Premedication

Abstract

Administration of medications in advance of induction of anaesthesia, ‘premedication’, has a long history. With the earliest inhalational agents, ether and chloroform, induction was characterized by a prolonged period of involuntary movements, excessive salivation and feelings of severe anxiety. It became common practice, therefore, to premedicate patients with agents such as scopalamine (an early anticholinergic) to reduce secretions, and morphine, to reduce irritability and anaesthetic requirements. In the 1950s came intravenous induction agents and halogenated inhalation agents, and a smoother and more predictable induction and early maintenance phase, with much reduced salivation. The practice of premedication lingered however, although its main purpose was now simply to alleviate patient anxiety. The invention of benzodiazepines in the late 1950s was nicely timed to find for them a niche as favoured anxiolytic premedication. This persisted for many years. In modern anaesthesia practice, sedative/anxiolytic premedication is much less commonly used than heretofore. The pre-assessment consultation with the anaesthetist has largely replaced routine premedication for the purpose of alleviating anxiety, as several studies show that this can be quite effective in achieving a calm patient. The term premedication has lately taken on a broader meaning. It is now understood to include considerations regarding which of the patient's long-term medications should be withheld or continued in advance of their operation, and the introduction of medications with the aim of optimizing medical conditions or to improve certain peri-operative outcomes.

In this article we will first discuss premedication for the purposes of sedation/anxiolysis. We will then systematically examine some of the medications that are commonly the focus of preoperative decisions in the surgical patient. The list of medications discussed is by no means exhaustive. Finally, we will look at premedication in special patient populations.