Drug interactions
Diltiazem + Itraconazole
Severity: Major
Diltiazem and Itraconazole: 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
Itraconazole and diltiazem inhibit each other's CYP3A4 metabolism, raising concentrations of both drugs. Additive negative inotropic and chronotropic effects may cause bradycardia, hypotension, AV block or worsening heart failure.
What this interaction means in plain words
Diltiazem and Itraconazole 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; Itraconazole belongs to Anti Fungals.
Why it happens
Mutual CYP3A4 inhibition combined with additive negative inotropic and conduction effects.
What to do
Monitor heart rate, blood pressure and ECG, and reduce the diltiazem dose if needed. Avoid in patients with heart failure or conduction disease, and consider a different antifungal.
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 Itraconazole
- Alfuzosin + Itraconazole Contraindicated
- Alprazolam + Itraconazole Contraindicated
- Avanafil + Itraconazole Contraindicated
- Conivaptan + Itraconazole Contraindicated
- Dihydroergotamine intranasal + Itraconazole Contraindicated
- Dihydroergotamine + Itraconazole Contraindicated
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 Diltiazem with Itraconazole?
MediHelp rates the interaction as major. Diltiazem and Itraconazole 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. Itraconazole and diltiazem inhibit each other's CYP3A4 metabolism, raising concentrations of both drugs. Additive negative inotropic and chronotropic effects may cause bradycardia, hypotension, AV block or worsening heart failure.
How serious is the interaction between Diltiazem and Itraconazole?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor heart rate, blood pressure and ECG, and reduce the diltiazem dose if needed. Avoid in patients with heart failure or conduction disease, and consider a different antifungal.
What other medicines interact with Itraconazole?
MediHelp also lists interactions of Itraconazole with, for example, Alfuzosin, Alprazolam, Avanafil. The full list is on the Itraconazole page.
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