Cocaine (from French: cocaïne, from Spanish: coca, ultimately from Quechua: kúka) is a stimulant drug obtained from the leaves of two Coca species native to South America, Erythroxylum coca and Erythroxylum novogranatense. After extraction from coca leaves and further processing into cocaine hydrochloride (powdered cocaine), the drug may be snorted, heated until sublimated and then inhaled, or dissolved and injected into a vein. Cocaine stimulates the reward pathway in the brain. Mental effects may include an intense feeling of happiness, sexual arousal, loss of contact with reality, or agitation. Physical effects may include a fast heart rate, sweating, and dilated pupils. High doses can result in high blood pressure or high body temperature. Effects begin within seconds to minutes of use and last between five and ninety minutes. As cocaine also has numbing and blood vessel constriction properties, it is occasionally used during surgery on the throat or inside of the nose to control pain, bleeding, and vocal cord spasm.Cocaine crosses the blood-brain barrier via a proton-coupled organic cation antiporter and (to a lesser extent) via passive diffusion across cell membranes. Cocaine blocks the dopamine transporter, inhibiting reuptake of dopamine from the synaptic cleft into the pre-synaptic axon terminal; the higher dopamine levels in the synaptic cleft increase dopamine receptor activation in the post-synaptic neuron, causing euphoria and arousal.
Cocaine can cause involuntary tooth grinding, known as bruxism, which can deteriorate tooth enamel and lead to gingivitis. Additionally, stimulants like cocaine, methamphetamine, and even caffeine cause dehydration and dry mouth. Since saliva is an important mechanism in maintaining ones oral pH level, people who use cocaine over a long period of time who do not hydrate sufficiently may experience demineralization of their teeth due to the pH of the tooth surface dropping too low (below 5.5). Cocaine use also promotes the formation of blood clots. This increase in blood clot formation is attributed to cocaine-associated increases in the activity of plasminogen activator inhibitor, and an increase in the number, activation, and aggregation of platelets.Chronic intranasal usage can degrade the cartilage separating the nostrils (the septum nasi), leading eventually to its complete disappearance. Due to the absorption of the cocaine from cocaine hydrochloride, the remaining hydrochloride forms a dilute hydrochloric acid.Illicitly-sold cocaine may be contaminated with levamisole. Levamisole may accentuate cocaines effects. Levamisole-adulterated cocaine has been associated with autoimmune disease.Cocaine use leads to an increased risk of hemorrhagic and ischemic strokes. Cocaine use also increases the risk of having a heart attack. Addiction
Relatives of persons with cocaine addiction have an increased risk of cocaine addiction. Cocaine addiction occurs through ΔFosB overexpression in the nucleus accumbens, which results in altered transcriptional regulation in neurons within the nucleus accumbens. ΔFosB levels have been found to increase upon the use of cocaine. Each subsequent dose of cocaine continues to increase ΔFosB levels with no ceiling of tolerance.