Sedatives are central nervous system (CNS) depressants, meaning that they depress or slow down brain activity. Sedatives are most commonly used as medications to treat anxiety, insomnia or other sleep-related disorders. Other medical uses include inducing sedation for surgical and medical procedures, treatment of alcohol withdrawal, seizures and migraines, and as muscle relaxants. There are three main classes of sedatives: benzodiazepines, non-benzodiazepine sleep medications and barbiturates. Examples of drugs in each of these three classes are listed in Table 1 with their corresponding generic, trade and street names. Sedatives are often referred to interchangeably as tranquillizers or hypnotics.