|Cocaine - A Brief Overview|
|A History of the Study of Cocaine in Hair|
|The Controversy of Hair Testing|
|General Procedures of Hair Testing|
|Detailed Procedure to Extract Compounds|
|A Few Chemical Structures|
|>>>Go to Lab|
Cocaine - A Brief Overview
Cocaine is the most potent natural stimulant available to man. It is found in the leaves of the erythroxylon coca plant in the Andean highlands, and has been used for centuries as a soothing and energizing tea by natives of Peru and Bolivia. It was first isolated by German chemist Albert Niemann in the early 1800s. Its early uses were in surgery to numb nose and throat areas. It was useful in these areas specifically because it constricts blood vessels and helps stop blood flow as well as acting as an anesthetic. Cocaine was also studied by Sigmund Freud who proposed using it as a treatment for depression, alcoholism, and morphine addiction. It was sold in pharmacies in Canada as a tonic until around 1911 when it was outlawed and did not return to popularity until the 1960s.
Cocaine is sold on the street illicitly as a white crystalline powder or in off-white chunks. Before final sale, it is usually diluted (i.e. cut) with fillers to increase the volume, and thereby the final profits. It is rarely smoked, but is most often injected, for a high within 15-30 seconds, or snorted, for a high within 3-5 minutes. The crack form of cocaine can be smoked for an almost immediate high. The physiological effects of cocaine depend upon the amount of cocaine ingested, ingestion method, and prior drug use. Usual effects of the drug are feelings of euphoria, extra energy, and alertness. Negative effects of the drug include contemplativeness, accelerated heartbeat, high blood pressure, seizures, respiratory failure, stroke, and heart failure. Repeated use leads to restlessness, excitability, insomnia, paranoia, hallucinations, and symptoms similar to schizophrenia. Repeated use can cause mood swings, loss of sexual desire, weight loss, and insomnia.[1,2] It is estimated that 1.3 million people in the United States use cocaine every month. Occasional usage is down to 3 million from the 1985 usage high of 8.5 million. Weekly usage has remained relatively constant at 500,000 since 1985.
Addiction to cocaine occurs when the structure of the brain is permanently changed by use of the drug. Cocaine alters the circuits in the brain which are involved in emotions and free will. Cocaine works by altering the behavior of a neurotransmitter called dopamine. Dopamine is responsible for feelings of happiness, body movement, judgment, and motivation. Cocaine utilizes the same receptor in the brain as dopamine does, so when cocaine is present there is an excess of dopamine with no site to bind to. This causes feelings of pleasure and encourages drug use. The dopamine effect and the constricting of arteries and blood vessels shows a cumulative effect that correlates to the length and intensity of drug use. Cocaine-induced binges are also understood via the biochemistry of dopamine. Dopamine controls impulses for eating, drinking, sleeping, and sex. When dopamine pathways are disturbed, the impulse to stop a behavior is hindered. Thus, when cocaine is present, the dopamine is ineffective in its effort to tell the body when it has had enough. The craving for cocaine continues because of the lack of the cessation impulse. It has been found that drug users do not become tolerant to cocaine or need to increase their dosage. They actually become more sensitive to the drug as their brains are further changed by extended use. The dependence on cocaine is therefore more psychological than it is physical. Cocaine is central to the thoughts, emotions, and activities of the user and this emotional dependence is what causes cravings. Abstinence from cocaine in a regular user can cause insomnia, eating disorders, depression, anxiety, and cravings.