Drug interactions
Chlorpheniramine + Levorphanol
Severity: Major
Chlorpheniramine 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
Opioids such as levorphanol combined with sedating antihistamines can cause additive sedation and respiratory depression. Impaired alertness and slowed breathing are more likely in older or opioid-naive patients.
What this interaction means in plain words
Chlorpheniramine 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 mu-opioid agonism and H1-antihistamine sedation.
What to do
Use the lowest effective doses and monitor sedation and respiratory rate. Consider a non-sedating antihistamine.
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 Chlorpheniramine
Frequently asked questions
Can I take Chlorpheniramine with Levorphanol?
MediHelp rates the interaction as major. Chlorpheniramine 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. Opioids such as levorphanol combined with sedating antihistamines can cause additive sedation and respiratory depression. Impaired alertness and slowed breathing are more likely in older or opioid-naive patients.
How serious is the interaction between Chlorpheniramine 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: Use the lowest effective doses and monitor sedation and respiratory rate. Consider a non-sedating antihistamine.
What other medicines interact with Chlorpheniramine?
MediHelp also lists interactions of Chlorpheniramine with, for example, Belladonna and opium, Benzhydrocodone / acetaminophen, Brexanolone. The full list is on the Chlorpheniramine page.
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