Drug interactions
Isoniazid + Zonisamide
Severity: Minor
Isoniazid and Zonisamide: minor 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 may weakly inhibit CYP3A4, which could modestly raise zonisamide concentrations. Increased drowsiness, dizziness or other CNS effects are possible.
What this interaction means in plain words
Isoniazid and Zonisamide have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Isoniazid belongs to Anti Bacterial; Zonisamide belongs to Central Nervous System.
Why it happens
Possible CYP3A4 inhibition by isoniazid reducing zonisamide clearance.
What to do
Monitor for sedation, ataxia and cognitive effects and reduce zonisamide dose if they occur.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Isoniazid and Zonisamide, 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 Zonisamide
- Zonisamide + Zuranolone Major
- Acetazolamide + Zonisamide Moderate
- Amisulpride + Zonisamide Moderate
- Amobarbital + Zonisamide Moderate
- Apalutamide + Zonisamide Moderate
- Asenapine transdermal + Zonisamide Moderate
Frequently asked questions
Can I take Isoniazid with Zonisamide?
MediHelp rates the interaction as minor. Isoniazid and Zonisamide have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Isoniazid may weakly inhibit CYP3A4, which could modestly raise zonisamide concentrations. Increased drowsiness, dizziness or other CNS effects are possible.
How serious is the interaction between Isoniazid and Zonisamide?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for sedation, ataxia and cognitive effects and reduce zonisamide dose if they occur.
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.
