Drug interactions
Fostemsavir + Lorlatinib
Severity: Major
Fostemsavir 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 is a CYP3A4 inducer that can lower temsavir concentrations, the active form of fostemsavir. Reduced exposure may lead to loss of virologic control and resistance.
What this interaction means in plain words
Fostemsavir 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.
Fostemsavir belongs to Anti Virals; Lorlatinib belongs to Oncology.
Why it happens
Lorlatinib induces CYP3A4, which increases temsavir metabolism and lowers exposure.
What to do
Avoid if possible and consider an alternative regimen. If unavoidable, monitor HIV RNA closely.
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
Other interactions of Fostemsavir
- Apalutamide + Fostemsavir Contraindicated
- Carbamazepine + Fostemsavir Contraindicated
- Enzalutamide + Fostemsavir Contraindicated
- Fostemsavir + Mitotane Contraindicated
- Fostemsavir + Phenytoin Contraindicated
- Fostemsavir + Rifampicin Contraindicated
Frequently asked questions
Can I take Fostemsavir with Lorlatinib?
MediHelp rates the interaction as major. Fostemsavir 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 is a CYP3A4 inducer that can lower temsavir concentrations, the active form of fostemsavir. Reduced exposure may lead to loss of virologic control and resistance.
How serious is the interaction between Fostemsavir 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 if possible and consider an alternative regimen. If unavoidable, monitor HIV RNA closely.
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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