Drug interactions
Diphenhydramine + Epinephrine
Severity: Minor
Diphenhydramine and Epinephrine: minor interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Diphenhydramine is often given alongside epinephrine in allergic reactions without a harmful interaction. Epinephrine does not meaningfully offset the sedation, and the pair has no established clinically significant interaction. Diphenhydramine should never replace epinephrine in anaphylaxis.
What this interaction means in plain words
Diphenhydramine and Epinephrine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Diphenhydramine belongs to Respiratory; Epinephrine belongs to Endocrine.
Why it happens
No established pharmacokinetic interaction; opposing central and sympathomimetic effects are minor and unpredictable.
What to do
No dose change is required; give epinephrine first in anaphylaxis and monitor heart rate and blood pressure.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Diphenhydramine
Other interactions of Epinephrine
- Epinephrine + Isocarboxazid Contraindicated
- Epinephrine + Phenelzine Contraindicated
- Epinephrine + Tranylcypromine Contraindicated
- Acebutolol + Epinephrine Major
- Amitriptyline + Epinephrine Major
- Amoxapine + Epinephrine Major
Frequently asked questions
Can I take Diphenhydramine with Epinephrine?
MediHelp rates the interaction as minor. Diphenhydramine and Epinephrine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Diphenhydramine is often given alongside epinephrine in allergic reactions without a harmful interaction. Epinephrine does not meaningfully offset the sedation, and the pair has no established clinically significant interaction. Diphenhydramine should never replace epinephrine in anaphylaxis.
How serious is the interaction between Diphenhydramine and Epinephrine?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No dose change is required; give epinephrine first in anaphylaxis and monitor heart rate and blood pressure.
What other medicines interact with Diphenhydramine?
MediHelp also lists interactions of Diphenhydramine with, for example, Alfentanil, Belladonna and opium, Benzhydrocodone / acetaminophen. The full list is on the Diphenhydramine page.
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