When injected, a super stimpak heals 75 hit points immediately, but the powerful nature of drugs used in the process will cause an adverse reaction from the organism, resulting in 9 points of damage after two minutes.
The super stimpak is a rare sight in the wasteland, usually only available from high tech settlements, such as Vault City or San Francisco.
Super stimpaks also have a nefarious purpose. They can be used to assassinate friendly non-player characters in populated areas; no one would suspect you of killing the person with stimpaks, because they heal people. Having the Awareness perk helps, as you can see how much health the target has. Simply divide his or her maximum health by 9 then round up. The number you reach is how many super stimpaks you should use to kill your victim. Stick the stimpaks in one of your weapon slots and use the applicable number of stimpaks on the victim. After waiting 2 minutes, they should die from the latent damage (9 points per pak').