Benzodiazepine (often colloquially referred to as benzos) is a pharmaceutical class of drugs used for its sedative effect. Benzodiazepines induces sleep, reduces anxiety, reduces convulsions and relaxes muscles. They are used for the treatment of anxiety, insomnia, agitation, seizures and muscle spasms. They can also be used to alleviate the effect of alcohol withdrawal and are often used to prepare a patient for either surgical or dental anesthesia. It was first synthesized in 1955 and was first marketed in 1960.