What the FDA labels say about taking them together
Meperidine and phenelzine
Meperidine's FDA label of November 29, 2025 names phenelzine in its drug interactions section, and phenelzine's label names meperidine too. The meperidine label: “Meperidine is contraindicated in patients who are receiving monoamine oxidase (MAOIs) or those who have recently received such agents. …”
Check it at the source: the meperidine FDA label on DailyMed (effective November 29, 2025, EPIC PHARMA, LLC); the phenelzine FDA label on DailyMed (effective June 6, 2025, Parke-Davis Div of Pfizer Inc).
What does the meperidine label say about phenelzine?
Meperidine label, drug interactionsMonoamine Oxidase Inhibitors (MAOIs) Clinical Impact: Meperidine is contraindicated in patients who are receiving monoamine oxidase (MAOIs) or those who have recently received such agents. Therapeutic doses of meperidine have occasionally precipitated unpredictable, severe, and occasionally fatal reactions in patients who have received such agents within 14 days. … usefulness and safety of narcotic antagonists in the treatment of these reactions is unknown.) Examples: phenelzine, tranylcypromine, linezolid
Source: FDA drug label (Demerol, NDA021171), Hospira, Inc., effective July 20, 2026 (SPL set b31d1308-28c3-43f4-e0a6-2f3ed76b8975), via openFDA
Source: FDA drug label (Meperidine Hydrochloride), EPIC PHARMA, LLC, effective November 29, 2025 (SPL set fae5cc34-5917-4445-9516-25f97ffca8db), via openFDA; the full label on DailyMed
What does the phenelzine label say about meperidine?
Phenelzine label, contraindicationsConcomitant use with meperidine is contraindicated (see WARNINGS ).
Phenelzine label, warningsPatients should be warned that the use of the above foods, beverages, or medications may cause a reaction characterized by headache and other serious symptoms due to a rise in blood pressure, with the exception of dextromethorphan which may cause reactions similar to those seen with meperidine.
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
| Meperidine | Phenelzine | |
|---|---|---|
| Labeled for | Pain | n/a |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.157 per mL 50 mg/5 mL solution | $0.586 per tablet 15 mg tablet |
| Shortage now | Listed; available | 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