Drug interactions
Orlistat + Phenobarbital
Severity: Moderate
Orlistat 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
Orlistat may reduce antiepileptic exposure, and breakthrough seizures have been described with orlistat in patients on anticonvulsants. Phenobarbital-specific data are limited.
What this interaction means in plain words
Orlistat 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
Possible reduced gut absorption of oral phenobarbital due to orlistat-induced fat malabsorption; mechanism not firmly established.
What to do
Monitor seizure frequency and phenobarbital serum levels after starting or stopping orlistat. Separate doses by a few hours.
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 Orlistat
- Cyclosporine + Orlistat Major
- Cyclosporin + Orlistat Major
- Orlistat + Triheptanoin Major
- Amiodarone + Orlistat Moderate
- Beta carotene + Orlistat Moderate
- Carbamazepine + Orlistat Moderate
Frequently asked questions
Can I take Orlistat with Phenobarbital?
MediHelp rates the interaction as moderate. Orlistat 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. Orlistat may reduce antiepileptic exposure, and breakthrough seizures have been described with orlistat in patients on anticonvulsants. Phenobarbital-specific data are limited.
How serious is the interaction between Orlistat 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: Monitor seizure frequency and phenobarbital serum levels after starting or stopping orlistat. Separate doses by a few hours.
What other medicines interact with Orlistat?
MediHelp also lists interactions of Orlistat with, for example, Cyclosporine, Cyclosporin, Triheptanoin. The full list is on the Orlistat page.
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