Drug interactions
Dexamethasone-neomycin-polymyxin + Phenobarbital
Severity: Moderate
Dexamethasone-neomycin-polymyxin and Phenobarbital: 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
Phenobarbital is an enzyme inducer that can reduce dexamethasone exposure and weaken its anti-inflammatory or antiemetic effect. The effect is relevant for systemic steroid therapy and unlikely with topical products.
What this interaction means in plain words
Dexamethasone-neomycin-polymyxin and Phenobarbital 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.
Why it happens
Induction of CYP3A4 and P-glycoprotein by phenobarbital increases dexamethasone clearance.
What to do
With systemic dexamethasone, monitor therapeutic response and raise the dose if needed. Consider a non-inducing anticonvulsant if long-term steroid therapy is required.
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
Frequently asked questions
Can I take Dexamethasone-neomycin-polymyxin with Phenobarbital?
MediHelp rates the interaction as moderate. Dexamethasone-neomycin-polymyxin and Phenobarbital 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. Phenobarbital is an enzyme inducer that can reduce dexamethasone exposure and weaken its anti-inflammatory or antiemetic effect. The effect is relevant for systemic steroid therapy and unlikely with topical products.
How serious is the interaction between Dexamethasone-neomycin-polymyxin and Phenobarbital?
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 therapeutic response and raise the dose if needed. Consider a non-inducing anticonvulsant if long-term steroid therapy is required.
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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