What the FDA labels say about taking them together
Hydromorphone and phenelzine
Hydromorphone's FDA label of May 14, 2026 names phenelzine in its drug interactions section; the phenelzine label PlainMeds reads does not name hydromorphone. The hydromorphone label: “MAOI interactions with opioids may manifest as serotonin syndrome or opioid toxicity.”
Check it at the source: the hydromorphone FDA label on DailyMed (effective May 14, 2026, Rhodes Pharmaceuticals LLC); the phenelzine FDA label on DailyMed (effective June 6, 2025, Parke-Davis Div of Pfizer Inc).
What does the hydromorphone label say about phenelzine?
Hydromorphone label, drug interactionsMonoamine Oxidase Inhibitors (MAOIs) Clinical Impact: MAOI interactions with opioids may manifest as serotonin syndrome or opioid toxicity (…). If urgent use of an opioid is necessary, use test doses and frequent titration of small doses to treat pain while closely monitoring blood pressure and signs and symptoms of CNS and respiratory depression. Intervention: The use of hydromorphone hydrochloride oral solution or hydromorphone hydrochloride tablets is not recommended for patients taking MAOIs or within 14 days of stopping such treatment. Examples: Phenelzine, tranylcypromine, and linezolid.
Hydromorphone Hydrochloride label (Hospira, Inc., February 4, 2026), drug interactionsMonoamine Oxidase Inhibitors (MAOIs) Clinical Impact: MAOI interactions with opioids may manifest as serotonin syndrome or opioid toxicity (…). … while closely monitoring blood pressure and signs and symptoms of CNS and respiratory depression. Examples: phenelzine, tranylcypromine, linezolid
Source: FDA drug label (Hydromorphone Hydrochloride, NDA019034), Fresenius Kabi USA, LLC, effective July 15, 2026 (SPL set e034eb96-03e0-46e1-8b92-5e1f94555e7b), via openFDA
Source: FDA drug label (Hydromorphone Hydrochloride, NDA200403), Hospira, Inc., effective February 4, 2026 (SPL set f9ca2ef5-46d8-475a-a26e-f7c8becd6db7), via openFDA
Source: FDA drug label (Hydromorphone Hydrochloride), Rhodes Pharmaceuticals LLC, effective May 14, 2026 (SPL set 37565441-0d95-4743-a695-d7b3326f58a1), via openFDA; the full label on DailyMed
What does the phenelzine label say about hydromorphone?
Phenelzine's label (effective June 6, 2025) does not name hydromorphone in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Nardil), Parke-Davis Div of Pfizer Inc, effective June 6, 2025 (SPL set 513a41d0-37d4-4355-8a6d-a2c643bce6fa), 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
| Hydromorphone | Phenelzine | |
|---|---|---|
| Labeled for | Pain | n/a |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.219 per tablet 4 mg tablet | $0.586 per tablet 15 mg tablet |
| Shortage now | In shortage | 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