Drug interactions
Butalbital + Lapatinib
Severity: Moderate
Butalbital 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
Butalbital is a barbiturate and is expected to induce CYP3A4, which may lower lapatinib plasma concentrations. Reduced exposure could compromise the antitumor efficacy of lapatinib.
What this interaction means in plain words
Butalbital 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
Barbiturate-mediated induction of CYP3A4 increases the metabolic clearance of lapatinib.
What to do
Avoid regular use of butalbital with lapatinib where an alternative analgesic is possible. If the combination is unavoidable, consider a lapatinib dose increase per labeling for strong inducers and monitor for loss of response.
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 Butalbital with Lapatinib?
MediHelp rates the interaction as moderate. Butalbital 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. Butalbital is a barbiturate and is expected to induce CYP3A4, which may lower lapatinib plasma concentrations. Reduced exposure could compromise the antitumor efficacy of lapatinib.
How serious is the interaction between Butalbital 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: Avoid regular use of butalbital with lapatinib where an alternative analgesic is possible. If the combination is unavoidable, consider a lapatinib dose increase per labeling for strong inducers and monitor for loss of response.
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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