Drug interactions
Guanfacine + Valproic acid
Severity: Moderate
Guanfacine 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
Valproate may raise guanfacine exposure by competing for glucuronidation, and guanfacine exposure has been reported to rise with valproate co-use. Guanfacine may in turn increase valproate levels, and the combination can cause greater sedation and low blood pressure.
What this interaction means in plain words
Guanfacine 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.
Guanfacine belongs to Cardiovascular; Valproic acid belongs to Central Nervous System.
Why it happens
Possible competition for glucuronidation pathways and additive CNS and hemodynamic effects.
What to do
Monitor blood pressure, heart rate and sedation, and consider guanfacine dose reduction if adverse effects occur. Check valproate levels if toxicity is suspected.
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 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
Other interactions of Guanfacine
- Clonidine + Guanfacine Major
- Guanfacine + Lofexidine Major
- Aldesleukin + Guanfacine Moderate
- Amiodarone + Guanfacine Moderate
- Amisulpride + Guanfacine Moderate
- Amitriptyline + Guanfacine Moderate
Frequently asked questions
Can I take Guanfacine with Valproic acid?
MediHelp rates the interaction as moderate. Guanfacine 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. Valproate may raise guanfacine exposure by competing for glucuronidation, and guanfacine exposure has been reported to rise with valproate co-use. Guanfacine may in turn increase valproate levels, and the combination can cause greater sedation and low blood pressure.
How serious is the interaction between Guanfacine 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: Monitor blood pressure, heart rate and sedation, and consider guanfacine dose reduction if adverse effects occur. Check valproate levels if toxicity is suspected.
What other medicines interact with Valproic acid?
MediHelp also lists interactions of Valproic acid with, for example, Ertapenem, Imipenem / cilastatin / relebactam, Imipenem / cilastatin. The full list is on the Valproic acid page.
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