Cocaine is a powerful central nervous system stimulant that comes from the South American coca bush. The cocaine (cocaine hydrochloride) most commonly used in the U.S. is a white crystalline powder extracted from coca leaves. The cocaine bought on the street is a mixture of pure cocaine and other substances such as talc, flour, laxatives, sugar, local anesthetics and other stimulants or powders that are added to stretch the supply and increase the seller's profit.

Users buy powdered cocaine in grams (1/28 of an ounce) or in fractions of a gram called "quarters" or "eighths." Often, cocaine is snorted through the nose. Razor blades are used to crush any large rocks or particles of cocaine and to form "lines" that make snorting easier. Some users inject cocaine into a muscle or vein; others convert it into a smoke able form called freebase.

Freebase is street cocaine that is converted to a pure base by removing the hydrochloride salt and many of the "cutting" agents. The end product, freebase, is not water soluble -- the only way to get it into the system is to smoke it.

Crack is a light brown or beige pellet of ready-to-smoke freebase cocaine. It is formed when powdered cocaine is melted in a glass tube with water. When the liquid cools, it is mixed with baking soda and cold water and cut into small pieces, which then harden. Since it enters the system directly through the lungs, smokeable cocaine reaches the brain faster than when cocaine is snorted, and causes a more intense reaction.

Prior to 1980, cocaine abuse was a minor drug abuse problem. Its usage increased dramatically in the 1980s, and peaked in 1985 at 2.7 percent of the population, according to the National Household Survey. Household Survey data do not present the complete picture, as many subpopulations of hard-core addicts continue in their frequency of abuse, although the number of occasional cocaine abusers has declined dramatically.

The most dangerous form of smoke able cocaine is coca paste made by using gasoline or sulfuric acid to extract a smoke able paste. The paste is dried and smoked in a pipe or crushed into a cigarette.

Cocaine may be used with other drugs to produce a variety of effects. “Speedballing” is the combination of cocaine and heroin in a syringe for injection. “Spaceballing” is the sprinkling of liquid PCP (Phencyclidine) on crack cocaine before smoking. "Champagne" is the combination of cocaine and marijuana.

When cocaine is snorted, the effects begin within a few minutes, peak in 15 to 20 minutes and disappear after a few hours. Low doses produce a short period of euphoria and feelings of increased energy, alertness, self-esteem and sensory awareness. While artificially depleting the body's energy supply, cocaine reduces the perceived need for food and sleep and can cause impulsive behavior and mood changes.

Smoking freebase produces a two- to five-minute intense high. Because larger amounts get to the brain quickly, smoking also increases the risks of using the drug. Risks include confusion, anxiety, slurred speech and psychological problems.

Smoking crack produces an intense and rapid euphoria commonly known as a flash high. Cocaine molecules reach the brain in less than 10 seconds. The resulting three- to five-minute high is followed by an unpleasant crash. The user feels irritable and agitated, and has an intense craving for more cocaine caused by the high concentration of the drug in the bloodstream. The initial high is never reached again, and subsequent lows get lower. This cycle reinforces the craving.

Injecting cocaine produces an effect within 30 seconds that peaks in five minutes and lasts about a half hour. Users who inject run the risk of contracting hepatitis, AIDS, and other infections due to the sharing or use of contaminated needles.

Cocaine and crack constrict the heart's blood vessels, making it work harder and faster. In some users, this may trigger chest pain or a heart attack. Cocaine can interfere with the signals controlling the heart's pumping action, causing it to beat so irregularly it may stop. Cocaine, in all forms, has been associated with sudden heart attacks in people under 30, some of whom had used the drug for the first time.

Cocaine and crack can cause brain seizure, a disturbance in the brain's electrical signals, some of which regulate the heart and muscles controlling breathing. Studies show that over time, the brain appears to become more and more sensitive to cocaine. As a result, the threshold at which seizures occur is lowered. Repeated use of the drug without experiencing problems does not guarantee that seizures will not occur. The next dose -- used in the same amount and the same way -- can produce a seizure that may cause the heart to quit beating or the muscles that control breathing to stop working. Some users have suffered strokes after using cocaine.

Other effects of cocaine and crack use include:

• Suicidal tendencies

• Dramatic mood swings

• Chronic nose bleeds, runny nose or sore throat

• Loss of friends and former values

• Miscarriage/birth defects

•  Weight loss, resulting from a loss of appetite

• Chronic headaches

•  Respiratory ailments

• Addiction

• Death

The obsessive drug-seeking behavior of cocaine and crack users is due to the drug's overwhelming influence on the "reward center" in the brain, which is associated with an individual's drive for food, water and sex.

Cocaine use triggers the release of dopamine, a chemical that transmits feelings of pleasure and well-being, in the brain. The brain requires more and more dopamine to be released to satisfy its needs, which in turn requires greater amounts of cocaine to be used. An individual becomes more tolerant of the effects and has to use greater amounts to achieve the same high. Repeated compulsive use of cocaine may lead to highs that produce no pleasurable feelings.

Violent, erratic or paranoid behavior, called "cocaine psychosis” can accompany use of these drugs, but may appear more rapidly in crack smokers. Affected users become anxious, believe they have superhuman powers, or become suspicious and paranoid, to the point that they believe they are in danger and react in bizarre or violent ways. Hallucinations are also common. Users may hear or see things that do not exist, or experience "coke bugs" -- a sensation of imaginary insects crawling over the skin.

A cocaine high is often followed by a crash lasting 30 to 60 minutes or longer and leaving the user feeling tired and irritable. Cocaine use provides relief from these symptoms, creating the cycle of use. Generally, the higher a person gets on cocaine, the worse the effects of the crash. Whether or not an individual experiences a crash depends on the individual and the amount of cocaine used. Withdrawal following prolonged use of cocaine can cause irritability, nausea, agitation, sleep disorders, severe depression, muscle aches and an intense craving for the drug.

• Dilated pupils

• Dry mouth and nose, bad breath, frequent lip licking

• Excessive activity -- difficulty in sitting still

• Talkative but conversation lacks continuity

• Runny nose, cold or chronic sinus/nasal problems

• Sudden drop in grades or work performance

• Frequently in trouble or accident-prone

• Use or possession of paraphernalia

The long lasting craving for cocaine makes addiction hard to treat without assistance. The first step in treatment is detoxification, to rid the body of the drug. Detoxification is sometimes followed by medication, such as antidepressants, to control the craving and treat the depression that occurs after cocaine or crack is withdrawn. A treatment program can help the recovering user find other alternatives to curb the craving. Often this help is offered through a combination of individual, group and family counseling.