Drug interactions
Carbamazepine + Fosamprenavir
Severity: Major
Carbamazepine and Fosamprenavir: major interaction.
Last updated Sources: US FDA label
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
Carbamazepine can lower amprenavir concentrations, risking virologic failure and resistance. Amprenavir may also raise carbamazepine levels, especially with ritonavir boosting.
What this interaction means in plain words
Carbamazepine 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
Carbamazepine induces CYP3A4 and P-gp, increasing amprenavir clearance.
What to do
Avoid if possible and choose an alternative anticonvulsant or antiretroviral. If used, monitor HIV viral load and carbamazepine levels.
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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References
Other interactions of Carbamazepine
- Artemether / lumefantrine + Carbamazepine Contraindicated
- Cabotegravir + Carbamazepine Contraindicated
- Carbamazepine + Delamanid Contraindicated
- Carbamazepine + Dienogest / estradiol valerate Contraindicated
- Carbamazepine + Doravirine Contraindicated
- Carbamazepine + Elbasvir / grazoprevir Contraindicated
Frequently asked questions
Can I take Carbamazepine with Fosamprenavir?
MediHelp rates the interaction as major. Carbamazepine 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. Carbamazepine can lower amprenavir concentrations, risking virologic failure and resistance. Amprenavir may also raise carbamazepine levels, especially with ritonavir boosting.
How serious is the interaction between Carbamazepine 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 if possible and choose an alternative anticonvulsant or antiretroviral. If used, monitor HIV viral load and carbamazepine levels.
What other medicines interact with Carbamazepine?
MediHelp also lists interactions of Carbamazepine with, for example, Artemether / lumefantrine, Cabotegravir, Delamanid. The full list is on the Carbamazepine page.
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