Drug interactions
Imipenem / cilastatin + Valacyclovir
Severity: Moderate
Imipenem / cilastatin 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
Both drugs can lower the seizure threshold, particularly in renal impairment, so combined use may raise seizure risk. The evidence is limited and largely theoretical.
What this interaction means in plain words
Imipenem / cilastatin 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
Possible additive neurotoxicity; no established mechanism for the combination.
What to do
Adjust both drugs for renal function and monitor for neurological symptoms. Choose an alternative carbapenem or antiviral in patients with seizure history.
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
- Talimogene laherparepvec + Valacyclovir Major
- Bacitracin + Valacyclovir Moderate
- Cilastatin-imipenem + Valacyclovir Moderate
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Valacyclovir Moderate
- Imipenem / cilastatin / relebactam + Valacyclovir Moderate
- Mycophenolic acid + Valacyclovir Moderate
Frequently asked questions
Can I take Imipenem / cilastatin with Valacyclovir?
MediHelp rates the interaction as moderate. Imipenem / cilastatin 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. Both drugs can lower the seizure threshold, particularly in renal impairment, so combined use may raise seizure risk. The evidence is limited and largely theoretical.
How serious is the interaction between Imipenem / cilastatin 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: Adjust both drugs for renal function and monitor for neurological symptoms. Choose an alternative carbapenem or antiviral in patients with seizure history.
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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