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Research Report Series

Cocaine Abuse and Addiction

How is cocaine used?

The principal routes of cocaine administration are oral, intranasal, intravenous, and inhalation. The slang terms for these routes are, respectively, "chewing," "snorting," "mainlining," "injecting," and "smoking" (including freebase and crack cocaine). Snorting is the process of inhaling cocaine powder through the nostrils, where it is absorbed into the bloodstream through the nasal tissues. Injecting releases the drug directly into the bloodstream, and heightens the intensity of its effects. Smoking involves the inhalation of cocaine vapor or smoke into the lungs, where absorption into the bloodstream is as rapid as by injection. The drug can also be rubbed onto mucous tissues. Some users combine cocaine powder or crack with heroin in a "speedball."

Cocaine use ranges from occasional use to repeated or compulsive use, with a variety of patterns between these extremes. There is no safe way to use cocaine. Any route of administration can lead to absorption of toxic amounts of cocaine, leading to acute cardiovascular or cerebrovascular emergencies that could result in sudden death. Repeated cocaine use by any route of administration can produce addiction and other adverse health consequences.

How does cocaine produce its effects?

A great amount of research has been devoted to understanding the way cocaine produces its pleasurable effects, and the reasons it is so addictive. One mechanism is through its effects on structures deep in the brain. Scientists have discovered regions within the brain that, when stimulated, produce feelings of pleasure. One neural system that appears to be most affected by cocaine originates in a region, located deep within the brain, called the ventral tegmental area (VTA). Nerve cells originating in the VTA extend to the region of the brain known as the nucleus accumbens, one of the brain's key pleasure centers. In studies using animals, for example, all types of pleasurable stimuli, such as food, water, sex, and many drugs of abuse, cause increased activity in the nucleus accumbens.

Researchers have discovered that, when a pleasurable event is occurring, it is accompanied by a large increase in the amounts of dopamine released in the nucleus accumbens by neurons originating in the VTA. In the normal communication process, dopamine is released by a neuron into the synapse (the small gap between two neurons), where it binds with specialized proteins (called dopamine receptors) on the neighboring neuron, thereby sending a signal to that neuron. Drugs of abuse are able to interfere with this normal communication process. For example, scientists have discovered that cocaine blocks the removal of dopamine from the synapse, resulting in an accumulation of dopamine. This buildup of dopamine causes continuous stimulation of receiving neurons, probably resulting in the euphoria commonly reported by cocaine abusers.

As cocaine abuse continues, tolerance often develops. This means that higher doses and more frequent use of cocaine are required for the brain to register the same level of pleasure experienced during initial use. Recent studies have shown that, during periods of abstinence from cocaine use, the memory of the euphoria associated with cocaine use, or mere exposure to cues associated with drug use, can trigger tremendous craving and relapse to drug use, even after long periods of abstinence.

What are the short-term effects of cocaine use?

Cocaine's effects appear almost immediately after a single dose, and disappear within a few minutes or hours. Taken in small amounts (up to 100 mg), cocaine usually makes the user feel euphoric, energetic, talkative, and mentally alert, especially to the sensations of sight, sound, and touch. It can also temporarily decrease the need for food and sleep. Some users find that the drug helps them to perform simple physical and intellectual tasks more quickly, while others can experience the opposite effect.

The duration of cocaine's immediate euphoric effects depends upon the route of administration. The faster the absorption, the more intense the high. Also, the faster the absorption, the shorter the duration of action. The high from snorting is relatively slow in onset, and may last 15 to 30 minutes, while that from smoking may last 5 to 10 minutes.

The short-term physiological effects of cocaine include constricted blood vessels; dilated pupils; and increased temperature, heart rate, and blood pressure. Large amounts (several hundred milligrams or more) intensify the user's high, but may also lead to bizarre, erratic, and violent behavior. These users may experience tremors, vertigo, muscle twitches, paranoia, or, with repeated doses, a toxic reaction closely resembling amphetamine poisoning. Some users of cocaine report feelings of restlessness, irritability, and anxiety. In rare instances, sudden death can occur on the first use of cocaine or unexpectedly thereafter. Cocaine-related deaths are often a result of cardiac arrest or seizures followed by respiratory arrest.

