Morphine and Cyclobenzaprine Interaction

Drug interaction information between Morphine and Cyclobenzaprine.

Morphine and Cyclobenzaprine have a documented minor interaction in FDA labeling.

FDA drug labeling documents a minor-severity interaction between Morphine 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.

Drug A

Morphine

Opioid Analgesic

Drug B

Cyclobenzaprine

Muscle Relaxant

How They Interact

This muscle relaxant affects the serotonin system in your body. When combined with morphine, it can increase the risk of a dangerous condition called serotonin syndrome.

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). Examples: Cyclobenzaprine, metaxalone Cimetidine Clinical Impact: The concomitant use of morphine...

Frequently Asked Questions

What SPL severity band is on file for Morphine + 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?

Morphine has 30 labeled pairs on file vs Cyclobenzaprine's 17. In the minor band specifically: Morphine has 30 (also Trazodone, Tramadol, Mirtazapine, Verapamil); Cyclobenzaprine has 14 (also Acetaminophen/Oxycodone, Buprenorphine, Buprenorphine/Naloxone, Buprenorphine).

What mechanism field is on file for Morphine and Cyclobenzaprine?

This muscle relaxant affects the serotonin system in your body. When combined with morphine, it can increase the risk of a dangerous condition called serotonin syndrome.

Morphine's labeled portfolio outnumbers Cyclobenzaprine

SPL source-record counts only. This page's band is minor · classes on file: Morphine (Opioid Analgesic); Cyclobenzaprine (Muscle Relaxant).

Morphine

0 major · 0 moderate · 30 minor · 30 total

Cyclobenzaprine

0 major · 3 moderate · 14 minor · 17 total

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.