Drug interactions
Fosphenytoin + Methylphenidate
Severity: Moderate
Fosphenytoin and Methylphenidate: 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
Case reports and labeling suggest methylphenidate may raise phenytoin concentrations, leading to toxicity such as nystagmus, ataxia and drowsiness. The reverse can happen when methylphenidate is stopped, with phenytoin levels falling.
What this interaction means in plain words
Fosphenytoin and Methylphenidate 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.
Fosphenytoin belongs to Central Nervous System; Methylphenidate belongs to Central Nervous System.
Why it happens
Possible inhibition of phenytoin hepatic metabolism by methylphenidate; the mechanism is not firmly established.
What to do
Monitor serum phenytoin concentrations and clinical signs of toxicity when starting, changing or stopping methylphenidate, and adjust the fosphenytoin dose accordingly.
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 Methylphenidate
- Isocarboxazid + Methylphenidate Contraindicated
- Linezolid + Methylphenidate Contraindicated
- Methylphenidate + Phenelzine Contraindicated
- Methylphenidate + Procarbazine Contraindicated
- Methylphenidate + Rasagiline Contraindicated
- Methylphenidate + Safinamide Contraindicated
Other interactions of Fosphenytoin
- Dronedarone + Fosphenytoin Contraindicated
- Fosphenytoin + Ledipasvir-sofosbuvir Contraindicated
- Fosphenytoin + Lorlatinib Contraindicated
- Fosphenytoin + Lurasidone Contraindicated
- Fosphenytoin + Ranolazine Contraindicated
- Fosphenytoin + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
Frequently asked questions
Can I take Fosphenytoin with Methylphenidate?
MediHelp rates the interaction as moderate. Fosphenytoin and Methylphenidate 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. Case reports and labeling suggest methylphenidate may raise phenytoin concentrations, leading to toxicity such as nystagmus, ataxia and drowsiness. The reverse can happen when methylphenidate is stopped, with phenytoin levels falling.
How serious is the interaction between Fosphenytoin and Methylphenidate?
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 concentrations and clinical signs of toxicity when starting, changing or stopping methylphenidate, and adjust the fosphenytoin dose accordingly.
What other medicines interact with Methylphenidate?
MediHelp also lists interactions of Methylphenidate with, for example, Isocarboxazid, Linezolid, Phenelzine. The full list is on the Methylphenidate page.
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