Drug interactions
Primidone + Thioridazine
Severity: Moderate
Primidone and Thioridazine: 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
Both drugs cause sedation, so use together can increase drowsiness and impair alertness. Primidone is metabolized to phenobarbital, which induces liver enzymes and may lower thioridazine levels, while thioridazine may lower the seizure threshold.
What this interaction means in plain words
Primidone and Thioridazine 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 belongs to Central Nervous System; Thioridazine belongs to Central Nervous System.
Why it happens
Additive central nervous system depression plus enzyme induction by primidone and its metabolite phenobarbital.
What to do
Monitor sedation and seizure control, and adjust doses by clinical response. Counsel patients about driving and alcohol.
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 Thioridazine
- Abiraterone + Thioridazine Contraindicated
- Adagrasib + Thioridazine Contraindicated
- Amiodarone + Thioridazine Contraindicated
- Amisulpride + Thioridazine Contraindicated
- Amitriptyline + Thioridazine Contraindicated
- Amoxapine + Thioridazine Contraindicated
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 Thioridazine?
MediHelp rates the interaction as moderate. Primidone and Thioridazine 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. Both drugs cause sedation, so use together can increase drowsiness and impair alertness. Primidone is metabolized to phenobarbital, which induces liver enzymes and may lower thioridazine levels, while thioridazine may lower the seizure threshold.
How serious is the interaction between Primidone and Thioridazine?
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 doses by clinical response. Counsel patients about driving and alcohol.
What other medicines interact with Thioridazine?
MediHelp also lists interactions of Thioridazine with, for example, Abiraterone, Adagrasib, Amiodarone. The full list is on the Thioridazine page.
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