Drug interactions
Fosamprenavir + Lorlatinib
Severity: Major
Fosamprenavir and Lorlatinib: 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
Lorlatinib induces CYP3A and may lower amprenavir exposure, risking virologic failure. Boosted fosamprenavir may also inhibit CYP3A and raise lorlatinib levels.
What this interaction means in plain words
Fosamprenavir and Lorlatinib 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
Lorlatinib induces CYP3A4 increasing amprenavir clearance; the protease inhibitor inhibits CYP3A4 and raises lorlatinib.
What to do
Avoid the combination and choose another antiretroviral. If unavoidable, monitor HIV viral load and lorlatinib toxicity such as lipids and liver tests.
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 Lorlatinib
- Amobarbital + Lorlatinib Contraindicated
- Apalutamide + Lorlatinib Contraindicated
- Butabarbital + Lorlatinib Contraindicated
- Carbamazepine + Lorlatinib Contraindicated
- Enzalutamide + Lorlatinib Contraindicated
- Fosphenytoin + Lorlatinib Contraindicated
Frequently asked questions
Can I take Fosamprenavir with Lorlatinib?
MediHelp rates the interaction as major. Fosamprenavir and Lorlatinib 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. Lorlatinib induces CYP3A and may lower amprenavir exposure, risking virologic failure. Boosted fosamprenavir may also inhibit CYP3A and raise lorlatinib levels.
How serious is the interaction between Fosamprenavir and Lorlatinib?
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 and choose another antiretroviral. If unavoidable, monitor HIV viral load and lorlatinib toxicity such as lipids and liver tests.
What other medicines interact with Lorlatinib?
MediHelp also lists interactions of Lorlatinib with, for example, Amobarbital, Apalutamide, Butabarbital. The full list is on the Lorlatinib page.
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