What the FDA labels say about taking them together
Acetaminophen/benzhydrocodone and metaxalone
Acetaminophen/benzhydrocodone's FDA label of January 7, 2025 names metaxalone in its drug interactions section; the metaxalone labels PlainMeds reads (2) do not name acetaminophen/benzhydrocodone. The acetaminophen/benzhydrocodone 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 acetaminophen/benzhydrocodone FDA label on DailyMed (effective January 7, 2025, Zevra Therapeutics, Inc.); the metaxalone FDA label on DailyMed (effective January 11, 2023, Amneal Pharmaceuticals of New York LLC).
What does the acetaminophen/benzhydrocodone label say about metaxalone?
Acetaminophen/benzhydrocodone 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. … 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 (APADAZ), Zevra Therapeutics, Inc., effective January 7, 2025 (SPL set 0590d4e5-7107-4015-a6a8-deac14265aa2), via openFDA; the full label on DailyMed
What does the metaxalone label say about acetaminophen/benzhydrocodone?
Metaxalone's label (effective January 11, 2023) and its 1 other brand-application label do not name acetaminophen/benzhydrocodone in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Metaxalone), Amneal Pharmaceuticals of New York LLC, effective January 11, 2023 (SPL set f06f2b96-3684-483c-89f7-6c9201fd4664), 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
| Acetaminophen/benzhydrocodone | Metaxalone | |
|---|---|---|
| Labeled for | Pain | Muscle spasms and spasticity |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | n/a | $0.452 per tablet 800 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