Drug interactions
Clemastine + Fentanyl iontophoretic transdermal system
Severity: Major
Clemastine and Fentanyl iontophoretic transdermal system: major interaction.
Last updated Sources: US FDA label
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
Fentanyl is a potent opioid and clemastine is a sedating antihistamine. Combined use increases sedation and may add to respiratory depression risk.
What this interaction means in plain words
Clemastine and Fentanyl iontophoretic transdermal system 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
Additive central nervous system and respiratory depression.
What to do
Monitor sedation and respiratory rate, especially after starting or increasing doses. Prefer a non-sedating antihistamine when possible.
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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References
Other interactions of Clemastine
Frequently asked questions
Can I take Clemastine with Fentanyl iontophoretic transdermal system?
MediHelp rates the interaction as major. Clemastine and Fentanyl iontophoretic transdermal system 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 is a potent opioid and clemastine is a sedating antihistamine. Combined use increases sedation and may add to respiratory depression risk.
How serious is the interaction between Clemastine and Fentanyl iontophoretic transdermal system?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor sedation and respiratory rate, especially after starting or increasing doses. Prefer a non-sedating antihistamine when possible.
What other medicines interact with Clemastine?
MediHelp also lists interactions of Clemastine with, for example, Alfentanil, Benzhydrocodone / acetaminophen, Buprenorphine buccal. The full list is on the Clemastine page.
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