Drug interactions
Ethinylestradiol + Lorlatinib
Severity: Major
Ethinylestradiol and Lorlatinib: 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
Lorlatinib may reduce ethinylestradiol exposure, and its labeling notes that hormonal contraceptives may be less effective. This creates a risk of contraceptive failure, which matters because lorlatinib is potentially teratogenic.
What this interaction means in plain words
Ethinylestradiol 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 the metabolism of ethinylestradiol.
What to do
Advise an effective non-hormonal contraceptive method during lorlatinib therapy rather than relying on hormonal contraception alone.
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 Ethinylestradiol with Lorlatinib?
MediHelp rates the interaction as major. Ethinylestradiol 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 may reduce ethinylestradiol exposure, and its labeling notes that hormonal contraceptives may be less effective. This creates a risk of contraceptive failure, which matters because lorlatinib is potentially teratogenic.
How serious is the interaction between Ethinylestradiol 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: Advise an effective non-hormonal contraceptive method during lorlatinib therapy rather than relying on hormonal contraception alone.
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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