Drug interactions
Ofloxacin + Phenytoin
Severity: Moderate
Ofloxacin and Phenytoin: 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
Fluoroquinolones have been reported to alter phenytoin concentrations, with both lower and higher levels described. Either subtherapeutic levels with seizure breakthrough or toxicity may occur.
What this interaction means in plain words
Ofloxacin and Phenytoin 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.
Ofloxacin belongs to Anti Bacterial; Phenytoin belongs to Central Nervous System.
Why it happens
The mechanism is not established.
What to do
Monitor phenytoin concentrations and clinical response when starting or stopping ofloxacin. Adjust the phenytoin dose according to levels.
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 Ofloxacin
- Ofloxacin + Thioridazine Contraindicated
- Adagrasib + Ofloxacin Major
- Amiodarone + Ofloxacin Major
- Amisulpride + Ofloxacin Major
- Anagrelide + Ofloxacin Major
- Arsenic trioxide + Ofloxacin Major
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 Ofloxacin with Phenytoin?
MediHelp rates the interaction as moderate. Ofloxacin and Phenytoin 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. Fluoroquinolones have been reported to alter phenytoin concentrations, with both lower and higher levels described. Either subtherapeutic levels with seizure breakthrough or toxicity may occur.
How serious is the interaction between Ofloxacin and Phenytoin?
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 phenytoin concentrations and clinical response when starting or stopping ofloxacin. Adjust the phenytoin dose according to levels.
What other medicines interact with Ofloxacin?
MediHelp also lists interactions of Ofloxacin with, for example, Thioridazine, Adagrasib, Amiodarone. The full list is on the Ofloxacin page.
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