Drug interactions
Primidone + Timolol
Severity: Moderate
Primidone and Timolol: 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 metabolized to phenobarbital, which induces hepatic enzymes and may lower timolol concentrations. Beta-blocker effect on heart rate and blood pressure may be reduced.
What this interaction means in plain words
Primidone and Timolol 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; Timolol belongs to Cardiovascular.
Why it happens
Enzyme induction by primidone and its phenobarbital metabolite increases hepatic clearance of timolol.
What to do
Monitor heart rate and blood pressure and increase the timolol dose if needed; reassess when primidone is 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 Timolol
- Acebutolol + Timolol Major
- Albuterol + Timolol Major
- Aldesleukin + Timolol Major
- Amifostine + Timolol Major
- Amiodarone + Timolol Major
- Arformoterol + Timolol 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 Timolol?
MediHelp rates the interaction as moderate. Primidone and Timolol 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 metabolized to phenobarbital, which induces hepatic enzymes and may lower timolol concentrations. Beta-blocker effect on heart rate and blood pressure may be reduced.
How serious is the interaction between Primidone and Timolol?
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 heart rate and blood pressure and increase the timolol dose if needed; reassess when primidone is changed or stopped.
What other medicines interact with Timolol?
MediHelp also lists interactions of Timolol with, for example, Acebutolol, Albuterol, Aldesleukin. The full list is on the Timolol page.
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