cocaine

cocaine, white crystalline alkaloid that is obtained from the leaves of the coca plant (Erythroxylum coca), a bush commonly found growing wild in Peru, Bolivia, and Ecuador and cultivated in many other countries. The chemical formula of cocaine is C₁₇H₂₁NO₄.

Forms and use

As a fine white powder, cocaine is snorted and is readily absorbed into the bloodstream through the nasal mucous membranes. Because it is an irritant, however, and acts to constrict blood vessels, users typically have a chronic runny nose or, in severe cases, develop ulcerations in the nasal cavity.

Cocaine is also injected in solution or smoked in a chemically treated form known as freebase; either of these methods produces a markedly more compulsive use of the drug. In the 1980s a new preparation of cocaine appeared, called crack; the smoking of crack produces an even more intense and even more short-lived euphoria that is extremely addicting. This form of cocaine consumption is also the most detrimental to health. Another smokable and highly addictive form is cocaine paste, which is an intermediate stage in the processing of coca leaves into cocaine.

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Physiological effects

Cocaine acts as both a psychoactive stimulant and a local anesthetic through distinct, concurrent actions on the nervous system. Its local anesthetic effects stem from its ability to block voltage-gated sodium channels in peripheral nerves, which prevents nerve impulses from being conducted. This leads to numbness in areas such as the nose or throat. In contrast, cocaine’s stimulant effect on the central nervous system (CNS) results from its ability to block the reuptake of neurotransmitters such as dopamine, norepinephrine, and serotonin by neurons in the brain. This leads to increased signaling in neural pathways and heightened CNS activity.

The buildup of dopamine in brain regions associated with reward is linked to intense feelings of well-being and euphoria, while increased norepinephrine activity contributes to heightened alertness, reduced fatigue, and suppressed appetite. However, with larger doses or repeated use of cocaine, these same systems become dysregulated. The brain’s reward pathways become less responsive, which can lead to depression and fatigue when the drug is not present. Overstimulation of the CNS can also cause anxiety, irritability, insomnia, chronic fatigue, and paranoia; excessive neural activity may trigger confusion, seizures (convulsions), and potentially fatal outcomes.

The short-lived euphoric effects of cocaine are closely linked to its high potential for addiction. Because the pleasurable “high” fades quickly—often within about 30 minutes—users may feel a strong urge to take repeated doses in a short period to maintain those effects. This pattern, sometimes described as binge use, increases the frequency of drug exposure to the brain’s reward system. Some users develop a toxic psychosis, involving paranoid delusions and disturbing tactile hallucinations, such as the sensation of insects crawling under the skin.

Extraction and refinement

For centuries the Indigenous peoples of Peru and Bolivia have chewed coca leaves mixed with pellets of limestone or plant ashes for pleasure or in order to withstand strenuous working conditions, hunger, and thirst. In other cultures the active alkaloid is chemically extracted from coca leaves and refined to form cocaine hydrochloride, the white powder commonly known as cocaine. This powder can be further processed into other forms, such as crack cocaine, by altering its chemical structure.

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Illicit use

Cocaine use, which had been a marginal drug problem throughout much of the 20th century, grew alarmingly in the late 20th century in several countries and has since accounted for a significantly larger share of drug-induced deaths. Cocaine remains one of the most widely used illegal stimulants, with use concentrated in regions such as North America, Europe, and parts of South America, though it has expanded into new markets in recent years. A major concern today is the contamination of cocaine with synthetic opioid drugs such as fentanyl, which render its effects far more unpredictable and dangerous.