Immediate effects of heroin on the body include a surge of euphoria, a warm feeling on the skin, a feeling of heaviness in the extremities and nausea, according to the National Institute on Drug Abuse. Users may afterwards experience drowsiness and clouded mental function for several hours. Long-term effects include changes in brain structure, addiction and physical dependence.
Heroin converts to morphine once it enters the brain, binding to opioid receptors to produce a feeling of pleasure, notes the National Institute on Drug Abuse. Users may also experience dry mouth, severe itching and vomiting. Once the initial effects pass, breathing and heartbeat slow considerably, potentially leading to coma, permanent brain damage and even death.
Long-term use can lead to brain structure changes that can create long-term hormonal and neuronal imbalances, states the National Institute on Drug Abuse. Studies also show that long-term heroin use deteriorates white matter in the brain, affecting the ability to regulate behavior and make decisions. Users may become physically dependent on heroin, requiring greater amounts or a greater frequency of use to achieve desired effects. The substance is also highly addictive despite the method of administration, often leading to uncontrolled drug-seeking. Using and finding heroin may become the user's sole purpose in life.