Drug interactions
Diltiazem + Midazolam
Severity: Major
Diltiazem and Midazolam: major interaction.
Last updated Sources: US FDA label
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 substantially increases midazolam exposure and prolongs its half-life. This leads to deeper and longer sedation and possible respiratory depression.
What this interaction means in plain words
Diltiazem and Midazolam can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Diltiazem belongs to Cardiovascular; Midazolam belongs to Central Nervous System.
Why it happens
Inhibition of CYP3A4 reduces midazolam first-pass and systemic clearance.
What to do
Use a lower midazolam dose and monitor sedation level and respiratory status for a longer period. Consider a benzodiazepine not metabolized by CYP3A4, such as lorazepam.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Diltiazem
- Diltiazem + Flibanserin Contraindicated
- Diltiazem + Ivabradine Contraindicated
- Diltiazem + Lomitapide Contraindicated
- Diltiazem + Lonafarnib Contraindicated
- Acebutolol + Diltiazem Major
- Alfentanil + Diltiazem Major
Other interactions of Midazolam
- Atazanavir + Midazolam Contraindicated
- Cobicistat + Midazolam Contraindicated
- Darunavir + Midazolam Contraindicated
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Midazolam Contraindicated
- Fosamprenavir + Midazolam Contraindicated
- Indinavir + Midazolam Contraindicated
Frequently asked questions
Can I take Diltiazem with Midazolam?
MediHelp rates the interaction as major. Diltiazem and Midazolam can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Diltiazem substantially increases midazolam exposure and prolongs its half-life. This leads to deeper and longer sedation and possible respiratory depression.
How serious is the interaction between Diltiazem and Midazolam?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use a lower midazolam dose and monitor sedation level and respiratory status for a longer period. Consider a benzodiazepine not metabolized by CYP3A4, such as lorazepam.
What other medicines interact with Diltiazem?
MediHelp also lists interactions of Diltiazem with, for example, Flibanserin, Ivabradine, Lomitapide. The full list is on the Diltiazem page.
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