I am writing a story and in a later point of the story, the main character who is an agent of a secret government agency 'persuades' a high ranking official of some evil syndicate that I have not yet named. He persuades the official by telling him that if he left the syndicate and gave his aid to help and destroy it, then he would have all past afflictions and illegal counts dropped. The agent slips the official a drug that makes him unaware of his actions and makes it impossible for him to recall any recent events. It can be administered in almost any way except syringe. It can be any kind of drug and it was not issued by his agency, he obtained it from his friend who does some chemical consulting for various companies. Anyway, he slips the official the drug and he completely forgets that he helped the agent bring the syndicate down and his promise to drop all charges against him and is then sentenced to life in a maximum security prison. Is there a drug that can give a person temporary amnesia without rendering them unconsious that lasts about a few hours and makes them sort of unaware of their actions? I am trying to make it seem as realistic as possible, so I need a real drug and quantity that will give the desired effect.