Drug interactions
Topiramate + Zonisamide
Severity: Moderate
Topiramate and Zonisamide: 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
Both drugs inhibit carbonic anhydrase, so combined use raises the risk of metabolic acidosis and kidney stones. A pharmacokinetic interaction through CYP3A4 is unlikely to be important.
What this interaction means in plain words
Topiramate and Zonisamide 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.
Topiramate belongs to Central Nervous System; Zonisamide belongs to Central Nervous System.
Why it happens
Additive carbonic anhydrase inhibition; topiramate may also weakly induce CYP3A4 at higher doses.
What to do
Monitor serum bicarbonate periodically and encourage adequate fluid intake. Reduce the dose or stop one drug if acidosis persists.
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 Zonisamide
- Zonisamide + Zuranolone Major
- Acetazolamide + Zonisamide Moderate
- Amisulpride + Zonisamide Moderate
- Amobarbital + Zonisamide Moderate
- Apalutamide + Zonisamide Moderate
- Asenapine transdermal + Zonisamide Moderate
Other interactions of Topiramate
Frequently asked questions
Can I take Topiramate with Zonisamide?
MediHelp rates the interaction as moderate. Topiramate and Zonisamide 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. Both drugs inhibit carbonic anhydrase, so combined use raises the risk of metabolic acidosis and kidney stones. A pharmacokinetic interaction through CYP3A4 is unlikely to be important.
How serious is the interaction between Topiramate and Zonisamide?
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 serum bicarbonate periodically and encourage adequate fluid intake. Reduce the dose or stop one drug if acidosis persists.
What other medicines interact with Zonisamide?
MediHelp also lists interactions of Zonisamide with, for example, Zuranolone, Acetazolamide, Amisulpride. The full list is on the Zonisamide page.
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