If someone murders someone and they are under the influence of a substance that caused them to black out and they were unaware of there actions what will happen to them with sentencing?

They could still be tried for manslaughter, which is homicide without maliciousness, usually do to negligence.

For example, a babysitter could be tried for manslaughter if the toddler they were babysitting got ahold of a plastic bag and suffocated to death. In both instances of consuming the substance and leaving plastic bags out within reach of the toddler, someone died due to the negligence of another.