I'm old, so my first addition to the key ring was a pill capsule for some aspirin for heart attack or stroke,
"Don't take aspirin if you think you're having a stroke, because not all strokes are caused by blood clots; some are caused by ruptured blood vessels. Taking aspirin could make a bleeding stroke more severe."
http://www.mayoclinic.com/health/daily-aspirin-therapy/HB00073/NSECTIONGROUP=2