Drug interactions
Diltiazem + Metformin
Severity: Minor
Diltiazem and Metformin: minor 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
Calcium channel blockers can slightly impair glucose tolerance, and diltiazem may modestly reduce the glucose-lowering effect of metformin. The effect is usually small.
What this interaction means in plain words
Diltiazem and Metformin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Diltiazem belongs to Cardiovascular; Metformin belongs to Endocrine.
Why it happens
Diltiazem may inhibit renal tubular transport and reduce insulin secretion, but the mechanism is not well established.
What to do
Monitor blood glucose when starting or stopping diltiazem and adjust metformin if needed.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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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 Metformin
Frequently asked questions
Can I take Diltiazem with Metformin?
MediHelp rates the interaction as minor. Diltiazem and Metformin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Calcium channel blockers can slightly impair glucose tolerance, and diltiazem may modestly reduce the glucose-lowering effect of metformin. The effect is usually small.
How serious is the interaction between Diltiazem and Metformin?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor blood glucose when starting or stopping diltiazem and adjust metformin if needed.
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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