Drug interactions
Diltiazem + Fesoterodine
Severity: Minor
Diltiazem and Fesoterodine: 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
Diltiazem is a moderate CYP3A4 inhibitor and can raise exposure to the active metabolite of fesoterodine to a limited extent. This may modestly increase antimuscarinic adverse effects.
What this interaction means in plain words
Diltiazem and Fesoterodine 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; Fesoterodine belongs to Genitourinary.
Why it happens
Diltiazem inhibits CYP3A4, reducing clearance of the active fesoterodine metabolite.
What to do
No fesoterodine dose change is routinely needed; monitor for dry mouth, constipation and urinary retention.
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 Fesoterodine
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 Fesoterodine?
MediHelp rates the interaction as minor. Diltiazem and Fesoterodine 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 is a moderate CYP3A4 inhibitor and can raise exposure to the active metabolite of fesoterodine to a limited extent. This may modestly increase antimuscarinic adverse effects.
How serious is the interaction between Diltiazem and Fesoterodine?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No fesoterodine dose change is routinely needed; monitor for dry mouth, constipation and urinary retention.
What other medicines interact with Fesoterodine?
MediHelp also lists interactions of Fesoterodine with, for example, Bethanechol, Clozapine, Levoketoconazole. The full list is on the Fesoterodine page.
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