Drug interactions
Dexchlorpheniramine + Diphenhydramine
Severity: Moderate
Dexchlorpheniramine and Diphenhydramine: moderate 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
Both are first-generation antihistamines with sedating and anticholinergic effects. Taking them together duplicates therapy and increases drowsiness, dry mouth, urinary retention, blurred vision and confusion. Older adults and young children are at higher risk.
What this interaction means in plain words
Dexchlorpheniramine and Diphenhydramine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Dexchlorpheniramine belongs to Respiratory; Diphenhydramine belongs to Respiratory.
Why it happens
Additive central H1 receptor blockade and additive antimuscarinic effects.
What to do
Avoid combining two sedating antihistamines and use a single agent at the lowest effective dose. Check combination cold and sleep products for hidden duplication.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Diphenhydramine
Other interactions of Dexchlorpheniramine
- Alprazolam + Dexchlorpheniramine Moderate
- Amisulpride + Dexchlorpheniramine Moderate
- Amitriptyline + Dexchlorpheniramine Moderate
- Amobarbital + Dexchlorpheniramine Moderate
- Asenapine + Dexchlorpheniramine Moderate
- Azelastine-fluticasone + Dexchlorpheniramine Moderate
Frequently asked questions
Can I take Dexchlorpheniramine with Diphenhydramine?
MediHelp rates the interaction as moderate. Dexchlorpheniramine and Diphenhydramine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Both are first-generation antihistamines with sedating and anticholinergic effects. Taking them together duplicates therapy and increases drowsiness, dry mouth, urinary retention, blurred vision and confusion. Older adults and young children are at higher risk.
How serious is the interaction between Dexchlorpheniramine and Diphenhydramine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid combining two sedating antihistamines and use a single agent at the lowest effective dose. Check combination cold and sleep products for hidden duplication.
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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