Drug interactions
Clonazepam + Primidone
Severity: Moderate
Clonazepam and Primidone: 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
Primidone is metabolised to phenobarbital, so the combination adds sedative and respiratory depressant effects to clonazepam. Enzyme induction may also lower clonazepam concentrations and affect seizure control.
What this interaction means in plain words
Clonazepam and Primidone 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.
Clonazepam belongs to Central Nervous System; Primidone belongs to Central Nervous System.
Why it happens
Additive CNS depression plus induction of CYP3A4 by primidone and its phenobarbital metabolite.
What to do
Monitor sedation and seizure control, and adjust clonazepam dose according to response. Reassess when either drug is started, changed or stopped.
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 Clonazepam
- Calcium / magnesium / potassium / sodium oxybates + Clonazepam Contraindicated
- Clonazepam + Sodium oxybate Contraindicated
- Alfentanil + Clonazepam Major
- Alprazolam + Clonazepam Major
- Amobarbital + Clonazepam Major
- Belladonna and opium + Clonazepam 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 Clonazepam with Primidone?
MediHelp rates the interaction as moderate. Clonazepam and Primidone 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. Primidone is metabolised to phenobarbital, so the combination adds sedative and respiratory depressant effects to clonazepam. Enzyme induction may also lower clonazepam concentrations and affect seizure control.
How serious is the interaction between Clonazepam and Primidone?
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 sedation and seizure control, and adjust clonazepam dose according to response. Reassess when either drug is started, changed or stopped.
What other medicines interact with Clonazepam?
MediHelp also lists interactions of Clonazepam with, for example, Calcium / magnesium / potassium / sodium oxybates, Sodium oxybate, Alfentanil. The full list is on the Clonazepam page.
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