Cyclobenzaprine hydrochloride: adverse event reports filed with FDA

1,591

reports as suspect product

0% of all reports · about 71 a year

115

reports, 12 months to June 2026

111 in the 12 months before

86.3%

marked serious by the reporter

86.6% across the class

28.1%

record death among outcomes, as reported

447 reports · not verified by FDA

Reports by month, five years

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

2026 covers reports received through June 2026 only.

Reactions recorded in the reports

share of Cyclobenzaprine hydrochloride reports recording the termmedian drug in muscle relaxant

1. Painpain, site not specified44.4%707
2. Constipationconstipation33.4%531
3. Headachehead pain24.1%383
4. Hepatic enzyme increasedraised liver enzymes23.6%375
5. Off label useused for a purpose or in a way not on the label23.3%371
6. Rheumatoid arthritisrheumatoid arthritis, an inflammatory joint disease23.3%370
7. Hyperhidrosisexcessive sweating22.8%363
8. Hypersensitivityan allergic-type reaction22.7%361
9. Immunodeficiency22.6%360
10. Food allergy22.1%352
11. Asthmaasthma21.1%336
12. Drug hypersensitivityan allergic-type reaction to a medicine20.9%332
13. Upper respiratory tract infectiona cold or similar infection20.7%329
14. Toxicity to various agentspoisoning or toxic effect of one or more substances20.6%327
15. Rash erythematousa red rash20.5%326
16. Fatiguetiredness20.3%323
17. Fluid retentionthe body holding extra fluid19.7%313
18. Temperature regulation disorder19.5%310
19. Bursitis19.4%308
20. Drug intolerancethe medicine was not tolerated19.3%307
21. Coeliac disease18.9%301
22. Drug ineffectivethe medicine did not work as expected18.7%298
23. Erythemaskin redness18.4%292
24. Back painback pain18.3%291
25. Overdosea dose above the recommended amount18.1%288
26. Contraindicated product administered16.6%264
27. Falla fall16.3%259
28. Hypotensionlow blood pressure16%254
29. Depressed level of consciousness15.8%252
30. Cognitive disorderproblems with thinking or memory15.7%250

Top 30 of 437 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

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

Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 44.1% of reports give the United States as the country of the event or reporter.

Reason for use recorded

The indication field is filled in by the reporter and is often blank; shares are of all 1,591 reports.

Drugs most often listed in the same reports

Other products listed in reports where Cyclobenzaprine hydrochloride 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

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

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.

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 hydrochloride as a suspect or interacting product; reports listing it only as a concomitant medication (6,590) 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.