Drug interactions
Isoniazid + Lorlatinib
Severity: Moderate
Isoniazid and Lorlatinib: 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
Lorlatinib is metabolized mainly by CYP3A4, so inhibition by isoniazid may raise its levels. This could increase hyperlipidemia, CNS effects and PR interval prolongation. Isoniazid is also hepatotoxic and lorlatinib can raise transaminases.
What this interaction means in plain words
Isoniazid and Lorlatinib 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; Lorlatinib belongs to Oncology.
Why it happens
Isoniazid inhibits CYP3A4, reducing lorlatinib metabolism, with additive hepatotoxic potential.
What to do
Monitor liver enzymes, lipids, ECG and CNS effects. Reduce the lorlatinib dose if toxicity develops.
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 Lorlatinib
- Amobarbital + Lorlatinib Contraindicated
- Apalutamide + Lorlatinib Contraindicated
- Butabarbital + Lorlatinib Contraindicated
- Carbamazepine + Lorlatinib Contraindicated
- Enzalutamide + Lorlatinib Contraindicated
- Fosphenytoin + Lorlatinib Contraindicated
Frequently asked questions
Can I take Isoniazid with Lorlatinib?
MediHelp rates the interaction as moderate. Isoniazid and Lorlatinib 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. Lorlatinib is metabolized mainly by CYP3A4, so inhibition by isoniazid may raise its levels. This could increase hyperlipidemia, CNS effects and PR interval prolongation. Isoniazid is also hepatotoxic and lorlatinib can raise transaminases.
How serious is the interaction between Isoniazid and Lorlatinib?
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 liver enzymes, lipids, ECG and CNS effects. Reduce the lorlatinib dose if toxicity develops.
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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