Drug interactions
Cobicistat + Timolol
Severity: Moderate
Cobicistat 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
Cobicistat inhibits CYP2D6, the main enzyme metabolizing timolol, so timolol exposure may increase. This can cause bradycardia, hypotension and AV block, and systemic effects can occur even with eye drops.
What this interaction means in plain words
Cobicistat 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.
Cobicistat belongs to Miscellaneous; Timolol belongs to Cardiovascular.
Why it happens
Inhibition of CYP2D6-mediated timolol metabolism reduces its clearance.
What to do
Monitor heart rate and blood pressure, and consider a lower timolol dose or an alternative beta-blocker if bradycardia or conduction abnormalities occur.
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
- Aldesleukin + Timolol Major
- Amifostine + Timolol Major
- Amiodarone + Timolol Major
- Arformoterol + Timolol Major
- Atenolol-chlorthalidone + Timolol Major
Other interactions of Cobicistat
- Alfuzosin + Cobicistat Contraindicated
- Apalutamide + Cobicistat Contraindicated
- Cobicistat + Colchicine Contraindicated
- Cobicistat + Dronedarone Contraindicated
- Cobicistat + Eletriptan Contraindicated
- Cobicistat + Eplerenone Contraindicated
Frequently asked questions
Can I take Cobicistat with Timolol?
MediHelp rates the interaction as moderate. Cobicistat 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. Cobicistat inhibits CYP2D6, the main enzyme metabolizing timolol, so timolol exposure may increase. This can cause bradycardia, hypotension and AV block, and systemic effects can occur even with eye drops.
How serious is the interaction between Cobicistat 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 consider a lower timolol dose or an alternative beta-blocker if bradycardia or conduction abnormalities occur.
What other medicines interact with Timolol?
MediHelp also lists interactions of Timolol with, for example, Acebutolol, Aldesleukin, Amifostine. The full list is on the Timolol page.
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