What are the long-term
effects of cocaine use?

An appreciable tolerance to cocaine's high may develop, with many addicts reporting that they seek but fail to achieve as much pleasure as they did from their first experience. Some users will frequently increase their doses to intensify and prolong the euphoric effects. While tolerance to the high can occur, users can also become more sensitive (sensitization) to cocaine's anesthetic and convulsant effects, without incre
g the dose taken. This increased sensitivity may explain some deaths occurring after apparently low doses of cocaine.

Use of cocaine in a binge, during which the drug is taken repeatedly and at increasingly high doses, leads to a state of increasing irritability, restlessness, and paranoia. This may result in a full-blown paranoid psychosis, in which the individual loses touch with reality and experiences auditory hallucinations.

What are the medical complications of cocaine abuse?

Cocaine use has been linked to many types of heart disease. Cocaine has been found to trigger chaotic heart rhythms, called ventricular fibrillation; accelerate heartbeat and breathing; and increase blood pressure and body temperature. Physical symptoms may include chest pain, nausea, blurred vision, fever, muscle spasms, convulsions and coma.

Different routes of cocaine administration can produce different adverse effects. Regularly snorting cocaine, for example, can lead to loss of sense of smell, nosebleeds, problems with swallowing, hoarseness, and an overall irritation of the nasal septum, which can lead to a chronically inflamed, runny nose. Ingested cocaine can cause severe bowel gangrene, due to reduced blood flow. And, persons who inject cocaine have puncture marks and "tracks," most commonly in their forearms. Intravenous cocaine users may also experience an allergic reaction, either to the drug, or to some additive in street cocaine, which can result, in severe cases, in death. Because cocaine has a tendency to decrease food intake, many chronic cocaine users lose their appetites and can experience significant weight loss and malnourishment.

National Institute on Drug Abuse
Research Report Series

Cocaine Abuse and Addiction

Are cocaine abusers at risk
for contracting HIV/AIDS
and hepatitis B and C?

Yes. Cocaine abusers, especially those who inject, are at increased risk for contracting such infectious diseases as human immunodeficiency virus (HIV/AIDS) and hepatitis. In fact, use and abuse of illicit drugs, including crack cocaine, have become the leading risk factors for new cases of HIV. Drug abuse-related spread of HIV can result from direct transmission of the virus through the sharing of contaminated needles and paraphernalia between injecting drug users. It can also result from indirect transmission, such as an HIV-infected mother transmitting the virus perinatally to her child. This is particularly alarming, given that more than 60 percent of new AIDS cases are women. Research has also shown that drug use can interfere with judgement about risk-taking behavior, and can potentially lead to reduced precautions about having sex, the sharing of needles and injection paraphernalia, and the trading of sex for drugs, by both men and women.

Additionally, hepatitis C is spreading rapidly among injection drug users; current estimates indicate infection rates of 65 to 90 percent in this population. At present, there is no vaccine for the hepatitis C virus, and the only treatment is expensive, often unsuccessful, and may have serious side effects.

What is the effect of
maternal cocaine use?

The full extent of the effects of prenatal drug exposure on a child is not completely known, but many scientific studies have documented that babies born to mothers who abuse cocaine during pregnancy are often prematurely delivered, have low birth weights and smaller head circumferences, and are often shorter in length.

Estimating the full extent of the consequences of maternal drug abuse is difficult, and determining the specific hazard of a particular drug to the unborn child is even more problematic, given that, typically, more than one substance is abused. Such factors as the amount and number of all drugs abused; inadequate prenatal care; abuse and neglect of the children, due to the mother's lifestyle; socio-economic status; poor maternal nutrition; other health problems; and exposure to sexually transmitted diseases, are just some examples of the difficulty in determining the direct impact of perinatal cocaine use, for example, on maternal and fetal outcome.

