What the FDA labels say about taking them together
Isocarboxazid and phenelzine
Isocarboxazid's FDA label of April 21, 2026 names phenelzine in its contraindications section, and phenelzine's label names isocarboxazid too.
Check it at the source: the isocarboxazid FDA label on DailyMed (effective April 21, 2026, Lifsa Drugs LLC); the phenelzine FDA label on DailyMed (effective June 6, 2025, Parke-Davis Div of Pfizer Inc).
What does the isocarboxazid label say about phenelzine?
Isocarboxazid label, contraindicationsGeneric Name: Phenelzine sulfate; Trademark (Manufacturer): Nardil ® (Parke-Davis)
Source: FDA drug label (MARPLAN), Lifsa Drugs LLC, effective April 21, 2026 (SPL set 95fde749-44ad-4668-86c4-0ff17bca0074), via openFDA; the full label on DailyMed
What does the phenelzine label say about isocarboxazid?
Phenelzine label, contraindicationsA List of MAO Inhibitors by Generic Name Follows: pargyline hydrochloride pargyline hydrochloride and methylclothiazide furazolidone isocarboxazid procarbazine tranylcypromine NARDIL should also not be used in combination with buspirone HCl, since several cases of elevated blood pressure have been reported in patients taking MAO inhibitors who were then given buspirone HCl.
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
| Isocarboxazid | Phenelzine | |
|---|---|---|
| Labeled for | Depression | n/a |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | n/a | $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