What the FDA labels say about taking them together
Metyrosine and phentolamine
Metyrosine's FDA label of July 1, 2021 names phentolamine in its warnings section; the phentolamine labels PlainMeds reads (2) do not name metyrosine. The metyrosine label: “… during manipulation of the tumor, and the alpha-adrenergic blocking drug, phentolamine, may be needed.”
Check it at the source: the metyrosine FDA label on DailyMed (effective July 1, 2021, Bausch Health US, LLC); the phentolamine FDA label on DailyMed (effective March 15, 2026, Oyster Point Pharma, Inc.).
What does the metyrosine label say about phentolamine?
Metyrosine label, warningsIntraoperative Effects While the preoperative use of DEMSER in patients with pheochromocytoma is thought to decrease intraoperative problems with blood pressure control, DEMSER does not eliminate the danger of hypertensive crises or arrhythmias during manipulation of the tumor, and the alpha-adrenergic blocking drug, phentolamine, may be needed.
Source: FDA drug label (Demser), Bausch Health US, LLC, effective July 1, 2021 (SPL set 32fb2f2f-34b5-4cd5-9145-c3ab37c5ca92), via openFDA; the full label on DailyMed
What does the phentolamine label say about metyrosine?
Phentolamine's label (effective March 15, 2026) and its 1 other brand-application label do not name metyrosine 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
| Metyrosine | Phentolamine | |
|---|---|---|
| Labeled for | n/a | n/a |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | n/a | n/a |
| Shortage now | No current entry | 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