Drug interactions
Fentanyl iontophoretic transdermal system + Promethazine
Severity: Major
Fentanyl iontophoretic transdermal system 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 combination of promethazine and the fentanyl iontophoretic transdermal system can lead to enhanced sedation and respiratory depression. This increased sedative effect may pose significant risks, particularly in vulnerable populations or those with pre-existing respiratory conditions.
What this interaction means in plain words
Fentanyl iontophoretic transdermal system 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.
Why it happens
Both drugs have central nervous system depressant effects, which can synergistically increase sedation and the risk of respiratory compromise when used together.
What to do
Patients receiving both medications should be closely monitored for signs of excessive sedation and respiratory depression. Consider alternative therapies if possible, especially in patients with a history of respiratory issues or those requiring high doses.
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
Frequently asked questions
Can I take Fentanyl iontophoretic transdermal system with Promethazine?
MediHelp rates the interaction as major. Fentanyl iontophoretic transdermal system 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 combination of promethazine and the fentanyl iontophoretic transdermal system can lead to enhanced sedation and respiratory depression. This increased sedative effect may pose significant risks, particularly in vulnerable populations or those with pre-existing respiratory conditions.
How serious is the interaction between Fentanyl iontophoretic transdermal system 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 depression. Consider alternative therapies if possible, especially in patients with a history of respiratory issues or those requiring high doses.
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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