Answer
Phenobarbital sodium can reduce methadone levels during concurrent use, with withdrawal symptoms reported when phenobarbital is added to methadone maintenance treatment; an increase in methadone dosage may be necessary.
Sources for this answer
- Phenobarbital Sodium 30mg/ml InjectionMartindale Pharma, an Ethypharm Group Company · emc · SmPC §4.5 Interaction with other medicinal products · Version 5Document updated
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