Drug interactions
Lapatinib + Tofacitinib
Severity: Moderate
Lapatinib and Tofacitinib: 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
Lapatinib inhibits CYP3A4 and may increase tofacitinib exposure. This could heighten the risk of infection and cytopenias.
What this interaction means in plain words
Lapatinib and Tofacitinib 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.
Lapatinib belongs to Oncology; Tofacitinib belongs to Musculoskeletal.
Why it happens
Inhibition of CYP3A4-mediated tofacitinib metabolism by lapatinib.
What to do
Monitor for infection and blood count changes; reduce the tofacitinib dose if a potent CYP2C19 inhibitor is also used.
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 Tofacitinib
- Baricitinib + Tofacitinib Contraindicated
- Cladribine + Tofacitinib Contraindicated
- Tofacitinib + Upadacitinib Contraindicated
- Abatacept + Tofacitinib Major
- Anti-thymocyte + Tofacitinib Major
- Antithymocyte globulin equine + Tofacitinib Major
Other interactions of Lapatinib
- Dofetilide + Lapatinib Contraindicated
- Ibutilide + Lapatinib Contraindicated
- Lapatinib + Pimozide Contraindicated
- Lapatinib + Saquinavir Contraindicated
- Lapatinib + Thioridazine Contraindicated
- Adagrasib + Lapatinib Major
Frequently asked questions
Can I take Lapatinib with Tofacitinib?
MediHelp rates the interaction as moderate. Lapatinib and Tofacitinib 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. Lapatinib inhibits CYP3A4 and may increase tofacitinib exposure. This could heighten the risk of infection and cytopenias.
How serious is the interaction between Lapatinib and Tofacitinib?
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 for infection and blood count changes; reduce the tofacitinib dose if a potent CYP2C19 inhibitor is also used.
What other medicines interact with Tofacitinib?
MediHelp also lists interactions of Tofacitinib with, for example, Baricitinib, Cladribine, Upadacitinib. The full list is on the Tofacitinib page.
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