Drug interactions
Fentanyl transmucosal + Lapatinib
Severity: Moderate
Fentanyl transmucosal and Lapatinib: 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 may increase fentanyl exposure by inhibiting CYP3A4, with a higher risk of sedation and respiratory depression. Transmucosal fentanyl is used in opioid-tolerant patients, and overdose can be dangerous.
What this interaction means in plain words
Fentanyl transmucosal and Lapatinib 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.
Why it happens
CYP3A4 inhibition by lapatinib reduces fentanyl metabolism.
What to do
Monitor for respiratory depression and sedation, and consider reducing the fentanyl dose or titrating more slowly. Reassess if lapatinib is started or stopped.
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 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 Fentanyl transmucosal with Lapatinib?
MediHelp rates the interaction as moderate. Fentanyl transmucosal and Lapatinib 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 may increase fentanyl exposure by inhibiting CYP3A4, with a higher risk of sedation and respiratory depression. Transmucosal fentanyl is used in opioid-tolerant patients, and overdose can be dangerous.
How serious is the interaction between Fentanyl transmucosal and Lapatinib?
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 respiratory depression and sedation, and consider reducing the fentanyl dose or titrating more slowly. Reassess if lapatinib is started or stopped.
What other medicines interact with Lapatinib?
MediHelp also lists interactions of Lapatinib with, for example, Dofetilide, Ibutilide, Pimozide. The full list is on the Lapatinib page.
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