Drug interactions
Doxylamine + Levorphanol
Severity: Major
Doxylamine 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
Levorphanol is a potent opioid, and doxylamine is a sedating antihistamine. Combined, they can cause profound sedation and respiratory depression, particularly in older or opioid-naive patients.
What this interaction means in plain words
Doxylamine 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 H1 antihistamine sedation.
What to do
Avoid concurrent use where possible; if needed, use the lowest effective doses and monitor sedation and respiratory rate. Counsel against alcohol and driving.
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 Doxylamine
Frequently asked questions
Can I take Doxylamine with Levorphanol?
MediHelp rates the interaction as major. Doxylamine 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. Levorphanol is a potent opioid, and doxylamine is a sedating antihistamine. Combined, they can cause profound sedation and respiratory depression, particularly in older or opioid-naive patients.
How serious is the interaction between Doxylamine 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 concurrent use where possible; if needed, use the lowest effective doses and monitor sedation and respiratory rate. Counsel against alcohol and driving.
What other medicines interact with Doxylamine?
MediHelp also lists interactions of Doxylamine with, for example, Belladonna and opium, Benzhydrocodone / acetaminophen, Brexanolone. The full list is on the Doxylamine page.
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