Drug interactions
Chlorpheniramine + Clonazepam
Severity: Moderate
Chlorpheniramine and Clonazepam: 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
Chlorpheniramine is a sedating antihistamine that can add to clonazepam drowsiness and impair attention and coordination. Older patients are at higher risk of confusion and falls.
What this interaction means in plain words
Chlorpheniramine and Clonazepam 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; Clonazepam belongs to Central Nervous System.
Why it happens
Additive CNS depression from central H1 antagonism and GABA-A potentiation.
What to do
Prefer a non-sedating antihistamine when possible. Counsel patients to avoid driving and alcohol while taking both.
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 Clonazepam
- Calcium / magnesium / potassium / sodium oxybates + Clonazepam Contraindicated
- Clonazepam + Sodium oxybate Contraindicated
- Alfentanil + Clonazepam Major
- Alprazolam + Clonazepam Major
- Amobarbital + Clonazepam Major
- Belladonna and opium + Clonazepam Major
Other interactions of Chlorpheniramine
Frequently asked questions
Can I take Chlorpheniramine with Clonazepam?
MediHelp rates the interaction as moderate. Chlorpheniramine and Clonazepam 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 is a sedating antihistamine that can add to clonazepam drowsiness and impair attention and coordination. Older patients are at higher risk of confusion and falls.
How serious is the interaction between Chlorpheniramine and Clonazepam?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Prefer a non-sedating antihistamine when possible. Counsel patients to avoid driving and alcohol while taking both.
What other medicines interact with Clonazepam?
MediHelp also lists interactions of Clonazepam with, for example, Calcium / magnesium / potassium / sodium oxybates, Sodium oxybate, Alfentanil. The full list is on the Clonazepam page.
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