Heroin is an addictive opioid derived from the poppy plant and is closely related to morphine. Its effects are even more harmful than those of cocaine. Nevertheless, it is estimated that almost 4 million people in the United States have used heroin at least once, and that in 2012 more than 650,000 people used the drug at some time during the year. As sold on the street, it is cut (diluted) with an agent (often talc or quinine); thus, the size of the dose not only is variable but also usually is unknown to the buyer. Heroin, along with any contaminating substances, usually is self-administered intravenously or subcutaneously. Effects are varied and include euphoria, hallucinations, somnolence, and sedation. Heroin has a wide range of adverse physical effects that can be categorized etiologically according to (1) the pharmacologic action of the agent, (2) reactions to the cutting agents or contaminants, (3) hypersensitivity reactions to the drug or its adulterants, and (4) diseases contracted through the sharing of needles. Some of the most important adverse effects of heroin are the following:
Sudden death. Sudden death, usually related to overdose, is an ever-present risk, because drug purity generally is unknown and may range from 2% to 90%. The yearly incidence of sudden death among chronic users in the United States is estimated to be between 1% and 3%. Sudden death sometimes is due to a loss of tolerance for the drug, such as after a period of incarceration. The mechanisms of death include profound respiratory depression, arrhythmia and cardiac arrest, and pulmonary edema.
Pulmonary disease. Pulmonary complications include edema, septic embolism, lung abscess, opportunistic infections, and foreign body granulomas from talc and other adulterants. Although granulomas occur principally in the lung, they also are sometimes found in the spleen, liver, and lymph nodes that drain the upper extremities. Examination under polarized light often highlights trapped talc crystals, sometimes enclosed within foreign body giant cells.
Infections. Infectious complications are common. The sites most commonly affected are the skin and subcutaneous tissue, heart valves, liver, and lungs. In a series of addicted patients admitted to the hospital, more than 10% had endocarditis, which often takes a distinctive form involving right-sided heart valves, particularly the tricuspid. Most cases are caused by Staphylococcus aureus, but fungi and a multitude of other organisms have also been implicated. Viral hepatitis is the most common infection among addicts and is acquired by the sharing of dirty needles. In the United States, this practice has also led to a very high incidence of human immunodeficiency virus (HIV) infection in intravenous drug abusers.
Skin lesions. Cutaneous lesions probably are the most frequent telltale sign of heroin addiction. Acute changes include abscesses, cellulitis, and ulcerations resulting from subcutaneous injections. Scarring at injection sites, hyperpigmentation over commonly used veins, and thrombosed veins are the usual sequelae of repeated intravenous inoculations.
Renal problems. Kidney disease is a relatively common hazard. The two forms most frequently encountered are amyloidosis (generally secondary to skin infections) and focal glomerulosclerosis; both induce heavy proteinuria and the nephrotic syndrome.