Many people take medications for allergy symptoms.
Some of these medications, particularly the older nonprescription antihistamines, can cause drowsiness. It is generally known that driving while drowsy can be unsafe. However, the influence of antihistamines on driving performance has not been studied in detail. The researchers wanted to determine exactly how much two common antihistamines affect driving performance. Forty experienced licensed drivers 25 to 44 years of age who had seasonal allergies.