What the FDA labels say about taking them together
Levorphanol and mirtazapine
Levorphanol's FDA label of January 13, 2026 names mirtazapine in its drug interactions section; the mirtazapine label PlainMeds reads does not name levorphanol. The levorphanol 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 levorphanol FDA label on DailyMed (effective January 13, 2026, Sun Pharmaceutical Industries, Inc.); the mirtazapine FDA label on DailyMed (effective August 6, 2025, Organon LLC).
What does the levorphanol label say about mirtazapine?
Levorphanol 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), and 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 (Levorphanol Tartrate), Sun Pharmaceutical Industries, Inc., effective January 13, 2026 (SPL set 438cf3ea-04fe-4626-9f0f-adcda7633651), via openFDA; the full label on DailyMed
What does the mirtazapine label say about levorphanol?
Mirtazapine's label (effective August 6, 2025) does not name levorphanol in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (REMERON), Organon LLC, effective August 6, 2025 (SPL set 98ad1917-a094-44f5-a28f-a64a8cfcd887), 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
| Levorphanol | Mirtazapine | |
|---|---|---|
| Labeled for | Pain | Depression |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $10.65 per tablet 2 mg tablet | $0.063 per tablet 15 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