Atenolol and Cobicistat: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 15, 2026 · Source data updated Jul 11, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Cobicistat
Atenolol
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
Here's what's going on. Cobicistat (Tybost) is a medicine that can slow down how your body clears out certain other drugs. When it's taken with a heart-rhythm or blood-pressure medicine like atenolol, the level of that medicine in your body may go up a bit. That could mean stronger effects, such as your heart rate or blood pressure dropping more than expected.
The good news: this is mostly a theoretical concern, and it's very manageable. Keep taking both exactly as prescribed, and let your care team know if you feel dizzy, unusually tired, or notice a slow heartbeat. They can watch you closely and adjust your dose if needed.
Effect: Cobicistat may increase exposure to co-administered antiarrhythmics/cardiac agents, including atenolol, via reduced clearance.
- Direction: increased exposure (Cmax/AUC) of the affected agent, potentially enhancing bradycardic and hypotensive effects.
- Mechanism: unknown/unspecified; cobicistat is a potent CYP3A and P-gp inhibitor. Note atenolol is minimally metabolized and largely renally eliminated, so any real-world effect may be limited.
- Evidence: theoretical.
- Onset: unspecified.
- Management: clinical monitoring on coadministration (heart rate, blood pressure). Individualize dose if excessive beta-blockade emerges.
What happens
Increased antiarrhythmic exposure
Interaction Deep Dive
Giving cobicistat together with antiarrhythmics may raise antiarrhythmic exposure. When these agents are used concurrently, clinical monitoring is advised1234.
Why it happens (mechanism)
Unknown
How to manage this interaction
What your care team may do:
- Monitor you more closely, especially your heart rate and blood pressure, when these two are used together.
- Adjust and individualize your atenolol dose if signs of too much beta-blockade appear.
What you can do:
- Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise.
- Tell your pharmacist or doctor if you feel dizzy, faint, very tired, or notice an unusually slow heartbeat.
- Bring up this combination at your next visit so your team is aware and can watch for it.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Atenolol and Cobicistat together?
Cobicistat may raise atenolol levels and increase its heart-slowing, blood-pressure-lowering effects, but this is a theoretical concern. Keep taking both as prescribed and let your care team monitor you and adjust the dose if needed. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Atenolol and Cobicistat interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Atenolol and Cobicistat interaction managed?
What your care team may do: Monitor you more closely, especially your heart rate and blood pressure, when these two are used together. Adjust and individualize your atenolol dose if signs of too much beta-blockade appear. What you can do: Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise. Tell your pharmacist or doctor if you feel dizzy, faint, very tired,… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Atenolol or Cobicistat need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there anything you'd monitor while I'm on both?
References (4)
- Product Information: SYMTUZA(R) oral tablets, darunavir, cobicistat, emtricitabine, tenofovir alafenamide oral tablets. Janssen Products, LP (per FDA), Horsham, PA, 2023. DailyMed
- Product Information: TYBOST(R) oral tablets, cobicistat oral tablets. Gilead Sciences Inc (per FDA), Foster City, CA, 2025. DailyMed
- Product Information: PREZCOBIX® PED oral tablets for suspension, darunavir cobicistat oral tablets for suspension. Janssen Products, LP (per FDA), Horsham, PA, 2026. DailyMed
- Product Information: PREZCOBIX® oral tablets, darunavir cobicistat oral tablets. Janssen Products, LP (per FDA), Horsham, PA, 2026. DailyMed
Keep reading about Cobicistat
Keep reading about Atenolol
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