Drug interactions
Chlorpheniramine + Difenoxin
Severity: Moderate
Chlorpheniramine and Difenoxin: 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
Difenoxin is an opioid antidiarrheal metabolite related to diphenoxylate, and with a sedating antihistamine it can increase drowsiness and CNS depression. Anticholinergic effects on the gut may also be additive.
What this interaction means in plain words
Chlorpheniramine and Difenoxin 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.
Chlorpheniramine belongs to Respiratory; Difenoxin belongs to Gastrointestinal Tract.
Why it happens
Additive CNS depression from opioid activity and sedating H1 blockade, with additive antimuscarinic effects.
What to do
Counsel about sedation and avoid alcohol and other depressants. Monitor for excessive drowsiness, constipation or urinary retention.
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 Chlorpheniramine
Other interactions of Difenoxin
Frequently asked questions
Can I take Chlorpheniramine with Difenoxin?
MediHelp rates the interaction as moderate. Chlorpheniramine and Difenoxin 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. Difenoxin is an opioid antidiarrheal metabolite related to diphenoxylate, and with a sedating antihistamine it can increase drowsiness and CNS depression. Anticholinergic effects on the gut may also be additive.
How serious is the interaction between Chlorpheniramine and Difenoxin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Counsel about sedation and avoid alcohol and other depressants. Monitor for excessive drowsiness, constipation or urinary retention.
What other medicines interact with Chlorpheniramine?
MediHelp also lists interactions of Chlorpheniramine with, for example, Belladonna and opium, Benzhydrocodone / acetaminophen, Brexanolone. The full list is on the Chlorpheniramine page.
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