adorable baby smiling with joy

Peds Calc

Safety Information

Diphenhydramine Contraindications & InteractionsWhen Not to Use & Important Drug Interactions

Screen for interacting drugs and conditions that increase sedation or anticholinergic burden.

Clinical Utility: 8/10
2 Clinical Sources
Back to Diphenhydramine Overview

Absolute: hypersensitivity and MAOI use. Relative: young children for cough/cold combinations, narrow‑angle glaucoma, severe lower respiratory disease, urinary retention/BPH, and concomitant sedatives.

Contraindications

Absolute Contraindications (Never Use)

Concurrent MAO inhibitor use

Contraindicated use due to severe interaction risk

Why: MAOI activity potentiates unpredictable CNS/autonomic effects

Alternative Options:
Consult clinician:Find non‑interacting option

Allergy to diphenhydramine or ethanolamine antihistamines

Risk of anaphylaxis or severe reactions

Why: IgE‑mediated or non‑IgE hypersensitivity

Alternative Options:
Non‑sedating antihistamines:Different class with less cross‑reactivity

Relative Contraindications (Use With Caution)

Routine use for cough/cold in young children

Avoid OTC combination products

Pregnancy & Lactation

Discuss use with a healthcare provider during pregnancy or breastfeeding; avoid as a sleep aid in young children.

Clinical References

Diphenhydramine – Drug Information•MedlinePlus (2024)expert consensusPediatric data
OTC Cough and Cold Medicines in Children•FDA (2024)guidelinePediatric data