Drug interactions
Fentanyl + Glycerol phenylbutyrate
Severity: Minor
Fentanyl and Glycerol phenylbutyrate: 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
Glycerol phenylbutyrate is a weak CYP3A4 inducer and may lower fentanyl concentrations. This could reduce analgesia, particularly in patients whose pain is well controlled on a stable dose.
What this interaction means in plain words
Fentanyl and Glycerol phenylbutyrate have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Fentanyl belongs to Musculoskeletal; Glycerol phenylbutyrate belongs to Miscellaneous.
Why it happens
Weak induction of CYP3A4 increases the metabolic clearance of fentanyl.
What to do
Monitor pain control and titrate fentanyl as needed. Recheck the dose if glycerol phenylbutyrate is stopped.
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 Fentanyl
- Alvimopan + Fentanyl Contraindicated
- Fentanyl + Isocarboxazid Contraindicated
- Fentanyl + Olanzapine / samidorphan Contraindicated
- Fentanyl + Phenelzine Contraindicated
- Fentanyl + Tranylcypromine Contraindicated
- Alfentanil + Fentanyl Major
Other interactions of Glycerol phenylbutyrate
- Dexamethasone + Glycerol phenylbutyrate Major
- Glycerol phenylbutyrate + Sodium valproate Major
- Glycerol phenylbutyrate + Valproic acid Major
- Cyclosporin + Glycerol phenylbutyrate Moderate
- Dexamethasone-neomycin-polymyxin + Glycerol phenylbutyrate Moderate
- Dexamethasone-tobramycin + Glycerol phenylbutyrate Moderate
Frequently asked questions
Can I take Fentanyl with Glycerol phenylbutyrate?
MediHelp rates the interaction as minor. Fentanyl and Glycerol phenylbutyrate have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Glycerol phenylbutyrate is a weak CYP3A4 inducer and may lower fentanyl concentrations. This could reduce analgesia, particularly in patients whose pain is well controlled on a stable dose.
How serious is the interaction between Fentanyl and Glycerol phenylbutyrate?
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 pain control and titrate fentanyl as needed. Recheck the dose if glycerol phenylbutyrate is stopped.
What other medicines interact with Fentanyl?
MediHelp also lists interactions of Fentanyl with, for example, Alvimopan, Isocarboxazid, Olanzapine / samidorphan. The full list is on the Fentanyl page.
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