Drug interactions
Dutasteride-tamsulosin + Fosamprenavir
Severity: Major
Dutasteride-tamsulosin and Fosamprenavir: major 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, whose active form amprenavir inhibits CYP3A4, may increase tamsulosin levels, especially when ritonavir-boosted. This raises the risk of hypotension and syncope.
What this interaction means in plain words
Dutasteride-tamsulosin and Fosamprenavir can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
CYP3A4 inhibition by amprenavir (and ritonavir) reduces tamsulosin clearance.
What to do
Avoid the combination if possible. Otherwise monitor blood pressure and counsel on orthostatic symptoms.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Dutasteride-tamsulosin
Frequently asked questions
Can I take Dutasteride-tamsulosin with Fosamprenavir?
MediHelp rates the interaction as major. Dutasteride-tamsulosin and Fosamprenavir can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Fosamprenavir, whose active form amprenavir inhibits CYP3A4, may increase tamsulosin levels, especially when ritonavir-boosted. This raises the risk of hypotension and syncope.
How serious is the interaction between Dutasteride-tamsulosin and Fosamprenavir?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination if possible. Otherwise monitor blood pressure and counsel on orthostatic symptoms.
What other medicines interact with Dutasteride-tamsulosin?
MediHelp also lists interactions of Dutasteride-tamsulosin with, for example, Alfuzosin, Amifostine, Atazanavir. The full list is on the Dutasteride-tamsulosin page.
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