What the FDA labels say about taking them together
Duloxetine and fentanyl
Duloxetine's FDA label of May 14, 2024 names fentanyl in its warnings and precautions section; fentanyl's label does not name duloxetine itself but warns about its class (SNRIs (serotonin and norepinephrine reuptake inhibitors)). The duloxetine label: “The risk is increased with concomitant use of other serotonergic drugs and with drugs that impair metabolism of serotonin.”
Check it at the source: the duloxetine FDA label on DailyMed (effective May 14, 2024, SUN PHARMACEUTICAL INDUSTRIES, INC.); the fentanyl FDA label on DailyMed (effective March 6, 2026, Hikma Pharmaceuticals USA Inc.).
What does the duloxetine label say about fentanyl?
Duloxetine label, warnings and precautionsThe risk is increased with concomitant use of other serotonergic drugs (including triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, meperidine, methadone, tryptophan, buspirone, amphetamines, and St. John’s Wort) and with drugs that impair metabolism of serotonin [see Contraindications (4), Drug Interactions (7)].
Source: FDA drug label (Duloxetine, NDA219131), Almatica Pharma LLC, effective March 2, 2026 (SPL set bb2ca3bf-983c-1e4a-a91d-dc7dee66d741), via openFDA
Source: FDA drug label (DRIZALMA SPRINKLE), SUN PHARMACEUTICAL INDUSTRIES, INC., effective May 14, 2024 (SPL set b41423b8-dfec-4d79-ba3c-e43a87803d85), via openFDA; the full label on DailyMed
What does the fentanyl label say about duloxetine?
Fentanyl's label does not name duloxetine itself; it warns about its class (SNRIs (serotonin and norepinephrine reuptake inhibitors)):
Fentanyl label, warnings and precautionsIf a patient is suspected to be experiencing OIH, carefully consider appropriately decreasing the dose of the current opioid analgesic or opioid rotation (safely switching the patient to a different opioid moiety) [see Dosage and Administration (2), Warnings and Precautions (5.7) ] . 5.8 Serotonin Syndrome with Concomitant Use of Serotonergic Drugs Cases of serotonin syndrome, a potentially life-threatening condition, have been reported during concomitant use of fentanyl with serotonergic drugs. …
Fentanyl label, warnings and precautionsSyndrome with Concomitant Use of Serotonergic Drugs Cases of serotonin syndrome, a potentially life-threatening condition, have been reported during concomitant use of fentanyl with serotonergic drugs. Serotonergic 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, trazadone, tramadol), certain …
Source: FDA drug label (Fentanyl Citrate), Hikma Pharmaceuticals USA Inc., effective March 6, 2026 (SPL set ce5db1c2-feb1-4ad2-847a-d02e865bd47e), 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
| Duloxetine | Fentanyl | |
|---|---|---|
| Labeled for | Depression, Anxiety, Nerve pain and fibromyalgia, Pain | Pain |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.102 per capsule 30 mg capsule | $1.79 per mL 100 mcg/2 mL vial |
| 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