Chlorpheniramine and Diazepam interaction

Chlorpheniramine and Diazepam: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.

Major

Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.

What the FDA labels say

From the Chlorpheniramine (Chlorphen-12) label · effective 2018-12-19

Major

…have a breathing problem such as emphysema or chronic bronchitis glaucoma trouble urinating due to an enlarged prostate gland Ask a doctor or pharmacist before use if you are taking sedatives or tranquilizers When using this product excitability may occur, especially in children drowsiness may occur avoid alcoholic beverages alchohol, sedatives and tranquilizers…

Warningsby drug classView label on DailyMed

From the Diazepam (Valium) label · effective 2026-08-11

Moderate

…be given to the pharmacology of the agents employed particularly with compounds that may potentiate or be potentiated by the action of Valium, such as phenothiazines, antipsychotics, anxiolytics/sedatives, hypnotics, anticonvulsants, narcotic analgesics, anesthetics, sedative antihistamines, narcotics, barbiturates, MAO inhibitors and other antidepressants.

Drug interactionsby drug classView label on DailyMed
Minor

Since Valium has a central nervous system depressant effect, patients should be advised against the simultaneous ingestion of alcohol and other CNS- depressant drugs during Valium therapy.

Warningsby drug classView label on DailyMed
Minor

Patients should be advised against the simultaneous ingestion of alcohol and other CNS-depressant drugs during Valium therapy.

Precautionsby drug classView label on DailyMed

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Not medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.