Drug interactions
Lapatinib + Pentamidine
Severity: Major
Lapatinib and Pentamidine: major 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
Both drugs can prolong the QT interval, so combined use raises the risk of torsades de pointes. Risk is greater with intravenous pentamidine, electrolyte disturbance or underlying heart disease.
What this interaction means in plain words
Lapatinib and Pentamidine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Lapatinib belongs to Oncology; Pentamidine belongs to Anti Parasitic.
Why it happens
Additive pharmacodynamic QTc prolongation.
What to do
Avoid if possible. If necessary, obtain a baseline ECG, correct potassium and magnesium, and monitor the QTc.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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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
Other interactions of Pentamidine
- Clomipramine + Pentamidine Contraindicated
- Desipramine + Pentamidine Contraindicated
- Dronedarone + Pentamidine Contraindicated
- Moxifloxacin + Pentamidine Contraindicated
- Nortriptyline + Pentamidine Contraindicated
- Pentamidine + Pimozide Contraindicated
Frequently asked questions
Can I take Lapatinib with Pentamidine?
MediHelp rates the interaction as major. Lapatinib and Pentamidine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Both drugs can prolong the QT interval, so combined use raises the risk of torsades de pointes. Risk is greater with intravenous pentamidine, electrolyte disturbance or underlying heart disease.
How serious is the interaction between Lapatinib and Pentamidine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid if possible. If necessary, obtain a baseline ECG, correct potassium and magnesium, and monitor the QTc.
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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