Drug interactions
Phenobarbitone + Sapropterin
Severity: Moderate
Phenobarbitone and Sapropterin: 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 may interfere with folate-dependent pathways that support tetrahydrobiopterin (BH4) availability. This could reduce sapropterin effect and allow blood phenylalanine to rise in patients with phenylketonuria.
What this interaction means in plain words
Phenobarbitone and Sapropterin 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.
Phenobarbitone belongs to Central Nervous System; Sapropterin belongs to Miscellaneous.
Why it happens
Interference with folate metabolism may lower BH4 availability, though the mechanism is not firmly established for phenobarbital.
What to do
Check blood phenylalanine more frequently after starting or stopping phenobarbital. Adjust the sapropterin dose according to the phenylalanine response.
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 Sapropterin
- Avanafil + Sapropterin Moderate
- Carbidopa-entacapone-levodopa + Sapropterin Moderate
- Carbidopa-levodopa + Sapropterin Moderate
- Levodopa + Sapropterin Moderate
- Methotrexate + Sapropterin Moderate
- Pyrimethamine + Sapropterin Moderate
Other interactions of Phenobarbitone
- Cabotegravir + Phenobarbitone Contraindicated
- Doravirine + Phenobarbitone Contraindicated
- Isavuconazole + Phenobarbitone Contraindicated
- Darolutamide + Phenobarbitone Major
- Finerenone + Phenobarbitone Major
- Ivacaftor + Phenobarbitone Major
Frequently asked questions
Can I take Phenobarbitone with Sapropterin?
MediHelp rates the interaction as moderate. Phenobarbitone and Sapropterin 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 may interfere with folate-dependent pathways that support tetrahydrobiopterin (BH4) availability. This could reduce sapropterin effect and allow blood phenylalanine to rise in patients with phenylketonuria.
How serious is the interaction between Phenobarbitone and Sapropterin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check blood phenylalanine more frequently after starting or stopping phenobarbital. Adjust the sapropterin dose according to the phenylalanine response.
What other medicines interact with Sapropterin?
MediHelp also lists interactions of Sapropterin with, for example, Avanafil, Carbidopa-entacapone-levodopa, Carbidopa-levodopa. The full list is on the Sapropterin page.
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