Drug interactions
Diamorphine + Doxylamine
Severity: Major
Diamorphine and Doxylamine: major interaction.
Last updated Sources: Base de donnees publique des medicaments (France)
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
Diamorphine (heroin) is a potent opioid and doxylamine is a sedating antihistamine. Together they can cause deep sedation, respiratory depression, coma and death.
What this interaction means in plain words
Diamorphine and Doxylamine 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 via opioid receptor agonism and central H1 antagonism.
What to do
Avoid combination where feasible; if both are necessary use the lowest doses and monitor sedation and breathing closely. Consider non-sedating alternatives for allergy or sleep.
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 Diamorphine with Doxylamine?
MediHelp rates the interaction as major. Diamorphine and Doxylamine 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. Diamorphine (heroin) is a potent opioid and doxylamine is a sedating antihistamine. Together they can cause deep sedation, respiratory depression, coma and death.
How serious is the interaction between Diamorphine and Doxylamine?
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 combination where feasible; if both are necessary use the lowest doses and monitor sedation and breathing closely. Consider non-sedating alternatives for allergy or sleep.
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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