Drug interactions
Dexmethylphenidate + Phenytoin
Severity: Minor
Dexmethylphenidate 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
Methylphenidate-type stimulants have been reported to raise phenytoin concentrations in a small number of cases. If this occurs, phenytoin toxicity such as nystagmus, ataxia and drowsiness could develop. The effect is infrequent and mostly documented with the related drug methylphenidate.
What this interaction means in plain words
Dexmethylphenidate 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.
Dexmethylphenidate belongs to Central Nervous System; Phenytoin belongs to Central Nervous System.
Why it happens
Methylphenidate may inhibit hepatic metabolism of phenytoin, although the mechanism is not firmly established.
What to do
Monitor for signs of phenytoin toxicity and check serum phenytoin levels if symptoms appear or when dexmethylphenidate is started or stopped.
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 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 Dexmethylphenidate
- Dexmethylphenidate + Isocarboxazid Contraindicated
- Dexmethylphenidate + Linezolid Contraindicated
- Dexmethylphenidate + Phenelzine Contraindicated
- Dexmethylphenidate + Procarbazine Contraindicated
- Dexmethylphenidate + Rasagiline Contraindicated
- Dexmethylphenidate + Safinamide Contraindicated
Frequently asked questions
Can I take Dexmethylphenidate with Phenytoin?
MediHelp rates the interaction as minor. Dexmethylphenidate 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. Methylphenidate-type stimulants have been reported to raise phenytoin concentrations in a small number of cases. If this occurs, phenytoin toxicity such as nystagmus, ataxia and drowsiness could develop. The effect is infrequent and mostly documented with the related drug methylphenidate.
How serious is the interaction between Dexmethylphenidate 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: Monitor for signs of phenytoin toxicity and check serum phenytoin levels if symptoms appear or when dexmethylphenidate is started 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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