Drug interactions
Diphenhydramine + Oxazepam
Severity: Moderate
Diphenhydramine and Oxazepam: 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 drugs cause sedation, so the combination can produce pronounced drowsiness, impaired psychomotor performance and confusion. Older adults are particularly vulnerable to falls and delirium.
What this interaction means in plain words
Diphenhydramine and Oxazepam 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.
Diphenhydramine belongs to Respiratory; Oxazepam belongs to Central Nervous System.
Why it happens
Additive CNS depression from central H1 antagonism and benzodiazepine GABA-A potentiation.
What to do
Avoid combined use for sleep, especially in older adults, and use a non-sedating antihistamine where possible. Counsel on driving and alcohol avoidance.
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 Oxazepam
- Calcium / magnesium / potassium / sodium oxybates + Oxazepam Contraindicated
- Oxazepam + Sodium oxybate Contraindicated
- Alfentanil + Oxazepam Major
- Amobarbital + Oxazepam Major
- Baclofen + Oxazepam Major
- Belladonna and opium + Oxazepam Major
Other interactions of Diphenhydramine
Frequently asked questions
Can I take Diphenhydramine with Oxazepam?
MediHelp rates the interaction as moderate. Diphenhydramine and Oxazepam 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 drugs cause sedation, so the combination can produce pronounced drowsiness, impaired psychomotor performance and confusion. Older adults are particularly vulnerable to falls and delirium.
How serious is the interaction between Diphenhydramine and Oxazepam?
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 combined use for sleep, especially in older adults, and use a non-sedating antihistamine where possible. Counsel on driving and alcohol avoidance.
What other medicines interact with Oxazepam?
MediHelp also lists interactions of Oxazepam with, for example, Calcium / magnesium / potassium / sodium oxybates, Sodium oxybate, Alfentanil. The full list is on the Oxazepam page.
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