MethAmp

MethAmp is the short name for a methamphetamine-based stimulant that reduces fatigue and hunger, while increasing alertness and energy. While not as risky as it's 21st Century counterpart, this drug still has the potential to cause users to behave erratically, when applied in large doses. It can occasionally reduce accuracy or cause nervous muscular tics or personality disorders, when used in excessive amounts, but on the whole, it is a positive drug that does more good than harm. Again, it is not good to use this for extended amounts of time, as it could cause damage. 
It is often used by soldiers or marines who are expecting to operate for long periods of time without rest or food, requiring them to operate longer than usually possible.