Drug interactions
Cobicistat + Sildenafil
Severity: Contraindicated
Cobicistat and Sildenafil: contraindicated 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 is a strong CYP3A inhibitor that substantially increases sildenafil concentrations. This raises the risk of marked hypotension, syncope, visual effects and prolonged erection.
What this interaction means in plain words
Cobicistat and Sildenafil are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Cobicistat belongs to Miscellaneous; Sildenafil belongs to Genitourinary.
Why it happens
Cobicistat inhibits CYP3A4, reducing sildenafil clearance and first-pass metabolism.
What to do
Avoid the combination when sildenafil is used chronically for pulmonary arterial hypertension. For erectile dysfunction, limit sildenafil to 25 mg no more than once every 48 hours and monitor blood pressure.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
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Other interactions of Sildenafil
- Amyl nitrite + Sildenafil Contraindicated
- Atazanavir + Sildenafil Contraindicated
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Sildenafil Contraindicated
- Glyceryl trinitrate pr + Sildenafil Contraindicated
- Isosorbide dinitrate + Sildenafil Contraindicated
- Isosorbide mononitrate + Sildenafil Contraindicated
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 Sildenafil?
MediHelp rates the interaction as contraindicated. Cobicistat and Sildenafil are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. Cobicistat is a strong CYP3A inhibitor that substantially increases sildenafil concentrations. This raises the risk of marked hypotension, syncope, visual effects and prolonged erection.
How serious is the interaction between Cobicistat and Sildenafil?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination when sildenafil is used chronically for pulmonary arterial hypertension. For erectile dysfunction, limit sildenafil to 25 mg no more than once every 48 hours and monitor blood pressure.
What other medicines interact with Sildenafil?
MediHelp also lists interactions of Sildenafil with, for example, Amyl nitrite, Atazanavir, Elvitegravir / cobicistat / emtricitabine / tenofovir df. The full list is on the Sildenafil page.
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