Drug interactions
Cilastatin-imipenem + Valproic acid
Severity: Major
Cilastatin-imipenem and Valproic acid: 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, rapidly and markedly lower serum valproate concentrations, which can lead to loss of seizure control. The effect begins within a day or two and may persist for some days after stopping the carbapenem.
What this interaction means in plain words
Cilastatin-imipenem and Valproic acid 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.
Cilastatin-imipenem belongs to Anti Bacterial; Valproic acid belongs to Central Nervous System.
Why it happens
Carbapenems inhibit hydrolysis of valproate glucuronide and may reduce its absorption and distribution, lowering valproate levels.
What to do
Avoid the combination and use a non-carbapenem antibiotic. Increasing the valproate dose is usually ineffective, so add or switch to another anticonvulsant if a carbapenem is unavoidable.
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
Other interactions of Valproic acid
- Ertapenem + Valproic acid Contraindicated
- Imipenem / cilastatin / relebactam + Valproic acid Contraindicated
- Imipenem / cilastatin + Valproic acid Contraindicated
- Meropenem / vaborbactam + Valproic acid Contraindicated
- Meropenem + Valproic acid Contraindicated
- Calcium / magnesium / potassium / sodium oxybates + Valproic acid Major
Frequently asked questions
Can I take Cilastatin-imipenem with Valproic acid?
MediHelp rates the interaction as major. Cilastatin-imipenem and Valproic acid 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, rapidly and markedly lower serum valproate concentrations, which can lead to loss of seizure control. The effect begins within a day or two and may persist for some days after stopping the carbapenem.
How serious is the interaction between Cilastatin-imipenem and Valproic acid?
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. Increasing the valproate dose is usually ineffective, so add or switch to another anticonvulsant if a carbapenem is unavoidable.
What other medicines interact with Cilastatin-imipenem?
MediHelp also lists interactions of Cilastatin-imipenem with, for example, Divalproex, Ganciclovir, Bcg intravesical live. The full list is on the Cilastatin-imipenem page.
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