Drug interactions
Diazepam + Diltiazem
Severity: Moderate
Diazepam and Diltiazem: 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
Diltiazem inhibits CYP3A4, which contributes to diazepam clearance, and can raise diazepam concentrations. This may cause excess sedation, psychomotor impairment and prolonged effects, particularly in older adults.
What this interaction means in plain words
Diazepam and Diltiazem 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.
Diazepam belongs to Musculoskeletal; Diltiazem belongs to Cardiovascular.
Why it happens
Diltiazem inhibits CYP3A4-mediated N-demethylation of diazepam, reducing its clearance.
What to do
Monitor for oversedation and consider a lower diazepam dose, especially in elderly patients; choose a non-CYP3A4 benzodiazepine such as lorazepam if problematic.
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 Diazepam
Other interactions of Diltiazem
- Diltiazem + Flibanserin Contraindicated
- Diltiazem + Ivabradine Contraindicated
- Diltiazem + Lomitapide Contraindicated
- Diltiazem + Lonafarnib Contraindicated
- Acebutolol + Diltiazem Major
- Alfentanil + Diltiazem Major
Frequently asked questions
Can I take Diazepam with Diltiazem?
MediHelp rates the interaction as moderate. Diazepam and Diltiazem 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. Diltiazem inhibits CYP3A4, which contributes to diazepam clearance, and can raise diazepam concentrations. This may cause excess sedation, psychomotor impairment and prolonged effects, particularly in older adults.
How serious is the interaction between Diazepam and Diltiazem?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for oversedation and consider a lower diazepam dose, especially in elderly patients; choose a non-CYP3A4 benzodiazepine such as lorazepam if problematic.
What other medicines interact with Diazepam?
MediHelp also lists interactions of Diazepam with, for example, Calcium / magnesium / potassium / sodium oxybates, Alfentanil, Alprazolam. The full list is on the Diazepam page.
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