Drug interactions
Diamorphine + Metaxalone
Severity: Major
Diamorphine and Metaxalone: 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
Both drugs depress the central nervous system, so together they can cause greater drowsiness, impaired psychomotor performance and, with higher opioid doses, respiratory depression. Elderly or opioid-naive patients are at the greatest risk.
What this interaction means in plain words
Diamorphine and Metaxalone 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 depression between a sedating muscle relaxant and an opioid agonist.
What to do
Use the lowest effective doses and monitor for excessive sedation and slowed breathing, especially when starting or increasing either drug. Counsel patients not to drive or operate machinery.
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 Metaxalone
Frequently asked questions
Can I take Diamorphine with Metaxalone?
MediHelp rates the interaction as major. Diamorphine and Metaxalone 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. Both drugs depress the central nervous system, so together they can cause greater drowsiness, impaired psychomotor performance and, with higher opioid doses, respiratory depression. Elderly or opioid-naive patients are at the greatest risk.
How serious is the interaction between Diamorphine and Metaxalone?
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 for excessive sedation and slowed breathing, especially when starting or increasing either drug. Counsel patients not to drive or operate machinery.
What other medicines interact with Metaxalone?
MediHelp also lists interactions of Metaxalone with, for example, Alfentanil, Belladonna and opium, Benzhydrocodone / acetaminophen. The full list is on the Metaxalone page.
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