Promethazine and Epinephrine Interaction
Drug interaction information between Promethazine and Epinephrine.
Promethazine and Epinephrine have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Promethazine and Epinephrine. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.
How They Interact
Promethazine can block the way epinephrine normally raises blood pressure, which might cause blood pressure to drop even lower.
FDA Label Information
Epinephrine - Because of the potential for promethazine HCl to reverse epinephrine's vasopressor effect, epinephrine should NOT be used to treat hypotension associated with Promethazine HCl Suppositories overdose.
Promethazine Also Interacts With
- Famciclovir minor
- Zaleplon minor
Epinephrine Also Interacts With
- Tranylcypromine major
- Carbidopa/Levodopa moderate
- Digoxin moderate
- Imipramine moderate
- Levothyroxine minor
Frequently Asked Questions
What SPL severity band is on file for Promethazine + Epinephrine?
Compiled FDA labeling labels this pair minor. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Epinephrine has 28 labeled pairs on file vs Promethazine's 3. In the minor band specifically: Promethazine has 3 (also Famciclovir, Zaleplon); Epinephrine has 24 (also Levothyroxine, Clonidine, Theophylline, Oxytocin).
What mechanism field is on file for Promethazine and Epinephrine?
Promethazine can block the way epinephrine normally raises blood pressure, which might cause blood pressure to drop even lower.
Epinephrine carries more major-labeled pairs than Promethazine
SPL source-record counts only. This page's band is minor · classes on file: Promethazine (Phenothiazine Antiemetic / Antihistamine); Epinephrine (Adrenergic Agonist).
Epinephrine has 1 major-labeled pair vs Promethazine's 0. This page itself is in the minor band, not the major band.
0 major · 0 moderate · 3 minor · 3 total
- Other minor peers for Promethazine
- Famciclovir
- Zaleplon
1 major · 3 moderate · 24 minor · 28 total
- Other minor peers for Epinephrine
- Levothyroxine
- Clonidine
- Theophylline
- Oxytocin
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. This registry does not provide individual medication-combination directions.
Read our methodology - how this data is sourced, computed, and verified.