Drug interactions
Elvitegravir / cobicistat / emtricitabine / tenofovir df + Tolterodine
Severity: Major
Elvitegravir / cobicistat / emtricitabine / tenofovir df and Tolterodine: major 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
Cobicistat inhibits CYP3A4 and CYP2D6, both involved in tolterodine metabolism, raising tolterodine and its active metabolite exposure. This increases anticholinergic adverse effects and potential QT prolongation.
What this interaction means in plain words
Elvitegravir / cobicistat / emtricitabine / tenofovir df and Tolterodine 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.
Why it happens
Cobicistat inhibits CYP3A4 and CYP2D6, reducing tolterodine clearance.
What to do
Limit tolterodine to 1 mg twice daily (or lower) and monitor for anticholinergic effects, urinary retention and QT-related symptoms.
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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Other interactions of Tolterodine
Frequently asked questions
Can I take Elvitegravir / cobicistat / emtricitabine / tenofovir df with Tolterodine?
MediHelp rates the interaction as major. Elvitegravir / cobicistat / emtricitabine / tenofovir df and Tolterodine 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. Cobicistat inhibits CYP3A4 and CYP2D6, both involved in tolterodine metabolism, raising tolterodine and its active metabolite exposure. This increases anticholinergic adverse effects and potential QT prolongation.
How serious is the interaction between Elvitegravir / cobicistat / emtricitabine / tenofovir df and Tolterodine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Limit tolterodine to 1 mg twice daily (or lower) and monitor for anticholinergic effects, urinary retention and QT-related symptoms.
What other medicines interact with Tolterodine?
MediHelp also lists interactions of Tolterodine with, for example, Clarithromycin, Clozapine, Cobicistat. The full list is on the Tolterodine page.
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