Drug interactions
Ritonavir + Zonisamide
Severity: Minor
Ritonavir 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
Ritonavir is a strong CYP3A4 inhibitor and may increase zonisamide exposure. Higher levels can increase somnolence, dizziness and other adverse effects.
What this interaction means in plain words
Ritonavir 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.
Ritonavir belongs to Anti Virals; Zonisamide belongs to Central Nervous System.
Why it happens
Ritonavir inhibits CYP3A4, reducing the metabolism of zonisamide.
What to do
Monitor for sedation and other zonisamide adverse effects after starting ritonavir. Lower the zonisamide dose if toxicity occurs.
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?
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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 Ritonavir
- Alfuzosin + Ritonavir Contraindicated
- Amiodarone + Ritonavir Contraindicated
- Avanafil + Ritonavir Contraindicated
- Colchicine + Ritonavir Contraindicated
- Dronedarone + Ritonavir Contraindicated
- Eletriptan + Ritonavir Contraindicated
Frequently asked questions
Can I take Ritonavir with Zonisamide?
MediHelp rates the interaction as minor. Ritonavir 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. Ritonavir is a strong CYP3A4 inhibitor and may increase zonisamide exposure. Higher levels can increase somnolence, dizziness and other adverse effects.
How serious is the interaction between Ritonavir 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 and other zonisamide adverse effects after starting ritonavir. Lower the zonisamide dose if toxicity occurs.
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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