Drug interactions
Lorlatinib + Saquinavir
Severity: Major
Lorlatinib and Saquinavir: major interaction.
Last updated Sources: Health Canada product monograph
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
Saquinavir, a strong CYP3A inhibitor, can increase lorlatinib exposure and toxicity. Lorlatinib may in turn reduce saquinavir levels, and saquinavir itself can prolong QT and PR intervals.
What this interaction means in plain words
Lorlatinib and Saquinavir 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
Saquinavir inhibits CYP3A4, reducing lorlatinib clearance; lorlatinib induces CYP3A4, lowering saquinavir exposure.
What to do
Avoid combination; if unavoidable, reduce lorlatinib dose per labeling and monitor ECG, lipids, liver enzymes and HIV viral load.
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 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 Lorlatinib with Saquinavir?
MediHelp rates the interaction as major. Lorlatinib and Saquinavir 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. Saquinavir, a strong CYP3A inhibitor, can increase lorlatinib exposure and toxicity. Lorlatinib may in turn reduce saquinavir levels, and saquinavir itself can prolong QT and PR intervals.
How serious is the interaction between Lorlatinib and Saquinavir?
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 combination; if unavoidable, reduce lorlatinib dose per labeling and monitor ECG, lipids, liver enzymes and HIV viral load.
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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