Heroin effects an user’s life in many different ways. These effects are felt both in the short term as well as long term. Almost immediately after heroin is used (injected, snorted, or smoked) its effects are felt on the body’s central nervous system. Heroin effects take place rapidly after the user ingests the drug. Quickly after the user injects or snorts the drug, it crosses the blood-brain barrier. Once it enters the user’s brain, heroin is converted into morphine and binds itself to the opioids receptors located there. Heroin is one of the most addictive drugs because of how quickly it enters the user’s brain and begins to produce its effects.

Those who have taken the drug report a surge of pleasurable sensations shortly after ingesting heroin, known as a “rush.” How intense this rush is depends on how much heroin is taken and how quickly it enters their brain. The user will also feel a warm flushing of their skin, a dry mouth, and the feeling of having “heavy” extremities. After this initial rush, they will begin to “nod” in and out of consciousness. Their mental abilities will be diminished and their breathing rate will slow. This may be accompanied by nausea, vomiting, and severe itching.

The most dangerous of the long term heroin effects is addiction. When someone becomes addicted to heroin, their body physically needs the drug to function and prevent withdrawal from setting in. Addiction to heroin or any other drug is characterized by compulsive drug seeking and use. It is important to note that users who inject heroin may have additional long term complications including exposure to the human immunodeficiency virus (HIV), Hepatitis B and C, and other blood-borne viruses. Approximately 70 to 80 percent of new Hepatitis C infections in the United States each year are the result of injection drug use.

As with abusers of any addictive drug, heroin abusers gradually spend more and more time and energy obtaining and using the drug. Users develop a tolerance to heroin over time and find that they need more and more of the drug to maintain a feeling of “normality.” After a certain point, most addicts no longer experience heroin’s initial rush and strictly take the drug to get through the day. Sometimes addicted individuals will endure withdrawal symptoms in an attempt to reduce their tolerance for the drug so they can again experience the rush.

Heroin effects include experiencing withdrawal symptoms if the drug is not consumed. Symptoms of withdrawal include restlessness, muscle and bone pain, insomnia, diarrhea, vomiting, cold flashes with goose bumps ("cold turkey"), and uncontrolled leg movements. Major withdrawal symptoms peak between 24 and 48 hours after the last dose of heroin and subside after about a week.

Some people have shown persistent withdrawal signs for many months. Heroin withdrawal is never fatal to otherwise healthy adults. However, it can cause death to the fetus of a pregnant addict. Physical dependence and the emergence of withdrawal symptoms were once believed to be the key features of heroin addiction. We now know this may not be the case entirely, since craving and relapse can occur weeks and months after withdrawal symptoms are long gone.

Those who abuse heroin for an extended period of time may experience these long term heroin effects:

• Abscesses
• Infection of the heart lining and valves
• Kidney disease
• Liver disease
• Pneumonia
• Pulmonary complications
• Scarred or collapsed veins
• Tuberculosis