What the FDA labels say about taking them together
Isocarboxazid and phentolamine
Isocarboxazid's FDA label of April 21, 2026 names phentolamine in its warnings section; the phentolamine labels PlainMeds reads (2) do not name isocarboxazid. The isocarboxazid label: “Although there has been no systematic study of treatment of hypertensive crisis, phentolamine has been used and is recommended at a dosage of 5 mg IV.”
Check it at the source: the isocarboxazid FDA label on DailyMed (effective April 21, 2026, Lifsa Drugs LLC); the phentolamine FDA label on DailyMed (effective March 15, 2026, Oyster Point Pharma, Inc.).
What does the isocarboxazid label say about phentolamine?
Isocarboxazid label, warningsAlthough there has been no systematic study of treatment of hypertensive crisis, phentolamine (available as Regitine ® , Novartis) has been used and is recommended at a dosage of 5 mg IV.
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 phentolamine label say about isocarboxazid?
Phentolamine's label (effective March 15, 2026) and its 1 other brand-application label do not name isocarboxazid in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Ryzumvi), NDA217064 (Famygen Life Sci), as published by Oyster Point Pharma, Inc., effective March 15, 2026 (SPL set 96bb1e53-c2cc-4e60-a21a-db0269c371bf), 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 | Phentolamine | |
|---|---|---|
| Labeled for | Depression | n/a |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | n/a | n/a |
| 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