What the FDA labels say about taking them together
Levorphanol and methylene blue
Levorphanol's FDA label of January 13, 2026 names methylene blue in its drug interactions section; methylene blue's label does not name levorphanol itself but warns about its class (Opioids (opioid agonists)). 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 methylene blue FDA label on DailyMed (effective May 28, 2025, American Regent, Inc.).
What does the levorphanol label say about methylene blue?
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 methylene blue label say about levorphanol?
Methylene blue's label does not name levorphanol itself; it warns about its class (Opioids (opioid agonists)):
Methylene blue label, boxed warningSEROTONIN SYNDROME WITH CONCOMITANT USE OF SEROTONERGIC DRUGS AND OPIOIDS PROVAYBLUE may cause serious or fatal serotonergic syndrome when used in combination with serotonergic drugs and opioids.
Methylene blue label, boxed warningSEROTONIN SYNDROME WITH CONCOMITANT USE OF SEROTONERGIC DRUGS AND OPIOIDS See full prescribing information for complete boxed warning.
Source: FDA drug label (PROVAYBLUE), NDA204630 (Provepharm Sas), as published by American Regent, Inc., effective May 28, 2025 (SPL set 4f6848e5-35ed-4046-b13c-3032b5ba3232), 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 | Methylene blue | |
|---|---|---|
| Labeled for | Pain | n/a |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $10.65 per tablet 2 mg tablet | n/a |
| 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