Drug interactions
Elvitegravir / cobicistat / emtricitabine / tenofovir df + Valacyclovir
Severity: Moderate
Elvitegravir / cobicistat / emtricitabine / tenofovir df and Valacyclovir: 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
Acyclovir, formed from valacyclovir, emtricitabine and tenofovir are all cleared by renal filtration and tubular secretion. Co-administration can raise levels of each and tenofovir adds nephrotoxic potential.
What this interaction means in plain words
Elvitegravir / cobicistat / emtricitabine / tenofovir df and Valacyclovir 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.
Why it happens
Competition for renal tubular secretion plus additive nephrotoxicity, and cobicistat further reduces tubular creatinine secretion.
What to do
Monitor serum creatinine, phosphate and urinalysis regularly. Adjust the valacyclovir dose to renal function and stop the combination if renal function worsens.
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 Valacyclovir
Frequently asked questions
Can I take Elvitegravir / cobicistat / emtricitabine / tenofovir df with Valacyclovir?
MediHelp rates the interaction as moderate. Elvitegravir / cobicistat / emtricitabine / tenofovir df and Valacyclovir 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. Acyclovir, formed from valacyclovir, emtricitabine and tenofovir are all cleared by renal filtration and tubular secretion. Co-administration can raise levels of each and tenofovir adds nephrotoxic potential.
How serious is the interaction between Elvitegravir / cobicistat / emtricitabine / tenofovir df and Valacyclovir?
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 serum creatinine, phosphate and urinalysis regularly. Adjust the valacyclovir dose to renal function and stop the combination if renal function worsens.
What other medicines interact with Valacyclovir?
MediHelp also lists interactions of Valacyclovir with, for example, Talimogene laherparepvec, Bacitracin, Cilastatin-imipenem. The full list is on the Valacyclovir page.
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