Drug interactions
Chlorpheniramine + Letermovir
Severity: Minor
Chlorpheniramine and Letermovir: 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
Letermovir is a moderate CYP3A inhibitor and may raise chlorpheniramine exposure. This could increase sedation and anticholinergic effects.
What this interaction means in plain words
Chlorpheniramine and Letermovir 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; Letermovir belongs to Anti Virals.
Why it happens
Inhibition of CYP3A4 by letermovir decreases chlorpheniramine metabolism.
What to do
Monitor for increased sedation and anticholinergic effects, and lower the chlorpheniramine dose if they occur.
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 Letermovir
- Ergotamine + Letermovir Contraindicated
- Letermovir + Pimozide Contraindicated
- Apalutamide + Letermovir Major
- Atorvastatin + Letermovir Major
- Carbamazepine + Letermovir Major
- Colchicine + Letermovir Major
Frequently asked questions
Can I take Chlorpheniramine with Letermovir?
MediHelp rates the interaction as minor. Chlorpheniramine and Letermovir have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Letermovir is a moderate CYP3A inhibitor and may raise chlorpheniramine exposure. This could increase sedation and anticholinergic effects.
How serious is the interaction between Chlorpheniramine and Letermovir?
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 sedation and anticholinergic effects, and lower the chlorpheniramine dose if they occur.
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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