A number of drugs of abuse are administered by injection to achieve a more rapid or potent effect or both. Drugs are typically injected IV but may be injected subcutaneously, IM, or even sublingually. Users typically access peripheral veins, but when these have sclerosed due to chronic use, some learn to inject into large central veins (eg, internal jugular, femoral, axillary).
Complications of Injection Drug Use
People who inject illicit drugs risk not only the adverse pharmacodynamic effects of the drugs but also complications related to contaminants, adulterants, and infectious agents that may be injected with the drug.
Adulterants
Street drugs such as heroin and are often “cut” with various adulterants (eg, amphetamineslysergic acid diethylamide [LSD]
Infectious agents
Needle sharing and use of nonsterile techniques can lead to many infectious complications. Injection site complications include cutaneous abscesses, cellulitis, lymphangitis, lymphadenitis, and thrombophlebitis. Distant focal infectious complications due to septic emboli and bacteremia include bacterial endocarditis and abscesses in various organs and sites. Septic lung emboli and osteomyelitis (particularly lumbar vertebral) are particularly common. Patients may develop a spinal epidural abscess. Infectious spondylitis and sacroiliitis may occur.
Systemic infectious diseases are primarily hepatitis B and C and HIV infection. IV drug users are at high risk of pneumonia, resulting from aspiration or hematogenous spread of bacteria. Other infections that are not directly caused by drug injection but are common among IV drug users include tuberculosis, syphilis, and other sexually transmitted infections. Even botulism and tetanus can result from IV drug abuse.
Diagnosis of Injection Drug Use
History, physical examination, or both
Some patients readily admit to injection drug use, but for others, a thorough physical examination is needed to detect evidence of injection.
Chronic IV drug use can be confirmed by observing track marks due to repeated injections into subcutaneous veins. Track marks are a linear area of tiny, dark punctate lesions (needle punctures) surrounded by an area of darkened or discolored skin due to chronic inflammation. Track marks are often found in easily accessible sites (eg, antecubital fossa, forearms), but some drug users try to hide evidence of their injections by choosing less obvious sites (eg, axillae).
Subcutaneous injection (skin popping) can cause characteristic circular scars or ulcers; there may be signs of previous abscesses. People with substance use disorders may deny stigmata of drug use by attributing track marks to frequent blood donations, bug bites, or previous trauma.
Treatment of Injection Drug Use
Treatment and prevention of infectious complications
Substance abuse rehabilitation
Drug users, especially those with a history of injection drug use, should be thoroughly evaluated for viral hepatitis, HIV infection, and the wide range of other infectious diseases common among these patients (eg, tuberculosis, syphilis, other sexually transmitted infections). Also, vaccination to prevent hepatitis, influenza, pneumococcal infections, tetanus infection, and other infections should be offered to all appropriate patients.
The AIDS epidemic triggered a harm-reduction movement, which aims to reduce the harm of drug use without necessarily requiring cessation. For example, providing clean needles and syringes for users who cannot stop injecting drugs reduces the spread of HIV and hepatitis.
Treatment of infectious complications is the same as that for similar infections resulting from other conditions; it includes use of antibiotics for bacterial infections and incision and drainage of abscesses. Treatment may be complicated by difficulty obtaining venous access and by poor adherence to treatment regimens.
