The use of cocaine and other psychostimulants reflects a complex interaction between the pharmacology of the drug, the personality and expectations of the user, and the environmental context in which the drug is used. Polydrug use involving the concurrent use of several drugs with different pharmacologic effects is increasingly common. Sometimes one drug is used to enhance the effects of another, as with the combined use of cocaine and nicotine, or cocaine and heroin in methadone-maintained patients. Some forms of polydrug use, such as the combined use of IV heroin and cocaine, are especially dangerous and account for many hospital emergency room visits. Chronic cocaine and psychostimulant use may cause a number of adverse health consequences and may exacerbate preexisting disorders such as hypertension and cardiac disease. In addition, the combined use of two or more drugs may accentuate medical complications associated with use of one drug. Chronic drug use is often associated with immune system dysfunction and increased vulnerability to infections, including risk for HIV infection. The concurrent use of cocaine and opiates (“speedball”) is frequently associated with needle sharing by people using drugs intravenously. People who use IV drugs represent the largest single group of individuals with HIV infection in several major metropolitan areas in the United States as well as in many parts of Europe and Asia.
Stimulants and hallucinogens have been used to induce euphoria and alter consciousness for centuries. Cocaine and marijuana are two of the most commonly used drugs today. Synthetic variations of marijuana and a variety of hallucinogens have become popular recently, and new drugs are continually being developed. This chapter describes the subjective and adverse medical effects of cocaine, other psychostimulants including methamphetamine, 3,4-methylenedioxymethamphetamine (MDMA), and cathinones; as well as hallucinogens such as phencyclidine (PCP), D-lysergic acid diethylamide (LSD), salvia divinorum; and marijuana and the synthetic cannabinoids. Some options for medical management of severe adverse effects are also described.
PHARMACOKINETICS/DYNAMICS, NEUROBIOLOGY, AND EPIDEMIOLOGY
Cocaine is a powerful stimulant drug made from the cocoa plant. It has local anesthetic, vasoconstrictor, and stimulant properties. Cocaine is a Schedule II drug, which means that it has high potential for abuse but can be administered by a physician for legitimate medical uses, such as local anesthesia for some eye, ear, and throat surgeries.
Cocaine comes in a variety of forms, the most commonly used being the hydrochloride salt, sulfate, and a base. The salt is an acidic, water-soluble powder with a high melting point, used by snorting or sniffing intranasally or by dissolving it in water and injecting it intravenously. When used intranasally the bioavailability of cocaine is about 60 per percent. Cocaine sulfate (“paste”) has a melting point of almost 200°C, so it has limited use, but is sometimes smoked with tobacco. The base form can be freebase or crystallized as crack. Cocaine freebase ...