Drugs have been widely associated with the development of delirium in the elderly and represent the most common reversible cause of this condition. This is of importance since successful treatment depends on identifying the reversible contributing factors. Medications with anticholinergic properties, tranquilizers, analgesics and narcotics are common causes of drug-induced delirium. This article provides practical approach to prevent and recognise this condition, reviews the underlying neurotransmitter imbalances and reconsiders age-related changes of pharmacological effects, which may contribute to the development of delirium.