Neural paralyzer
A neural paralyzer was a central nervous system depressant, standard in Starfleet medkits in the 23rd century. Used in surgery as a pre-anesthetic, it acted within five to ten minutes and lasted for fifteen to twenty minutes to depress cardiac and respiratory functions, incidentally making the subject nearly appear dead. 

In 2267, Doctor Leonard McCoy injected James T. Kirk with a neural paralyzer to simulate Kirk's death so that Spock could complete the koon-ut-kal-if-fee without actually killing Kirk. ()
Drugs