Drug interactions
Clemastine + Diazepam
Severity: Moderate
Clemastine and Diazepam: 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
Clemastine is a sedating antihistamine, and with diazepam it can increase drowsiness and reduce psychomotor performance. The risk is greatest in older adults and when alcohol is also consumed.
What this interaction means in plain words
Clemastine and Diazepam 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.
Clemastine belongs to Respiratory; Diazepam belongs to Musculoskeletal.
Why it happens
Additive CNS depression from central H1 antagonism and GABA-A potentiation.
What to do
Counsel on avoiding driving and alcohol, and consider a non-sedating antihistamine. Monitor older patients for confusion and falls.
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 Diazepam
Other interactions of Clemastine
Frequently asked questions
Can I take Clemastine with Diazepam?
MediHelp rates the interaction as moderate. Clemastine and Diazepam 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. Clemastine is a sedating antihistamine, and with diazepam it can increase drowsiness and reduce psychomotor performance. The risk is greatest in older adults and when alcohol is also consumed.
How serious is the interaction between Clemastine and Diazepam?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Counsel on avoiding driving and alcohol, and consider a non-sedating antihistamine. Monitor older patients for confusion and falls.
What other medicines interact with Diazepam?
MediHelp also lists interactions of Diazepam with, for example, Calcium / magnesium / potassium / sodium oxybates, Alfentanil, Alprazolam. The full list is on the Diazepam page.
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