Drug interactions
Chlorpheniramine + Istradefylline
Severity: Minor
Chlorpheniramine and Istradefylline: minor 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
At higher doses istradefylline weakly inhibits CYP3A4 and may increase exposure to CYP3A4 substrates like chlorpheniramine. Sedation and anticholinergic effects may therefore be more pronounced.
What this interaction means in plain words
Chlorpheniramine and Istradefylline have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Chlorpheniramine belongs to Respiratory; Istradefylline belongs to Central Nervous System.
Why it happens
Inhibition of CYP3A4 by istradefylline at higher doses reduces chlorpheniramine metabolism.
What to do
Monitor for increased drowsiness and anticholinergic effects, especially if istradefylline is used at the higher dose. Lower the chlorpheniramine dose if needed.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Chlorpheniramine
Other interactions of Istradefylline
Frequently asked questions
Can I take Chlorpheniramine with Istradefylline?
MediHelp rates the interaction as minor. Chlorpheniramine and Istradefylline have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. At higher doses istradefylline weakly inhibits CYP3A4 and may increase exposure to CYP3A4 substrates like chlorpheniramine. Sedation and anticholinergic effects may therefore be more pronounced.
How serious is the interaction between Chlorpheniramine and Istradefylline?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for increased drowsiness and anticholinergic effects, especially if istradefylline is used at the higher dose. Lower the chlorpheniramine dose if needed.
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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