According to the National Institute on Drug Abuse Web site, heroin is made from morphine, a naturally occurring substance extracted from the seed pod of the Asian opium poppy plant, and appears as a white or brown powder or as black tar heroin.
After the drug's introduction to the body, it enters the brain, where it is converted to morphine, according to the Web site, and binds to receptors known as opioid receptors.
Following an intravenous injection of heroin, a surge of euphoria is felt by users, accompanied by dry mouth, a warm flushing of the skin and heaviness of the extremities.
The user goes into an alternately wakeful and drowsy state after the initial euphoria, and mental functioning becomes clouded, according to the Web site.
With regular heroin use, tolerance develops, and more heroin must be used to achieve the same intensity of effects.
According to the Web site, adverse effects from heroin include fatal overdose, spontaneous abortion and in users who inject the drug, infectious diseases, including HIV/AIDS and hepatitis.
Chronic users may develop collapsed veins, infection of the heart lining and valves, abscesses, and liver or kidney disease, and pulmonary complications also may develop.
Because street heroin often contains toxic contaminants or additives, clogged blood vessels leading to the lungs, liver, kidneys or brain can occur, causing permanent damage to vital organs, the Web site states.
Heroin withdrawal symptoms can begin as early as a few hours after the last drug administration and usually include restlessness, muscle and bone pain, insomnia, diarrhea and vomiting, cold flashes and kicking movements, according to the Web site.
Methadone, a medication commonly used in the detoxification process, helps users withdraw from the drug safely and is a synthetic opiate medication.
According to the Web site, methadone binds to the same receptors as heroin and reduces the desire for other opioid drugs while preventing withdrawal symptoms.
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