Drug interactions
Chlorpheniramine + Lonafarnib
Severity: Moderate
Chlorpheniramine and Lonafarnib: 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
Lonafarnib inhibits CYP3A and may raise chlorpheniramine concentrations, increasing sedation and anticholinergic effects. The clinical impact is predicted rather than well documented.
What this interaction means in plain words
Chlorpheniramine and Lonafarnib 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; Lonafarnib belongs to Miscellaneous.
Why it happens
CYP3A inhibition by lonafarnib reduces chlorpheniramine metabolism.
What to do
Monitor for excess sedation and anticholinergic effects and reduce the chlorpheniramine dose, or choose a non-sedating antihistamine.
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 Lonafarnib
- Alfuzosin + Lonafarnib Contraindicated
- Amobarbital + Lonafarnib Contraindicated
- Apalutamide + Lonafarnib Contraindicated
- Bosentan + Lonafarnib Contraindicated
- Carbamazepine + Lonafarnib Contraindicated
- Clarithromycin + Lonafarnib Contraindicated
Frequently asked questions
Can I take Chlorpheniramine with Lonafarnib?
MediHelp rates the interaction as moderate. Chlorpheniramine and Lonafarnib 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. Lonafarnib inhibits CYP3A and may raise chlorpheniramine concentrations, increasing sedation and anticholinergic effects. The clinical impact is predicted rather than well documented.
How serious is the interaction between Chlorpheniramine and Lonafarnib?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for excess sedation and anticholinergic effects and reduce the chlorpheniramine dose, or choose a non-sedating antihistamine.
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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