Drug interactions
Dexamethasone-neomycin-polymyxin + Phenytoin
Severity: Moderate
Dexamethasone-neomycin-polymyxin 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
Phenytoin induces CYP3A4 and may substantially lower dexamethasone exposure. Dexamethasone may also alter phenytoin levels unpredictably.
What this interaction means in plain words
Dexamethasone-neomycin-polymyxin 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.
Dexamethasone-neomycin-polymyxin belongs to Anti Bacterial; Phenytoin belongs to Central Nervous System.
Why it happens
Phenytoin induces CYP3A4 and P-glycoprotein, increasing dexamethasone clearance.
What to do
With systemic dexamethasone, monitor response and raise the dose if needed. Check phenytoin levels when steroids are started or stopped.
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 Dexamethasone-neomycin-polymyxin
- Dexamethasone-neomycin-polymyxin + Ketorolac Major
- Dexamethasone-neomycin-polymyxin + Lapatinib Major
- Dexamethasone-neomycin-polymyxin + Levofloxacin Major
- Dexamethasone-neomycin-polymyxin + Mifepristone Major
- Dexamethasone-neomycin-polymyxin + Moxifloxacin Major
- Aldesleukin + Dexamethasone-neomycin-polymyxin 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 Dexamethasone-neomycin-polymyxin with Phenytoin?
MediHelp rates the interaction as moderate. Dexamethasone-neomycin-polymyxin 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. Phenytoin induces CYP3A4 and may substantially lower dexamethasone exposure. Dexamethasone may also alter phenytoin levels unpredictably.
How serious is the interaction between Dexamethasone-neomycin-polymyxin 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: With systemic dexamethasone, monitor response and raise the dose if needed. Check phenytoin levels when steroids are started or stopped.
What other medicines interact with Dexamethasone-neomycin-polymyxin?
MediHelp also lists interactions of Dexamethasone-neomycin-polymyxin with, for example, Ketorolac, Lapatinib, Levofloxacin. The full list is on the Dexamethasone-neomycin-polymyxin page.
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