Drug interactions
Chlorpheniramine + Diphenoxylate
Severity: Moderate
Chlorpheniramine and Diphenoxylate: 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
Diphenoxylate is an opioid and, with a sedating antihistamine, can add to drowsiness and CNS depression. Additive anticholinergic effects may raise the risk of ileus or urinary retention, especially in children and older adults.
What this interaction means in plain words
Chlorpheniramine and Diphenoxylate 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; Diphenoxylate 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 oversedation and for signs of ileus 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 Diphenoxylate
Frequently asked questions
Can I take Chlorpheniramine with Diphenoxylate?
MediHelp rates the interaction as moderate. Chlorpheniramine and Diphenoxylate 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. Diphenoxylate is an opioid and, with a sedating antihistamine, can add to drowsiness and CNS depression. Additive anticholinergic effects may raise the risk of ileus or urinary retention, especially in children and older adults.
How serious is the interaction between Chlorpheniramine and Diphenoxylate?
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 oversedation and for signs of ileus 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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