Drug interactions
Isoniazid + Selegiline
Severity: Moderate
Isoniazid and Selegiline: 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 inhibiting activity, and selegiline is an MAO-B inhibitor that loses selectivity at higher doses. Together they may add to serotonergic or hypertensive effects, although clinically significant reactions are uncommon and mostly described in case reports.
What this interaction means in plain words
Isoniazid and Selegiline 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; Selegiline belongs to Central Nervous System.
Why it happens
Additive weak MAO inhibition by isoniazid with selegiline, which may increase monoamine and serotonin levels.
What to do
Monitor for agitation, tremor, hyperthermia, sweating and blood pressure changes when starting or increasing either drug. Stop one agent if features of serotonin toxicity appear.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Isoniazid and Selegiline, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Isoniazid
Other interactions of Selegiline
- Amitriptyline + Selegiline Contraindicated
- Amoxapine + Selegiline Contraindicated
- Atomoxetine + Selegiline Contraindicated
- Benzphetamine + Selegiline Contraindicated
- Brimonidine + Selegiline Contraindicated
- Buprenorphine long-acting + Selegiline Contraindicated
Frequently asked questions
Can I take Isoniazid with Selegiline?
MediHelp rates the interaction as moderate. Isoniazid and Selegiline 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 inhibiting activity, and selegiline is an MAO-B inhibitor that loses selectivity at higher doses. Together they may add to serotonergic or hypertensive effects, although clinically significant reactions are uncommon and mostly described in case reports.
How serious is the interaction between Isoniazid and Selegiline?
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, sweating and blood pressure changes when starting or increasing either drug. Stop one agent if features of serotonin toxicity appear.
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.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