Many may recall that "crack babies," or babies born to mothers who used cocaine while pregnant, were written off by many a decade ago as a lost generation. They were predicted to suffer from severe, irreversible damage, including reduced intelligence and social skills. It was later found that this was a gross exaggeration. Most crack-exposed babies appear to recover quite well. However, the fact that most of these children appear normal should not be over-interpreted as a positive sign. Using sophisticated technologies, scientists are now finding that exposure to cocaine during fetal development may lead to subtle, but significant, deficits later, especially with behaviors that are crucial to success in the classroom, such as blocking out distractions and concentrating for long periods of time.

What treatments are effective
for cocaine abusers?

There has been an enormous increase in the number of people seeking treatment for cocaine addiction during the 1980s and 1990s. Treatment providers in most areas of the country, except in the West and Southwest, report that cocaine is the most commonly cited drug of abuse among their clients. The majority of individuals seeking treatment smoke crack, and are likely to be poly-drug users, or users of more than one substance. The widespread abuse of cocaine has stimulated extensive efforts to develop treatment programs for this type of drug abuse. Cocaine abuse and addiction is a complex problem involving biological changes in the brain as well as a myriad of social, familial, and environmental factors. Therefore, treatment of cocaine addiction is complex, and must address a variety of problems. Like any good treatment plan, cocaine treatment strategies need to assess the psychobiological, social, and pharmacological aspects of the patient's drug abuse.

 Pharmacological Approaches

There are no medications currently available to treat cocaine addiction specifically. Consequently, NIDA is aggressively pursuing the identification and testing of new cocaine treatment medications. Several newly emerging compounds are being investigated to assess their safety and efficacy in treating cocaine addiction. For example, one of the most promising anti-cocaine drug medications to date, selegeline, is being taken into multi-site phase III clinical trials in 1999. These trials will evaluate two innovative routes of selegeline administration: a transdermal patch and a time-released pill, to determine which is most beneficial. Disulfiram, a medication that has been used to treat alcoholism, has also been shown, in clinical studies, to be effective in reducing cocaine abuse. Because of mood changes experienced during the early stages of cocaine abstinence, antidepressant drugs have been shown to be of some benefit. In addition to the problems of treating addiction, cocaine overdose results in many deaths every year, and medical treatments are being developed to deal with the acute emergencies resulting from excessive cocaine abuse.

Behavioral Interventions

Many behavioral treatments have been found to be effective for cocaine addiction, including both residential and outpatient approaches. Indeed, behavioral therapies are often the only available, effective treatment approaches to many drug problems, including cocaine addiction, for which there is, as yet, no viable medication. However, integration of both types of treatments is ultimately the most effective approach for treating addiction. It is important to match the best treatment regimen to the needs of the patient. This may include adding to or removing from an individual's treatment regimen a number of different components or elements. For example, if an individual is prone to relapses, a relapse component should be added to the program. A behavioral therapy component that is showing positive results in many cocaine-addicted populations, is contingency management. Contingency management uses a voucher-based system to give positive rewards for staying in treatment and remaining cocaine free. Based on drug-free urine tests, the patients earn points, which can be exchanged for items that encourage healthy living, such as joining a gym, or going to a movie and dinner. Cognitive-behavioral therapy is another approach. Cognitive-behavioral coping skills treatment, for example, is a short-term, focused approach to helping cocaine-addicted individuals become abstinent from cocaine and other substances. The underlying assumption is that learning processes play an important role in the development and continuation of cocaine abuse and dependence. The same learning processes can be employed to help individuals reduce drug use. This approach attempts to help patients to recognize, avoid, and cope; i.e., recognize the situations in which they are most likely to use cocaine, avoid these situations when appropriate, and cope more effectively with a range of problems and problematic behaviors associated with drug abuse. This therapy is also noteworthy because of its compatibility with a range of other treatments patients may receive, such as pharmacotherapy.