Drug interactions
Fentanyl + Promethazine
Severity: Major
Fentanyl and Promethazine: major 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
The concurrent use of promethazine and fentanyl can lead to enhanced sedation and respiratory depression, increasing the risk of serious adverse effects. Patients may experience profound drowsiness, impaired cognitive function, and decreased respiratory drive, which can be particularly dangerous in vulnerable populations.
What this interaction means in plain words
Fentanyl and Promethazine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Fentanyl belongs to Musculoskeletal; Promethazine belongs to Respiratory.
Why it happens
Both promethazine and fentanyl are central nervous system depressants, and their combined effects can potentiate sedation and respiratory suppression.
What to do
Patients receiving both medications should be closely monitored for signs of excessive sedation and respiratory distress. Consider alternative therapies if possible, and if co-administration is necessary, use the lowest effective doses and monitor the patient closely.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Promethazine
- Cabergoline + Promethazine Contraindicated
- Dopamine + Promethazine Contraindicated
- Ibutilide + Promethazine Contraindicated
- Pimozide + Promethazine Contraindicated
- Promethazine + Thioridazine Contraindicated
- Alfentanil + Promethazine Major
Other interactions of Fentanyl
- Alvimopan + Fentanyl Contraindicated
- Fentanyl + Isocarboxazid Contraindicated
- Fentanyl + Olanzapine / samidorphan Contraindicated
- Fentanyl + Phenelzine Contraindicated
- Fentanyl + Tranylcypromine Contraindicated
- Alfentanil + Fentanyl Major
Frequently asked questions
Can I take Fentanyl with Promethazine?
MediHelp rates the interaction as major. Fentanyl and Promethazine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. The concurrent use of promethazine and fentanyl can lead to enhanced sedation and respiratory depression, increasing the risk of serious adverse effects. Patients may experience profound drowsiness, impaired cognitive function, and decreased respiratory drive, which can be particularly dangerous in vulnerable populations.
How serious is the interaction between Fentanyl and Promethazine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Patients receiving both medications should be closely monitored for signs of excessive sedation and respiratory distress. Consider alternative therapies if possible, and if co-administration is necessary, use the lowest effective doses and monitor the patient closely.
What other medicines interact with Promethazine?
MediHelp also lists interactions of Promethazine with, for example, Cabergoline, Dopamine, Ibutilide. The full list is on the Promethazine page.
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