Drug interactions
Chlorpheniramine + Primidone
Severity: Moderate
Chlorpheniramine and Primidone: 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
Primidone is metabolized to phenobarbital and causes sedation. Chlorpheniramine can add to drowsiness and impair psychomotor performance.
What this interaction means in plain words
Chlorpheniramine and Primidone 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; Primidone belongs to Central Nervous System.
Why it happens
Additive CNS depression from barbiturate-mediated GABA-A potentiation and H1 antagonism.
What to do
Monitor for excessive sedation and advise against driving and alcohol. Consider 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 Primidone
- Lorlatinib + Primidone Contraindicated
- Lurasidone + Primidone Contraindicated
- Primidone + Ranolazine Contraindicated
- Primidone + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
- Primidone + Voriconazole Contraindicated
- Abiraterone + Primidone Major
Frequently asked questions
Can I take Chlorpheniramine with Primidone?
MediHelp rates the interaction as moderate. Chlorpheniramine and Primidone 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. Primidone is metabolized to phenobarbital and causes sedation. Chlorpheniramine can add to drowsiness and impair psychomotor performance.
How serious is the interaction between Chlorpheniramine and Primidone?
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 excessive sedation and advise against driving and alcohol. Consider 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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