Opiates (such as heroin, morphine and Demerol) are sedatives known for being very strong pain relievers. In high doses, opiates decrease a person's ability to breathe. When someone overdoses on heroin or any of the prescription opiates, their speech becomes slurred, their reaction time decreases, their gait (walking) becomes unstable, and in the worst cases, their breathing gets shallow and slow. Opiates also cause constriction of the pupils (meaning the black circle in the middle of the eye gets very small).
Paramedics regularly respond to heroin overdoses where the victim is unconscious, won't respond to any shaking or shouting, isn't breathing and has "pinpoint pupils." In most cases, the victim still has a pulse. Indeed, opiate overdoses usually survive for several minutes without breathing (read Why Mouth to Mouth is Not Needed in CPR for an explanation on how this works).
Paramedics carry a medication called naloxone that is the perfect antidote for opiate overdoses. Naloxone is an opiate antagonist, which means it essentially blocks opiates from affecting the brain and actually kicks out the opiates that are already there. When we give naloxone to a victim of opiate overdose, they usually start breathing and wake right up. It's amazing to anyone who sees it for the first time.
If you have a friend or family member taking any type of opiate medications for pain, make sure they follow their prescription and talk to the doctor before increasing. This includes taking extra opiates when wearing pain patches. If a family member becomes unconscious and you cannot wake him or her, call 911.