What the FDA labels say about taking them together
Codeine and cyclobenzaprine
Codeine's FDA label of December 22, 2025 names cyclobenzaprine in its drug interactions section; the cyclobenzaprine labels PlainMeds reads (3) do not name codeine. The codeine 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 codeine FDA label on DailyMed (effective December 22, 2025, Hikma Pharmaceuticals USA Inc.); the cyclobenzaprine FDA label on DailyMed (effective February 21, 2025, Jubilant Cadista Pharmaceuticals Inc.).
What does the codeine label say about cyclobenzaprine?
Codeine 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 (Codeine sulfate), Hikma Pharmaceuticals USA Inc., effective December 22, 2025 (SPL set 010905f9-3bcb-4b50-9fe8-a3ad0010f14c), via openFDA; the full label on DailyMed
What does the cyclobenzaprine label say about codeine?
Cyclobenzaprine's label (effective February 21, 2025) and its 2 other brand-application labels do not name codeine 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
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
| Codeine | Cyclobenzaprine | |
|---|---|---|
| Labeled for | Pain | Muscle spasms and spasticity, Nerve pain and fibromyalgia |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.726 per tablet 30 mg tablet | $0.0171 per tablet 10 mg tablet |
| Shortage now | No current entry | No current entry |
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