Drug interactions
Buprenorphine long-acting + Diphenhydramine
Severity: Moderate
Buprenorphine long-acting and Diphenhydramine: moderate interaction.
Last updated
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
Buprenorphine given as a long-acting injection is an opioid, and diphenhydramine is a sedating antihistamine. The combination can add to drowsiness and psychomotor impairment and can contribute to respiratory depression. Because the injection cannot be withdrawn quickly, the effect may last for some time.
What this interaction means in plain words
Buprenorphine long-acting and Diphenhydramine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Additive central nervous system depression through opioid receptor agonism and central histamine H1 blockade.
What to do
Monitor for excessive sedation and slowed breathing, and avoid regular use of sedating antihistamines where possible. Counsel patients not to drive or use machinery if drowsy.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Diphenhydramine
Frequently asked questions
Can I take Buprenorphine long-acting with Diphenhydramine?
MediHelp rates the interaction as moderate. Buprenorphine long-acting and Diphenhydramine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Buprenorphine given as a long-acting injection is an opioid, and diphenhydramine is a sedating antihistamine. The combination can add to drowsiness and psychomotor impairment and can contribute to respiratory depression. Because the injection cannot be withdrawn quickly, the effect may last for some time.
How serious is the interaction between Buprenorphine long-acting and Diphenhydramine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for excessive sedation and slowed breathing, and avoid regular use of sedating antihistamines where possible. Counsel patients not to drive or use machinery if drowsy.
What other medicines interact with Diphenhydramine?
MediHelp also lists interactions of Diphenhydramine with, for example, Alfentanil, Belladonna and opium, Benzhydrocodone / acetaminophen. The full list is on the Diphenhydramine page.
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