Drug interactions
Fosphenytoin + Orlistat
Severity: Minor
Fosphenytoin and Orlistat: 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
Orlistat may reduce antiepileptic drug exposure and has been linked to loss of seizure control. Fosphenytoin is given parenterally and converted to phenytoin, so absorption is not relevant, though oral phenytoin is.
What this interaction means in plain words
Fosphenytoin and Orlistat have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Fosphenytoin belongs to Central Nervous System; Orlistat belongs to Miscellaneous.
Why it happens
Orlistat's absorption effect applies to oral phenytoin, not to injected fosphenytoin, so a direct interaction is unlikely.
What to do
No action is generally needed for parenteral fosphenytoin; if transitioned to oral phenytoin, monitor phenytoin levels and seizure control.
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 Orlistat
- Cyclosporin + Orlistat Major
- Orlistat + Triheptanoin Major
- Amiodarone + Orlistat Moderate
- Beta carotene + Orlistat Moderate
- Carbamazepine + Orlistat Moderate
- Cholecalciferol + Orlistat Moderate
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 Orlistat?
MediHelp rates the interaction as minor. Fosphenytoin and Orlistat have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Orlistat may reduce antiepileptic drug exposure and has been linked to loss of seizure control. Fosphenytoin is given parenterally and converted to phenytoin, so absorption is not relevant, though oral phenytoin is.
How serious is the interaction between Fosphenytoin and Orlistat?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No action is generally needed for parenteral fosphenytoin; if transitioned to oral phenytoin, monitor phenytoin levels and seizure control.
What other medicines interact with Orlistat?
MediHelp also lists interactions of Orlistat with, for example, Cyclosporin, Triheptanoin, Amiodarone. The full list is on the Orlistat page.
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