[Sedating antihistamines - risk of severe intoxication]

Overdoses with the sedating antihistamines alimemazine, hydroxyzine, promethazine and propiomazine have received attention in recent years in Sweden. The Poisons Information Center has noted an increase in calls regarding intoxications, and the National Board of Forensic Medicine has concluded that these substances have directly contributed to a large number of poisoning deaths. When prescribing alimemazine, hydroxyzine, promethazine and propiomazine, their pharmacological properties, such as antihistaminergic and anticholinergic effects, and their anti-arrhythmic potential must be considered. Furthermore, it is important to also consider the risks of severe intoxication in case of overdose. The lowest possible amount should be prescribed. Special attention is required when prescribing alimemazine oral solution.