Fentanyl and Cyclobenzaprine Interaction
Drug interaction information between Fentanyl and Cyclobenzaprine.
Fentanyl and Cyclobenzaprine have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Fentanyl and Cyclobenzaprine. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.
How They Interact
Both drugs increase the level of a brain chemical called serotonin. Taking them together can cause too much serotonin to build up in your body, which can be dangerous.
FDA Label Information
Examples: Selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), triptans, 5-HT3 receptor antagonists, drugs that effect the serotonin neurotransmitter system (e.g., mirtazapine, trazodone, tramadol), certain muscle relaxants (i.e., cyclobenzaprine, metaxalone), monoamine oxidase (MAO) inhibitors (those intended to treat psychiatric disorders and also others, such as linezolid and intravenous methylene blue).
Fentanyl Also Interacts With
- Itraconazole moderate
- Tranylcypromine moderate
- Tramadol minor
- Ketoconazole minor
- Diazepam minor
Cyclobenzaprine Also Interacts With
- Clozapine moderate
- Tapentadol moderate
- Tranylcypromine moderate
- Acetaminophen/Oxycodone minor
- Buprenorphine minor
Frequently Asked Questions
What SPL severity band is on file for Fentanyl + Cyclobenzaprine?
Compiled FDA labeling labels this pair minor. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Fentanyl has 28 labeled pairs on file vs Cyclobenzaprine's 17. In the minor band specifically: Fentanyl has 26 (also Tramadol, Ketoconazole, Diazepam, Carbamazepine); Cyclobenzaprine has 14 (also Acetaminophen/Oxycodone, Buprenorphine, Buprenorphine/Naloxone, Buprenorphine).
What mechanism field is on file for Fentanyl and Cyclobenzaprine?
Both drugs increase the level of a brain chemical called serotonin. Taking them together can cause too much serotonin to build up in your body, which can be dangerous.
Fentanyl's labeled portfolio outnumbers Cyclobenzaprine
SPL source-record counts only. This page's band is minor · classes on file: Fentanyl (Opioid Analgesic); Cyclobenzaprine (Muscle Relaxant).
0 major · 2 moderate · 26 minor · 28 total
- Other minor peers for Fentanyl
- Tramadol
- Ketoconazole
- Diazepam
- Carbamazepine
0 major · 3 moderate · 14 minor · 17 total
- Other minor peers for Cyclobenzaprine
- Acetaminophen/Oxycodone
- Buprenorphine
- Buprenorphine/Naloxone
- Buprenorphine
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. This registry does not provide individual medication-combination directions.
Read our methodology - how this data is sourced, computed, and verified.