Drug interactions
Penbutolol + Timolol
Severity: Moderate
Penbutolol 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
Both are non-selective beta-blockers, so use together duplicates therapy and increases the risk of bradycardia, hypotension and AV block. It brings little extra benefit.
What this interaction means in plain words
Penbutolol 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.
Why it happens
Additive beta-adrenergic receptor blockade.
What to do
Avoid duplicate beta-blocker therapy and use one agent. If both are used, monitor heart rate, blood pressure and ECG.
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
Frequently asked questions
Can I take Penbutolol with Timolol?
MediHelp rates the interaction as moderate. Penbutolol 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. Both are non-selective beta-blockers, so use together duplicates therapy and increases the risk of bradycardia, hypotension and AV block. It brings little extra benefit.
How serious is the interaction between Penbutolol 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: Avoid duplicate beta-blocker therapy and use one agent. If both are used, monitor heart rate, blood pressure and ECG.
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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