Drug interactions
Diltiazem + Mefloquine
Severity: Moderate
Diltiazem and Mefloquine: 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 is a moderate CYP3A4 inhibitor and can raise mefloquine concentrations, while both drugs affect cardiac conduction. The combination may add to bradycardia, AV block or QT-related arrhythmia.
What this interaction means in plain words
Diltiazem and Mefloquine 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 belongs to Cardiovascular; Mefloquine belongs to Anti Parasitic.
Why it happens
CYP3A4 inhibition by diltiazem reduces mefloquine clearance, combined with additive effects on cardiac conduction.
What to do
Monitor heart rate, PR interval and ECG, and watch for mefloquine neuropsychiatric effects. Consider another antimalarial in patients with conduction disease.
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 Mefloquine
- Arsenic trioxide + Mefloquine Contraindicated
- Dronedarone + Mefloquine Contraindicated
- Ibutilide + Mefloquine Contraindicated
- Levoketoconazole + Mefloquine Contraindicated
- Mefloquine + Nilotinib Contraindicated
- Mefloquine + Pimozide 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 Mefloquine?
MediHelp rates the interaction as moderate. Diltiazem and Mefloquine 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 is a moderate CYP3A4 inhibitor and can raise mefloquine concentrations, while both drugs affect cardiac conduction. The combination may add to bradycardia, AV block or QT-related arrhythmia.
How serious is the interaction between Diltiazem and Mefloquine?
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 heart rate, PR interval and ECG, and watch for mefloquine neuropsychiatric effects. Consider another antimalarial in patients with conduction disease.
What other medicines interact with Mefloquine?
MediHelp also lists interactions of Mefloquine with, for example, Arsenic trioxide, Dronedarone, Ibutilide. The full list is on the Mefloquine page.
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