Cocaine is a potent central nervous system stimulant derived from the leaves of the coca plant, primarily two species native to South America: Erythroxylum coca and E. novogranatense. The active alkaloid, cocaine, is chemically extracted from these leaves and typically converted into a white, crystalline powder known as cocaine hydrochloride. This physical form of the drug dictates the method of administration and the subsequent pathway cocaine takes to be absorbed into the bloodstream and reach the brain. The route of entry determines how quickly the drug’s effects begin, how long they last, and the overall intensity experienced by the user.
Entry Through the Nasal Passages
The administration of cocaine powder through the nasal passages, a process known as insufflation or “snorting,” relies on the drug being absorbed through the thin mucous membranes lining the nasal cavity. The nasal lining is richly supplied with small blood vessels, which allows the cocaine to diffuse relatively quickly into the capillaries and then enter the systemic circulation. However, this route of entry is complicated by one of cocaine’s unique pharmacological properties: its function as a powerful vasoconstrictor.
Cocaine causes the blood vessels in the nasal tissue to constrict, which immediately limits the blood flow to the area. This self-limiting action slows the rate at which the drug can be absorbed into the bloodstream, making insufflation a less efficient process than other methods. While a significant amount of cocaine is absorbed through the mucosa, a portion of the powder may drip down the back of the throat and be swallowed, leading to absorption through the digestive system. The bioavailability, or the amount of drug that reaches the bloodstream intact, is generally estimated to be between 60% and 80% for this route.
Chronic vasoconstriction and irritation from the powdered drug can cause localized tissue damage over time. Repeated insufflation can lead to the erosion of the nasal septum, potentially resulting in a perforated septum. Because absorption is slowed by vasoconstriction, the onset of effects is not instantaneous; peak plasma concentrations are typically achieved within 30 to 60 minutes after administration.
Entry Through the Lungs
The inhalation of cocaine vapor, commonly achieved by smoking freebase or crack cocaine, provides the most rapid pathway for the drug to reach the brain. This method bypasses the slower absorption barriers of the nasal or digestive tracts entirely. When the cocaine is heated, it vaporizes, and the user inhales this vapor directly into the lungs.
The lungs are an extremely efficient organ for drug absorption due to the massive surface area of the millions of tiny air sacs, called alveoli. The alveoli are enveloped by a dense network of capillaries, forming the pulmonary circulation. This arrangement means that the drug molecules only have to cross a very thin membrane layer before entering the bloodstream.
Once absorbed into the pulmonary capillaries, the cocaine-rich blood travels directly to the heart’s left side. From there, the heart pumps this blood immediately and forcefully to the brain. This direct, high-speed route to the central nervous system results in the fastest and most intense onset of psychoactive effects, often within five to ten seconds. The rapid delivery produces an intense, short-lived rush or euphoria, contributing to the high addictive potential associated with smoking cocaine.
Direct Entry into the Bloodstream
Intravenous (IV) injection involves dissolving cocaine hydrochloride powder in water and injecting the solution directly into a vein. This method completely bypasses all the body’s natural absorption barriers, such as the skin, mucosa, and digestive lining. The drug is delivered straight into the venous circulation, leading to immediate distribution throughout the body.
IV administration offers 100% bioavailability, meaning the entire administered dose of the active drug enters the systemic circulation. This efficiency ensures that the maximum possible concentration of cocaine reaches the brain. While the onset is nearly instantaneous, the speed is marginally slower than inhalation because the solution must travel from the peripheral vein, through the heart, and then to the brain. The onset of effects is extremely rapid, with peak subjective effects typically reached within a few minutes. The instantaneous delivery of the full dose produces a profound and intense initial effect, which is a major factor in the high-risk profile of this route.
Entry Through the Digestive System
Oral ingestion, whether by swallowing cocaine powder, consuming it in a liquid, or chewing coca leaves, is the least efficient route of entry for the active drug. When swallowed, the cocaine must first travel through the digestive tract. The drug must survive the acidic environment of the stomach and then be absorbed through the lining of the small intestine.
Absorption is poor because a significant amount of the drug is metabolized before it can reach the general circulation. Once absorbed from the gut, the cocaine-rich blood travels via the portal vein directly to the liver. This process is known as first-pass metabolism, where the liver’s enzymes break down a large fraction of the drug into inactive metabolites. The mean oral bioavailability is low, typically ranging from about 30% to 45%. This combination of slow absorption and extensive metabolism results in a slow and significantly milder effect compared to other routes.