Drug interactions
Guselkumab + Phenobarbital
Severity: Minor
Guselkumab and Phenobarbital: 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
Chronic inflammation suppresses CYP450 expression, and IL-23 blockade may restore enzyme activity. Phenobarbital and its metabolites could be affected, though the effect is expected to be small. Phenobarbital has a narrow therapeutic range, so changes may matter.
What this interaction means in plain words
Guselkumab and Phenobarbital have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Why it happens
Cytokine modulation by IL-23 inhibition may normalize suppressed CYP450 activity, potentially altering phenobarbital clearance.
What to do
Monitor seizure control and sedation, and check phenobarbital levels when guselkumab is started or stopped. Adjust the dose only if needed.
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 Guselkumab
- Adenovirus types 4 and 7 live + Guselkumab Major
- Bcg vaccine live + Guselkumab Major
- Guselkumab + Influenza virus vaccine quadrivalent intranasal Major
- Guselkumab + Measles mumps and rubella vaccine live Major
- Guselkumab + Measles mumps rubella and varicella vaccine live Major
- Guselkumab + Measles vaccine Major
Frequently asked questions
Can I take Guselkumab with Phenobarbital?
MediHelp rates the interaction as minor. Guselkumab and Phenobarbital have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Chronic inflammation suppresses CYP450 expression, and IL-23 blockade may restore enzyme activity. Phenobarbital and its metabolites could be affected, though the effect is expected to be small. Phenobarbital has a narrow therapeutic range, so changes may matter.
How serious is the interaction between Guselkumab and Phenobarbital?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor seizure control and sedation, and check phenobarbital levels when guselkumab is started or stopped. Adjust the dose only if needed.
What other medicines interact with Guselkumab?
MediHelp also lists interactions of Guselkumab with, for example, Adenovirus types 4 and 7 live, Bcg vaccine live, Influenza virus vaccine quadrivalent intranasal. The full list is on the Guselkumab page.
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