedation complication5.2%455
  27. Hypersensitivityan allergic-type reaction5.1%444

Top 30 of 934 MedDRA preferred terms recorded across these reports, with a plain-language gloss where one is available. One report can record several terms. The hollow bar is the median share across the 8 drugs in the muscle relaxant class; it describes the reports, not the patients. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Outcomes recorded

Death54%4,724
Life-threatening8.1%709
Hospitalisation (initial or prolonged)31.9%2,791
Disability4.3%373
Congenital anomaly4.1%359
Other serious48.2%4,218
Not serious9.5%832

Outcome flags as the reporter set them; a report can carry several, and "other serious" is FDA's own category for serious reports outside the named outcomes. Grey bar: all 20,135 reports in the class. FDA has not verified any outcome and states that the reports "cannot be used to estimate the incidence of these events."

Patients and reporters

Patient age

Under 20.7%64
2 to 110.1%10
12 to 172.1%182
18 to 4428.8%2,524
45 to 6432.4%2,838
65 to 745.9%518
75 and over8.5%747
Age not given21.3%1,867

Patient sex

Female63.8%5,583
Male25.3%2,214
Not given10.9%953

Who reported

Physician34.7%3,032
Pharmacist10.5%917
Other health professional38.5%3,369
Lawyer0.3%30
Consumer or non-health professional13.2%1,156
Not given2.8%246

Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 70.6% of reports give the United States as the country of the event or reporter.

Reason for use recorded

Indication as recorded (MedDRA)ReportsShare
Eczema3884.4%
Pain3744.3%
Muscle spasms1591.8%
Fibromyalgia1391.6%
Suicide attempt1371.6%
Back pain1171.3%

The indication field is filled in by the reporter and is often blank; shares are of all 8,750 reports.

Drugs most often listed in the same reports

Drug (any role in the report)ReportsShare of Cyclobenzaprine reports
Acetaminophen1,87721.5%
Gabapentin1,58418.1%
Oxycodone1,08212.4%
Furosemide1,04511.9%
Actemra8519.7%
Albuterol8269.4%
Vitamin c8129.3%
Rituximab7919%
Hydromorphone7718.8%
Omeprazole7418.5%

Other products listed in reports where Cyclobenzaprine is a suspect product, whatever their own role. Co-listing means the two were recorded together; it says nothing about either product's part in the event. Only the 2,500 most-reported names are counted here.

In context

MeasureCyclobenzaprineMuscle relaxantAll reports
Reports as suspect product8,75020,13520,646,523
Share of that pool—43.5%0%
Reports, latest 12 months560—1,332,454
Marked serious90.5%86.6%57.4%
Death recorded among outcomes, per 1,000 reports54051291
Hospitalisation recorded, per 1,000 reports319265213
Consumer-filed share13.2%18.6%45.8%
Top term, share of reportsToxicity to various agents 23.1%median 13.4%0.8%

Shares are of reports, not of patients treated. The number of people taking a product is not in the data, so none of these figures is a rate, and differences between columns reflect who takes a product, who reports and how long it has been sold. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Other drugs in the muscle relaxant class

DrugName typeReportsLatest 12 monthsMarked serious
Carisoprodolgeneric4,0952892.1%
Methocarbamolgeneric2,11124579.6%
Cyclobenzaprine hydrochloridegeneric1,59111586.3%
Somabrand1,316576.3%
Metaxalonegeneric9251273.7%
Cyclobenzaprine hclgeneric763088.1%
Robaxinbrand5842957.5%

Ordered by report count for navigation only. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic." A brand and its generic are separate rows because reporters name them separately.

Questions about Cyclobenzaprine reports

How many adverse event reports has FDA received for Cyclobenzaprine?

8,750 reports list Cyclobenzaprine as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 560 of them arrived in the latest 12 months. Another 33,970 list it only as a concomitant medication.

What reactions are recorded in Cyclobenzaprine reports?

toxicity to various agents (23.1%), completed suicide (21.6%), pain (13.1%), drug abuse (11.5%) and constipation (8.9%). These are MedDRA preferred terms coded from what the reporter described; a report can list several, and a term's presence is not a finding that Cyclobenzaprine was responsible.

How serious are the reports?

90.5% are marked serious by the reporter. Among the outcomes recorded, 54% of reports include death and 31.9% include hospitalisation. FDA has not verified these outcomes and states that the reports "cannot be used to estimate the incidence" of the events.

Who files these reports?

other health professional (38.5%), physician (34.7%) and consumer or non-health professional (13.2%). Most reports reach FDA through the manufacturer, which must forward reports it receives.

Are reports for Cyclobenzaprine rising?

560 reports in the 12 months to June 2026, down 23% from 725 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Counts also move with how many people take a product, its time on the market and publicity.

Do these reports show that Cyclobenzaprine was responsible for these reactions?

No. FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event." The reaction may relate to the condition being treated, to other medicines, or to something else.

Is this a list of the side effects of Cyclobenzaprine?

No. It is a count of what was reported to FDA. The adverse reactions observed in clinical studies are printed on the FDA-approved label, which a pharmacist or clinician can go through with you.

How do I report an adverse event?

Consumers and health professionals can report to FDA through MedWatch (Form FDA 3500 online, or 1-800-FDA-1088), or to the manufacturer, which must pass reports on. See the guide on how to report.

Where this comes from. Counts are built from the openFDA Drug Adverse Event (FAERS) bulk export released 28 Sep 2026, which holds reports FDA received through 30 Jun 2026. Drug names are as reported, resolved to the brand or generic name on the FDA label where openFDA's harmonisation matched them; classes are the pharmacologic class (EPC) from the label and the National Drug Code Directory of 17 Sep 2026. A report counts here when it lists Cyclobenzaprine as a suspect or interacting product; reports listing it only as a concomitant medication (33,970) are excluded. No report narrative, lot number, patient detail or reporter identity is published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.

Drug data (FAERS) through 30 Jun 2026; device data (MAUDE) through 31 Aug 2026. Not medical advice.