Some
antihistamines cause drowsiness, which can be increased by
alcohol. The detrimental effects of
alcohol on driving skills are considerably increased by the use of the older more sedative
antihistamines (e.g. diphenhydramine, hydroxyzine) and appear to be minimal or absent with the newer non-sedating
antihistamines (e.g.
cetirizine, loratadine). Note that some of the more sedative
antihistamines are common ingredients of cough, cold and
influenza remedies.
The degree of impairment will depend on the individual patient. However, warn all patients taking sedating
antihistamines of the potential effects, and counsel against driving or undertaking other skilled tasks.