Drug interactions
Diazoxide + Phenytoin
Severity: Moderate
Diazoxide 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
Oral diazoxide has been reported to lower serum phenytoin concentrations, which may reduce seizure control. Phenytoin may also blunt the hyperglycemic effect of diazoxide, reducing its efficacy in hypoglycemia.
What this interaction means in plain words
Diazoxide 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.
Diazoxide belongs to Miscellaneous; Phenytoin belongs to Central Nervous System.
Why it happens
Diazoxide may increase hepatic metabolism or alter protein binding of phenytoin, though the mechanism is not clearly established.
What to do
Monitor serum phenytoin (preferably free) concentrations and seizure control, and monitor blood glucose when either drug is started, adjusted 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 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
Other interactions of Diazoxide
Frequently asked questions
Can I take Diazoxide with Phenytoin?
MediHelp rates the interaction as moderate. Diazoxide 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. Oral diazoxide has been reported to lower serum phenytoin concentrations, which may reduce seizure control. Phenytoin may also blunt the hyperglycemic effect of diazoxide, reducing its efficacy in hypoglycemia.
How serious is the interaction between Diazoxide 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 serum phenytoin (preferably free) concentrations and seizure control, and monitor blood glucose when either drug is started, adjusted or stopped.
What other medicines interact with Phenytoin?
MediHelp also lists interactions of Phenytoin with, for example, Artemether / lumefantrine, Bictegravir, Cabotegravir. The full list is on the Phenytoin page.
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