One brand of autoinjector for epinephrine is an Epi-pen, which is often prescribed to persons who have survived anaphylaxis.
In the United States Army, autoinjectors loaded with atropine are used for first aid against chemical weapons, particularly nerve agents. In the Gulf War, accidental and unnecessary use of atropine autoinjectors proved to be a major medical problem.
Combat lifesavers and some other soldiers are issued autoinjectors loaded with morphine, or Syrettes, to administer to severely injured persons for pain control. Special operations soldiers have been known to inject multiple Syrettes immediately prior to capture in order to avoid immediate interrogation at the severe risk of an overdose. Why? Is this intended as a mechanism of suicide, and what is gained by delaying interrogation for a few hours/days?