What the FDA labels say about taking them together
Diphenhydramine and epinephrine
Epinephrine's FDA label (Epipen) of February 15, 2023 names diphenhydramine in its drug interactions section; the diphenhydramine label PlainMeds reads does not name epinephrine.
Check it at the source: the diphenhydramine FDA label on DailyMed (effective November 18, 2025, Heritage Pharmaceuticals Inc. d/b/a Avet Pharmaceuticals Inc.); the epinephrine FDA label on DailyMed (effective July 13, 2026, A-S Medication Solutions).
What does the diphenhydramine label say about epinephrine?
Diphenhydramine's label (effective November 18, 2025) does not name epinephrine in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Diphenhydramine Hydrochloride), Heritage Pharmaceuticals Inc. d/b/a Avet Pharmaceuticals Inc., effective November 18, 2025 (SPL set 6178d3a1-0741-49a4-be81-c4f7d29f8b2a), via openFDA; the full label on DailyMed
What does the epinephrine label say about diphenhydramine?
Epipen label (Viatris Specialty LLC, February 15, 2023), drug interactionsAntidepressants, Monoamine Oxidase Inhibitors, Levothyroxine, and Antihistamines The effects of epinephrine may be potentiated by tricyclic antidepressants, monoamine oxidase inhibitors, levothyroxine sodium, and certain antihistamines, notably chlorpheniramine, tripelennamine, and diphenhydramine.
Source: FDA drug label (Epipen, NDA019430), Viatris Specialty LLC, effective February 15, 2023 (SPL set 7560c201-9246-487c-a13b-6295db04274a), via openFDA
Source: FDA drug label (Epinephrine), A-S Medication Solutions, effective July 13, 2026 (SPL set 6e811e28-0199-4df7-a916-5940c632401d), 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
| Diphenhydramine | Epinephrine | |
|---|---|---|
| Labeled for | Cough and cold, Allergies, Pain | Asthma |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.898 per mL 50 mg/mL vial | $123.51 per unit 0.15 mg auto-injct |
| Shortage now | No current entry | A presentation being discontinued |
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