Drug interactions
Clemastine + Levorphanol
Severity: Major
Clemastine and Levorphanol: 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
Combining an opioid with a sedating antihistamine increases drowsiness, dizziness and psychomotor impairment. Concurrent CNS depressants with opioids can also increase the risk of respiratory depression.
What this interaction means in plain words
Clemastine and Levorphanol 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 CNS and respiratory depression from opioid agonism and central H1 antagonism.
What to do
Avoid the combination where possible, or use the lowest effective doses and monitor sedation and respiratory rate. Counsel the patient about driving and alcohol.
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 Levorphanol?
MediHelp rates the interaction as major. Clemastine and Levorphanol 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. Combining an opioid with a sedating antihistamine increases drowsiness, dizziness and psychomotor impairment. Concurrent CNS depressants with opioids can also increase the risk of respiratory depression.
How serious is the interaction between Clemastine and Levorphanol?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination where possible, or use the lowest effective doses and monitor sedation and respiratory rate. Counsel the patient about driving and alcohol.
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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