Drug interactions
Lorlatinib + Toremifene
Severity: Moderate
Lorlatinib and Toremifene: moderate 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 may lower toremifene concentrations, which could reduce antiestrogen efficacy. Toremifene prolongs QT, but the effect of lowered exposure is reduced risk rather than added risk.
What this interaction means in plain words
Lorlatinib and Toremifene can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Lorlatinib belongs to Oncology; Toremifene belongs to Endocrine.
Why it happens
Lorlatinib induces CYP3A4, increasing the metabolism of toremifene, a CYP3A4 substrate.
What to do
Monitor treatment response. Toremifene dose increase may be needed with CYP3A4 inducers, with ECG monitoring.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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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 Toremifene
- Amiodarone + Toremifene Contraindicated
- Dronedarone + Toremifene Contraindicated
- Nilotinib + Toremifene Contraindicated
- Pimozide + Toremifene Contraindicated
- Quinidine + Toremifene Contraindicated
- Ribociclib + Toremifene Contraindicated
Frequently asked questions
Can I take Lorlatinib with Toremifene?
MediHelp rates the interaction as moderate. Lorlatinib and Toremifene can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Lorlatinib may lower toremifene concentrations, which could reduce antiestrogen efficacy. Toremifene prolongs QT, but the effect of lowered exposure is reduced risk rather than added risk.
How serious is the interaction between Lorlatinib and Toremifene?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor treatment response. Toremifene dose increase may be needed with CYP3A4 inducers, with ECG monitoring.
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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