Drug interactions
Lorlatinib + St john's wort
Severity: Contraindicated
Lorlatinib and St john's wort: contraindicated 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
St John's wort induces CYP3A4 and can reduce lorlatinib exposure, possibly causing loss of disease control. Strong inducers are contraindicated with lorlatinib, and hepatotoxicity has been reported with such combinations.
What this interaction means in plain words
Lorlatinib and St john's wort are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Why it happens
Hyperforin-mediated induction of CYP3A4 (via PXR) increases lorlatinib clearance.
What to do
Advise patients to avoid St John's wort entirely. Stop it for an adequate washout period before starting lorlatinib.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
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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 St john's wort?
MediHelp rates the interaction as contraindicated. Lorlatinib and St john's wort are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. St John's wort induces CYP3A4 and can reduce lorlatinib exposure, possibly causing loss of disease control. Strong inducers are contraindicated with lorlatinib, and hepatotoxicity has been reported with such combinations.
How serious is the interaction between Lorlatinib and St john's wort?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Advise patients to avoid St John's wort entirely. Stop it for an adequate washout period before starting lorlatinib.
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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