What the FDA labels say about taking them together
Linezolid and morphine
Morphine's FDA label of July 13, 2026 names linezolid in its drug interactions section; linezolid's label does not name morphine itself but warns about its class (Opioids (opioid agonists)). The morphine 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 linezolid FDA label on DailyMed (effective June 19, 2026, Hospira, Inc.); the morphine FDA label on DailyMed (effective July 13, 2026, Bryant Ranch Prepack).
What does the linezolid label say about morphine?
Linezolid's label does not name morphine itself; it warns about its class (Opioids (opioid agonists)):
Linezolid label, warnings and precautionsSpontaneous reports of serotonin syndrome including fatal cases associated with the concomitant use of linezolid and serotonergic agents have been reported. Commonly used serotonergic agents include serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, tricyclic antidepressants, buspirone, serotonin 5-HT1 receptor agonists (triptans), and opioids, including meperidine.
Linezolid label, warnings and precautionsSpontaneous reports of serotonin syndrome including fatal cases associated with the concomitant use of ZYVOX and serotonergic agents have been reported. Commonly used serotonergic agents include serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, tricyclic antidepressants, buspirone, serotonin 5‑HT1 receptor agonists (triptans), and opioids, including meperidine.
Source: FDA drug label (Linezolid), Hospira, Inc., effective June 19, 2026 (SPL set c401f1a8-cc37-461b-bfef-f2e156629bf8), via openFDA; the full label on DailyMed
What does the morphine label say about linezolid?
Morphine 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. … monoamine oxidase (MAO) inhibitors (those intended to treat psychiatric disorders and also others, such as linezolid and intravenous methylene blue).
Source: FDA drug label (Ms Contin, NDA019516), Rhodes Pharmaceuticals LLC, effective August 14, 2026 (SPL set c354b3bf-86c0-4bb8-8b1f-be2164942698), via openFDA
Source: FDA drug label (Morphine sulfate), ANDA078761 (Sun Pharm Inds Ltd), as published by Bryant Ranch Prepack, effective July 13, 2026 (SPL set 595243fe-a4b1-479a-99d6-a084a4181891), 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
| Linezolid | Morphine | |
|---|---|---|
| Labeled for | Bacterial infections | Pain |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $1.44 per tablet 600 mg tablet | $0.226 per tablet 15 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