Drug interactions
Primidone + Quetiapine
Severity: Major
Primidone and Quetiapine: major interaction.
Last updated Sources: US FDA label
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
Primidone, partly converted to phenobarbital, induces CYP3A4 and can lower quetiapine concentrations, risking loss of efficacy. Both drugs are sedating, so additive CNS depression can occur.
What this interaction means in plain words
Primidone and Quetiapine 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.
Primidone belongs to Central Nervous System; Quetiapine belongs to Central Nervous System.
Why it happens
CYP3A4 induction increases quetiapine metabolism, plus additive CNS depression.
What to do
Monitor clinical response and sedation, and increase the quetiapine dose if needed. Reduce the dose again if primidone is stopped.
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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References
Other interactions of Quetiapine
- Adagrasib + Quetiapine Major
- Amiodarone + Quetiapine Major
- Amisulpride + Quetiapine Major
- Amoxapine + Quetiapine Major
- Anagrelide + Quetiapine Major
- Apalutamide + Quetiapine Major
Other interactions of Primidone
- Lorlatinib + Primidone Contraindicated
- Lurasidone + Primidone Contraindicated
- Primidone + Ranolazine Contraindicated
- Primidone + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
- Primidone + Voriconazole Contraindicated
- Abiraterone + Primidone Major
Frequently asked questions
Can I take Primidone with Quetiapine?
MediHelp rates the interaction as major. Primidone and Quetiapine 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. Primidone, partly converted to phenobarbital, induces CYP3A4 and can lower quetiapine concentrations, risking loss of efficacy. Both drugs are sedating, so additive CNS depression can occur.
How serious is the interaction between Primidone and Quetiapine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor clinical response and sedation, and increase the quetiapine dose if needed. Reduce the dose again if primidone is stopped.
What other medicines interact with Quetiapine?
MediHelp also lists interactions of Quetiapine with, for example, Adagrasib, Amiodarone, Amisulpride. The full list is on the Quetiapine page.
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