What the FDA labels say about taking them together
Linezolid and methadone
Methadone's FDA label of December 8, 2025 names linezolid in its drug interactions section; linezolid's label does not name methadone itself but warns about its class (Opioids (opioid agonists)). The methadone 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 methadone FDA label on DailyMed (effective December 8, 2025, Epic Pharma, LLC).
What does the linezolid label say about methadone?
Linezolid's label does not name methadone 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 methadone label say about linezolid?
Methadone 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).
Methadone label, warnings and precautionsSerotonergic drugs include selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), triptans, 5-HT3 receptor antagonists, drugs that affect the serotonergic neurotransmitter system (e.g., mirtazapine, trazodone, tramadol), certain muscle relaxants (i.e., cyclobenzaprine, metaxalone), and drugs that impair metabolism of serotonin (including MAO inhibitors, both those intended to treat psychiatric disorders and also others, such as linezolid and intravenous methylene blue) [see Drug Interactions (7) ].
Diskets label (Hikma Pharmaceuticals USA Inc., December 1, 2025), 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 (Diskets, NDA017058), Hikma Pharmaceuticals USA Inc., effective December 1, 2025 (SPL set e6af84de-cbfc-4a3b-bd73-6bcf77337168), via openFDA
Source: FDA drug label (Methadone Hydrochloride, NDA021624), Mylan Institutional LLC, effective December 31, 2025 (SPL set 092d78eb-6423-495c-bf0d-e6532bea7138), via openFDA
Source: FDA drug label (Methadone Hydrochloride), Epic Pharma, LLC, effective December 8, 2025 (SPL set 6da7501b-b881-4bc7-891a-74214a00a3ac), 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 | Methadone | |
|---|---|---|
| Labeled for | Bacterial infections | Pain, Opioid use disorder |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $1.44 per tablet 600 mg tablet | $0.177 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