Drug interactions
Fosamprenavir + Tamsulosin
Severity: Moderate
Fosamprenavir and Tamsulosin: 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
Fosamprenavir (as amprenavir) is a moderate CYP3A4 inhibitor and can raise tamsulosin concentrations. This increases the risk of hypotension, dizziness and syncope.
What this interaction means in plain words
Fosamprenavir and Tamsulosin 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
Amprenavir inhibits CYP3A4, reducing tamsulosin clearance.
What to do
Monitor for orthostatic hypotension, especially at initiation. Use the lowest effective tamsulosin dose or switch to an alternative if symptomatic.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Fosamprenavir and Tamsulosin, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Tamsulosin
- Alfuzosin + Tamsulosin Major
- Avanafil + Tamsulosin Major
- Ceritinib + Tamsulosin Major
- Clarithromycin + Tamsulosin Major
- Cobicistat + Tamsulosin Major
- Doxazosin + Tamsulosin Major
Frequently asked questions
Can I take Fosamprenavir with Tamsulosin?
MediHelp rates the interaction as moderate. Fosamprenavir and Tamsulosin 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. Fosamprenavir (as amprenavir) is a moderate CYP3A4 inhibitor and can raise tamsulosin concentrations. This increases the risk of hypotension, dizziness and syncope.
How serious is the interaction between Fosamprenavir and Tamsulosin?
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 for orthostatic hypotension, especially at initiation. Use the lowest effective tamsulosin dose or switch to an alternative if symptomatic.
What other medicines interact with Tamsulosin?
MediHelp also lists interactions of Tamsulosin with, for example, Alfuzosin, Avanafil, Ceritinib. The full list is on the Tamsulosin page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
