Cocaine and the Nervous System

Commonly known as “coke,” “blow” and “snow,” cocaine is a drug made from the leaves of the coca plant. It can be used medically as a topical anesthetic, but is most widely used recreationally as a stimulant. When used for recreational purposes, cocaine is typically sold in powdered form, which is snorted or burned and inhaled as smoke. Some coke users mix the powder into a solution and inject it into a vein. Drug dealers often mix the powdered version of coke with other white, powdery substances like flour, cornstarch or other drugs — substances that are unknown to the user and can cause unexpected effects. As an illicit drug, coke is also solidified into crystalline rock form, which is sold as “crack” cocaine. Crack users heat and smoke the rock crystals, a process that makes a crackling sound and leads to very rapid, short-acting effects. Considered 75% more potent than powdered cocaine, crack’s short-acting effects are more intense and can lead to addiction after one use.

Brain’s Reward Circuit and Cocaine Effects on the Brain

Cocaine affects the central nervous system, which includes the brain, spinal cord and nerves. When this powerful stimulant travels through the bloodstream and reaches the brain, it impacts the brain’s reward circuit. The coke catalyzes signals that are “neurotransmitted” along the brain’s reward circuit pathways where they are mediated and interpreted. When cocaine travels along these pathways, it triggers an excessive release of dopamine, a neurotransmitter that regulates motivation, pleasure and reward. The cocaine-triggered dopamine is rapidly flushed into certain sections of the brain in a series of communications that transmit signals through the nervous system. This mechanism leads to an invigorating rush or “high” for most users, boosting their mood and making them feel euphoric, energetic and self-confident. The pleasurable cocaine effects on the brain make the drug highly addictive.

A Key to Understanding Cocaine Addiction

The feeling of grandiosity and the boost of energy that many users experience with cocaine motivates them to want to use it again, thinking that continued use of the drug will help them stay alert to study or will improve their performance at work. Because coke also temporarily speeds up the body and suppresses the appetite, many people use it to lose weight. Cocaine tends to be abused because it interferes with the brain’s normal communication process in a way that is habit-forming. Coke actually alters the brain by blocking the removal of dopamine by binding to the reward center’s dopamine transporters. With repeated use, this can result in a buildup of dopamine in the brain’s synapses. The dopamine buildup leads to overstimulation of receiving neurons in the brain’s reward circuitry, which makes users seek more cocaine in an attempt to maintain that level of stimulation.

Cocaine’s Other Effects

Cocaine has other effects that are less desirable or pleasurable and can lead to problems. Some of the unwanted or negative effects of cocaine include constricted blood vessels, dilated pupils, runny nose, tremors, muscle twitches, dizziness, restlessness, jumpiness, irritability, anxiety, paranoia, and even panic attacks. Higher doses can lead to erratic behavior that is combative or violent. Coke users also can experience an increased heart rate and heart palpitations, and run the risk of having a heart attack, respiratory arrest or stroke, even with just one use. These negative side effects can occur even if users are young and generally healthy. Cocaine’s effects on the brain also lead to impaired judgment and risky behavior, such as combining it with alcohol or other drugs, using shared needles or having unsafe sex which, in turn, can result in hepatitis or sexually transmitted diseases like HIV/AIDS. Overcoming cocaine addiction is possible with proper substance abuse treatment. Effective treatment must be of a long enough duration to ensure that the drug is completely detoxed or eradicated from the system, that the drug user develops new tools for staying drug-free, and the brain’s reward circuit and nervous system have a chance to return to their normal state, which can take several weeks. Sources: Cocaine. National Institute on Drug Abuse, NIH, February 2016. Understanding Drug Abuse and Addiction: What Science Says. National Institute on Drug Abuse, NIH, February 2016.  The Truth About Crack Cocaine. Foundation for a Drug-Free World, 2017. Cocaine. Medline Plus. NIH, U.S. National Library of Medicine, March 2017.

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