Barbiturates are a class of around 12 compounds derived from barbituric acid. They are central nervous system depressants that can be used as sedatives, hypnotics, anaesthetics or anti-epileptic drugs. Barbiturates can be divided into three main groups according to their duration of action. The ultrashort-acting barbiturates are used clinically as anaesthetics whilst the long-acting barbiturates have anti-convulsing properties. Short-acting compounds can be used as hypnotics and favoured by drug abusers due to their ability to reduce tension and produce a feeling of tranquillity. An overdose of barbiturates can lead to a dramatic fall in blood pressure and body temperature, depressed respiration or coma.
