Drug interactions
Isoniazid + Lefamulin
Severity: Moderate
Isoniazid and Lefamulin: 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
Lefamulin is a CYP3A4 substrate and can prolong the QT interval. Isoniazid may modestly increase lefamulin exposure, which could add to QT risk and gastrointestinal effects.
What this interaction means in plain words
Isoniazid and Lefamulin 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.
Isoniazid belongs to Anti Bacterial; Lefamulin belongs to Anti Bacterial.
Why it happens
Weak CYP3A4 inhibition by isoniazid may raise lefamulin concentrations.
What to do
Obtain an ECG if other QT-prolonging drugs or risk factors are present, and correct electrolyte disturbances. Consider an alternative antibacterial if QTc becomes prolonged.
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 Isoniazid
Other interactions of Lefamulin
- Lefamulin + Methadone Contraindicated
- Lefamulin + Pimavanserin Contraindicated
- Lefamulin + Pimozide Contraindicated
- Lefamulin + Quinidine Contraindicated
- Alfuzosin + Lefamulin Major
- Amiodarone + Lefamulin Major
Frequently asked questions
Can I take Isoniazid with Lefamulin?
MediHelp rates the interaction as moderate. Isoniazid and Lefamulin 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. Lefamulin is a CYP3A4 substrate and can prolong the QT interval. Isoniazid may modestly increase lefamulin exposure, which could add to QT risk and gastrointestinal effects.
How serious is the interaction between Isoniazid and Lefamulin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Obtain an ECG if other QT-prolonging drugs or risk factors are present, and correct electrolyte disturbances. Consider an alternative antibacterial if QTc becomes prolonged.
What other medicines interact with Isoniazid?
MediHelp also lists interactions of Isoniazid with, for example, Bacillus calmette-guerin substrain tice, Benzhydrocodone / acetaminophen, Carbamazepine. The full list is on the Isoniazid page.
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