Methohexital
From Memory Alpha, the free Star Trek reference.
Methohexital is a sedative barbiturate substance which is primarily used in hospitals and other medical facilities. It is often used in tandem with anesthesia to induce a deep "twilight"-like sleep state.
In 2004, Loomis stole some Methohexital from a blood bank at which he worked to sedate his victims in order to take blood samples from them to accommodate the Xindi-Reptilians' request for all Humans' blood types. (ENT: "Carpenter Street")
