Drug interactions
Cilastatin-imipenem + Divalproex
Severity: Major
Cilastatin-imipenem and Divalproex: 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
Carbapenems, including imipenem, cause a rapid and marked fall in serum valproate concentrations. This can lead to loss of seizure control, and the effect may persist for days after stopping the carbapenem. Increasing the valproate dose does not reliably overcome it.
What this interaction means in plain words
Cilastatin-imipenem and Divalproex 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
Carbapenems inhibit acylpeptide hydrolase, reducing hydrolysis of valproate glucuronide back to valproate, and may also decrease valproate absorption and distribution into tissues.
What to do
Avoid the combination and use a non-carbapenem antibiotic. If a carbapenem is essential, add alternative anticonvulsant coverage and monitor valproate levels and seizure activity.
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 Cilastatin-imipenem
Frequently asked questions
Can I take Cilastatin-imipenem with Divalproex?
MediHelp rates the interaction as major. Cilastatin-imipenem and Divalproex 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. Carbapenems, including imipenem, cause a rapid and marked fall in serum valproate concentrations. This can lead to loss of seizure control, and the effect may persist for days after stopping the carbapenem. Increasing the valproate dose does not reliably overcome it.
How serious is the interaction between Cilastatin-imipenem and Divalproex?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination and use a non-carbapenem antibiotic. If a carbapenem is essential, add alternative anticonvulsant coverage and monitor valproate levels and seizure activity.
What other medicines interact with Cilastatin-imipenem?
MediHelp also lists interactions of Cilastatin-imipenem with, for example, Ganciclovir, Valproic acid, Bcg intravesical live. The full list is on the Cilastatin-imipenem page.
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