Drug interactions
Amoxapine + Isoniazid
Severity: Moderate
Amoxapine and Isoniazid: 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
Isoniazid has weak monoamine oxidase inhibitory activity, and amoxapine inhibits serotonin and norepinephrine reuptake. Serotonergic excess is possible but uncommon, and amoxapine also lowers seizure threshold.
What this interaction means in plain words
Amoxapine and Isoniazid 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
Weak MAO inhibition by isoniazid combined with reuptake inhibition by amoxapine, plus additive seizure threshold lowering.
What to do
Monitor for agitation, tremor, hyperthermia and seizures, especially when starting or increasing doses. Reduce or stop amoxapine if serotonin toxicity is suspected.
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
Frequently asked questions
Can I take Amoxapine with Isoniazid?
MediHelp rates the interaction as moderate. Amoxapine and Isoniazid 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 has weak monoamine oxidase inhibitory activity, and amoxapine inhibits serotonin and norepinephrine reuptake. Serotonergic excess is possible but uncommon, and amoxapine also lowers seizure threshold.
How serious is the interaction between Amoxapine and Isoniazid?
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 for agitation, tremor, hyperthermia and seizures, especially when starting or increasing doses. Reduce or stop amoxapine if serotonin toxicity is suspected.
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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