Second generation antihistamines for treating hayfever often claim that they are 'non drowsy'. However, GP reports of adverse events associated with such drugs show that even non sedative antihistamines can produce drowsiness.
Some drugs are more often implicated than others, say researchers at the Drug Safety Research Unit at the University of Southampton. For example, those formulas which use cetirizine or acrivastine were three times more likely to produce drowsiness and sedation than those with loratadine or fexofenadine.
The study found no differences between drugs in terms of the number of accidents and injuries, falls and fractures which patients experienced while taking them. Nevertheless, the findings have clear implications for people in certain types of jobs where safety is critical, such as airline pilots or those operating heavy machinery (BMJ, 2000; 320:1184-7).