Drug interactions
Diltiazem + Lithium
Severity: Moderate
Diltiazem and Lithium: 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
Case reports describe lithium neurotoxicity, including confusion, tremor and ataxia, with diltiazem despite normal serum lithium levels, and bradycardia may also occur. The risk is unpredictable.
What this interaction means in plain words
Diltiazem and Lithium 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; Lithium belongs to Central Nervous System.
Why it happens
Mechanism is not well established; possible enhanced central effects of lithium and additive cardiac conduction effects.
What to do
Monitor for neurological symptoms and bradycardia, and check lithium levels when starting diltiazem. Stop one drug if neurotoxicity appears.
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 Diltiazem
- Diltiazem + Flibanserin Contraindicated
- Diltiazem + Ivabradine Contraindicated
- Diltiazem + Lomitapide Contraindicated
- Diltiazem + Lonafarnib Contraindicated
- Acebutolol + Diltiazem Major
- Alfentanil + Diltiazem Major
Other interactions of Lithium
- Lithium + Thioridazine Contraindicated
- Lithium + Vandetanib Contraindicated
- Aceclofenac + Lithium Major
- Acemetacin + Lithium Major
- Amisulpride + Lithium Major
- Amlodipine-benazepril + Lithium Major
Frequently asked questions
Can I take Diltiazem with Lithium?
MediHelp rates the interaction as moderate. Diltiazem and Lithium 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. Case reports describe lithium neurotoxicity, including confusion, tremor and ataxia, with diltiazem despite normal serum lithium levels, and bradycardia may also occur. The risk is unpredictable.
How serious is the interaction between Diltiazem and Lithium?
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 neurological symptoms and bradycardia, and check lithium levels when starting diltiazem. Stop one drug if neurotoxicity appears.
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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