Drug interactions
Bosentan + Phenobarbital
Severity: Moderate
Bosentan 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
Phenobarbital is a potent inducer of CYP3A4 and CYP2C9 and is expected to lower plasma bosentan concentrations. This may reduce control of pulmonary arterial hypertension. Bosentan can also induce metabolism of other drugs, so the net effect is variable.
What this interaction means in plain words
Bosentan 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
Phenobarbital induces CYP3A4 and CYP2C9, increasing hepatic and intestinal metabolism of bosentan.
What to do
Monitor for loss of efficacy of bosentan and for changes in liver enzymes. Reassess bosentan response when phenobarbital is started, adjusted or withdrawn.
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 Bosentan
- Bosentan + Cyclosporin Contraindicated
- Bosentan + Glibenclamide Contraindicated
- Bosentan + Glyburide-metformin Contraindicated
- Bosentan + Lonafarnib Contraindicated
- Bosentan + Sparsentan Contraindicated
- Artemether / lumefantrine + Bosentan Major
Frequently asked questions
Can I take Bosentan with Phenobarbital?
MediHelp rates the interaction as moderate. Bosentan 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. Phenobarbital is a potent inducer of CYP3A4 and CYP2C9 and is expected to lower plasma bosentan concentrations. This may reduce control of pulmonary arterial hypertension. Bosentan can also induce metabolism of other drugs, so the net effect is variable.
How serious is the interaction between Bosentan 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 for loss of efficacy of bosentan and for changes in liver enzymes. Reassess bosentan response when phenobarbital is started, adjusted or withdrawn.
What other medicines interact with Bosentan?
MediHelp also lists interactions of Bosentan with, for example, Cyclosporin, Glibenclamide, Glyburide-metformin. The full list is on the Bosentan page.
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