Drug interactions
Doxycycline + Mobocertinib
Severity: Moderate
Doxycycline and Mobocertinib: 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
Mobocertinib is a CYP3A4 substrate that prolongs the QT interval, so any rise in its exposure raises the risk of arrhythmia. Doxycycline is a weak or doubtful CYP3A4 inhibitor, so the real effect is probably small, but the QT consequences justify caution.
What this interaction means in plain words
Doxycycline and Mobocertinib 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
Possible weak inhibition of CYP3A4-mediated mobocertinib metabolism, which is not firmly established for doxycycline.
What to do
Monitor ECG and electrolytes, correct potassium and magnesium, and consider an alternative antibiotic if QTc lengthens.
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 Doxycycline
- Acitretin + Doxycycline Contraindicated
- Aminolevulinic acid + Doxycycline Major
- Cholera vaccine + Doxycycline Major
- Doxycycline + Isotretinoin Major
- Doxycycline + Methoxyflurane Major
- Doxycycline + Microbiota Major
Frequently asked questions
Can I take Doxycycline with Mobocertinib?
MediHelp rates the interaction as moderate. Doxycycline and Mobocertinib 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. Mobocertinib is a CYP3A4 substrate that prolongs the QT interval, so any rise in its exposure raises the risk of arrhythmia. Doxycycline is a weak or doubtful CYP3A4 inhibitor, so the real effect is probably small, but the QT consequences justify caution.
How serious is the interaction between Doxycycline and Mobocertinib?
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 ECG and electrolytes, correct potassium and magnesium, and consider an alternative antibiotic if QTc lengthens.
What other medicines interact with Doxycycline?
MediHelp also lists interactions of Doxycycline with, for example, Acitretin, Aminolevulinic acid, Cholera vaccine. The full list is on the Doxycycline page.
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