What the FDA labels say about taking them together
Cyclobenzaprine and naloxone/pentazocine
Naloxone/pentazocine's FDA label of August 28, 2025 names cyclobenzaprine in its drug interactions section; the cyclobenzaprine labels PlainMeds reads (3) do not name naloxone/pentazocine. The naloxone/pentazocine label: “Serotonergic Drugs The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system, such as selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake …”
Check it at the source: the cyclobenzaprine FDA label on DailyMed (effective February 21, 2025, Jubilant Cadista Pharmaceuticals Inc.); the naloxone/pentazocine FDA label on DailyMed (effective August 28, 2025, Lupin Pharmaceuticals,Inc.).
What does the cyclobenzaprine label say about naloxone/pentazocine?
Cyclobenzaprine's label (effective February 21, 2025) and its 2 other brand-application labels do not name naloxone/pentazocine 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 naloxone/pentazocine label say about cyclobenzaprine?
Naloxone/pentazocine label, drug interactionsSerotonergic Drugs The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system, such as selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), triptans, 5-HT3 receptor antagonists, drugs that affect 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), has resulted in serotonin syndrome. [see PRECAUTIONS;
Source: FDA drug label (PENTAZOCINE HYDROCHLORIDE AND NALOXONE HYDROCHLORIDE), Lupin Pharmaceuticals,Inc., effective August 28, 2025 (SPL set 017ef042-40aa-44c9-baa8-037f06356845), 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 | Naloxone/pentazocine | |
|---|---|---|
| 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 | $2.06 per tablet Pentazocine-naloxone 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