The person may be feeling itchy all over and scratching. Physical effects may include slowed breathing, constricted pupils, and oftentimes nausea and vomit. For example, heroin does not produce a drastic change in blood pressure in healthy individuals. Most negative effects are related to the life style of the addict. Users lose weight because they spend time and energy chasing down the drug.
Injection can also cause permanent damage to blood vessels.
Because of the effect of heroin in suppressed breathing, long term addicts show loss of blood oxygen. Heroin is most often injected, smoked, or sniffed. Heroin can be sniffed because it is absorbed across the mucous lining of the nose. Like other opiates, heroin forms a vapor if heated , so it can be absorbed into the body if it is smoked. Heroin can also be absorbed through the stomach.