Ativan (lorazepam) belongs to a class of medications called benzodiazepines. It is thought that benzodiazepines work by enhancing the activity of certain neurotransmitters in the brain.Ativan is used in adults and children at least 12 years old to treat anxiety disorders.Ativan is also used to treat insomnia caused by anxiety or temporary situational stress.Ativan is sometimes used to treat nausea and vomiting from cancer treatment and to control agitation caused by alcohol withdrawal.