Drug interactions
Fentanyl + Valproic acid
Severity: Moderate
Fentanyl and Valproic acid: 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
Valproic acid can cause drowsiness and, with fentanyl, may increase sedation and CNS depression. Alertness and psychomotor performance may be impaired.
What this interaction means in plain words
Fentanyl and Valproic acid 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.
Fentanyl belongs to Musculoskeletal; Valproic acid belongs to Central Nervous System.
Why it happens
Additive CNS depressant effects.
What to do
Use the lowest effective fentanyl dose and monitor for sedation and respiratory depression, especially at initiation or dose changes.
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 Fentanyl
- Alvimopan + Fentanyl Contraindicated
- Fentanyl + Isocarboxazid Contraindicated
- Fentanyl + Olanzapine / samidorphan Contraindicated
- Fentanyl + Phenelzine Contraindicated
- Fentanyl + Tranylcypromine Contraindicated
- Alfentanil + Fentanyl Major
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 Fentanyl with Valproic acid?
MediHelp rates the interaction as moderate. Fentanyl and Valproic acid 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. Valproic acid can cause drowsiness and, with fentanyl, may increase sedation and CNS depression. Alertness and psychomotor performance may be impaired.
How serious is the interaction between Fentanyl and Valproic acid?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use the lowest effective fentanyl dose and monitor for sedation and respiratory depression, especially at initiation or dose changes.
What other medicines interact with Fentanyl?
MediHelp also lists interactions of Fentanyl with, for example, Alvimopan, Isocarboxazid, Olanzapine / samidorphan. The full list is on the Fentanyl page.
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