What the FDA labels say about taking them together
Cyclobenzaprine and hydromorphone
Hydromorphone's FDA label of May 14, 2026 names cyclobenzaprine in its drug interactions section; the cyclobenzaprine labels PlainMeds reads (3) do not name hydromorphone. The hydromorphone label: “The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.”
Check it at the source: the cyclobenzaprine FDA label on DailyMed (effective February 21, 2025, Jubilant Cadista Pharmaceuticals Inc.); the hydromorphone FDA label on DailyMed (effective May 14, 2026, Rhodes Pharmaceuticals LLC).
What does the cyclobenzaprine label say about hydromorphone?
Cyclobenzaprine's label (effective February 21, 2025) and its 2 other brand-application labels do not name hydromorphone in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Cyclobenzaprine Hydrochloride), Jubilant Cadista Pharmaceuticals Inc., effective February 21, 2025 (SPL set 592871f6-0eb2-4624-9e10-bd8bf767c002), via openFDA; the full label on DailyMed
What does the hydromorphone label say about cyclobenzaprine?
Hydromorphone label, drug interactionsSerotonergic Drugs Clinical Impact: The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. … 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).
Source: FDA drug label (Hydromorphone Hydrochloride, NDA019034), Fresenius Kabi USA, LLC, effective July 15, 2026 (SPL set e034eb96-03e0-46e1-8b92-5e1f94555e7b), via openFDA
Source: FDA drug label (Hydromorphone Hydrochloride), Rhodes Pharmaceuticals LLC, effective May 14, 2026 (SPL set 37565441-0d95-4743-a695-d7b3326f58a1), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Cyclobenzaprine | Hydromorphone | |
|---|---|---|
| Labeled for | Muscle spasms and spasticity, Nerve pain and fibromyalgia | Pain |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $0.0171 per tablet 10 mg tablet | $0.219 per tablet 4 mg tablet |
| Shortage now | No current entry | In shortage |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once