The body naturally releases opioids (endorphins) that bind with opioid receptors in the brain during certain activities. When released, these natural feel-good chemicals deliver a rush of pleasure and minimize the experience of pain throughout the body. Heroin and opioid prescriptions bind with the brain’s natural opioid receptors to block pain and deliver an experience of euphoria.
With continued use, a person’s natural ability to release endorphins diminishes, and he or she may begin to crave the experience of the endorphin imposter. Users also develop a tolerance to opioid dosage and need to take ever increasing amounts to experience the same “high.”
The good feeling resulting from the use of an outside opioid is not risk free. The same mechanisms that dull the sensation of pain also depress respiration. If someone takes too much, they can begin to lose oxygen and suffocate. Without an antidote such as naloxone to counteract the effect, a user may die of an overdose.