Drug interactions
Ivermectin + Phenytoin
Severity: Minor
Ivermectin and Phenytoin: 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
Phenytoin is an enzyme inducer, and it may modestly lower ivermectin exposure through CYP3A4 induction. This is theoretical and not well documented, so antiparasitic efficacy is unlikely to be meaningfully affected.
What this interaction means in plain words
Ivermectin and Phenytoin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Ivermectin belongs to Anti Parasitic; Phenytoin belongs to Central Nervous System.
Why it happens
Phenytoin may induce CYP3A4 and efflux transporters, increasing ivermectin clearance; the effect is predicted rather than demonstrated.
What to do
No dose change is needed; assess treatment response and repeat ivermectin if parasitological cure is not achieved.
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 Ivermectin
- Erdafitinib + Ivermectin Moderate
- Ivermectin + Lasmiditan Moderate
- Ivermectin + Quinidine Moderate
- Ivermectin + Rifampin Moderate
- Ivermectin + Sotorasib Moderate
- Ivermectin + Tepotinib Moderate
Other interactions of Phenytoin
- Artemether / lumefantrine + Phenytoin Contraindicated
- Bictegravir + Phenytoin Contraindicated
- Cabotegravir + Phenytoin Contraindicated
- Doravirine + Phenytoin Contraindicated
- Elbasvir / grazoprevir + Phenytoin Contraindicated
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Phenytoin Contraindicated
Frequently asked questions
Can I take Ivermectin with Phenytoin?
MediHelp rates the interaction as minor. Ivermectin and Phenytoin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Phenytoin is an enzyme inducer, and it may modestly lower ivermectin exposure through CYP3A4 induction. This is theoretical and not well documented, so antiparasitic efficacy is unlikely to be meaningfully affected.
How serious is the interaction between Ivermectin and Phenytoin?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No dose change is needed; assess treatment response and repeat ivermectin if parasitological cure is not achieved.
What other medicines interact with Ivermectin?
MediHelp also lists interactions of Ivermectin with, for example, Erdafitinib, Lasmiditan, Quinidine. The full list is on the Ivermectin page.
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