Drug interactions
Azelastine + Diphenhydramine
Severity: Moderate
Azelastine 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 antihistamines with sedative potential, and diphenhydramine is strongly sedating and anticholinergic. Together they may cause pronounced drowsiness and impaired psychomotor performance.
What this interaction means in plain words
Azelastine 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.
Azelastine belongs to Respiratory; Diphenhydramine belongs to Respiratory.
Why it happens
Additive H1-antihistamine mediated CNS depression.
What to do
Avoid duplicate antihistamine therapy where possible. If both are used, advise against driving and alcohol and watch for confusion in older adults.
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 Azelastine
Other interactions of Diphenhydramine
Frequently asked questions
Can I take Azelastine with Diphenhydramine?
MediHelp rates the interaction as moderate. Azelastine 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 antihistamines with sedative potential, and diphenhydramine is strongly sedating and anticholinergic. Together they may cause pronounced drowsiness and impaired psychomotor performance.
How serious is the interaction between Azelastine 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 duplicate antihistamine therapy where possible. If both are used, advise against driving and alcohol and watch for confusion in older adults.
What other medicines interact with Azelastine?
MediHelp also lists interactions of Azelastine with, for example, Calcium / magnesium / potassium / sodium oxybates, Methadone, Sodium oxybate. The full list is on the Azelastine page.
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