Drug interactions
Belladonna and opium + Chlorpheniramine
Severity: Major
Belladonna and opium and Chlorpheniramine: major 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
The opium component adds CNS and respiratory depression to the sedation of chlorpheniramine, and belladonna adds anticholinergic burden. The combination can cause marked drowsiness, constipation, urinary retention and confusion.
What this interaction means in plain words
Belladonna and opium and Chlorpheniramine 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 opioid CNS and respiratory depression plus additive anticholinergic effects.
What to do
Avoid if possible; otherwise use the lowest doses and monitor sedation, respiration and anticholinergic effects. Use a non-sedating antihistamine instead.
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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Other interactions of Chlorpheniramine
- Benzhydrocodone / acetaminophen + Chlorpheniramine Major
- Brexanolone + Chlorpheniramine Major
- Buprenorphine long-acting + Chlorpheniramine Major
- Buprenorphine subdermal implant + Chlorpheniramine Major
- Buprenorphine transdermal + Chlorpheniramine Major
- Calcium / magnesium / potassium / sodium oxybates + Chlorpheniramine Major
Frequently asked questions
Can I take Belladonna and opium with Chlorpheniramine?
MediHelp rates the interaction as major. Belladonna and opium and Chlorpheniramine 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. The opium component adds CNS and respiratory depression to the sedation of chlorpheniramine, and belladonna adds anticholinergic burden. The combination can cause marked drowsiness, constipation, urinary retention and confusion.
How serious is the interaction between Belladonna and opium and Chlorpheniramine?
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 if possible; otherwise use the lowest doses and monitor sedation, respiration and anticholinergic effects. Use a non-sedating antihistamine instead.
What other medicines interact with Chlorpheniramine?
MediHelp also lists interactions of Chlorpheniramine with, for example, Benzhydrocodone / acetaminophen, Brexanolone, Buprenorphine long-acting. The full list is on the Chlorpheniramine page.
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