Drug interactions
Chlordiazepoxide + Diphenhydramine
Severity: Moderate
Chlordiazepoxide 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
Diphenhydramine is a strongly sedating, anticholinergic antihistamine, and with a benzodiazepine it can cause pronounced drowsiness and psychomotor impairment. Older adults may develop confusion, falls and delirium.
What this interaction means in plain words
Chlordiazepoxide 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.
Chlordiazepoxide belongs to Central Nervous System; Diphenhydramine belongs to Respiratory.
Why it happens
Additive CNS depression via central H1 antagonism and GABA-A enhancement.
What to do
Avoid combined use for sleep in older adults and use the lowest doses otherwise. Counsel patients on avoiding driving and alcohol.
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 Chlordiazepoxide
Other interactions of Diphenhydramine
Frequently asked questions
Can I take Chlordiazepoxide with Diphenhydramine?
MediHelp rates the interaction as moderate. Chlordiazepoxide 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. Diphenhydramine is a strongly sedating, anticholinergic antihistamine, and with a benzodiazepine it can cause pronounced drowsiness and psychomotor impairment. Older adults may develop confusion, falls and delirium.
How serious is the interaction between Chlordiazepoxide 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 combined use for sleep in older adults and use the lowest doses otherwise. Counsel patients on avoiding driving and alcohol.
What other medicines interact with Chlordiazepoxide?
MediHelp also lists interactions of Chlordiazepoxide with, for example, Alfentanil, Alprazolam, Amobarbital. The full list is on the Chlordiazepoxide page.
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