Crack cocaine in the context of "Stimulant"

Smoking is a human behavior which involves the combustion of a substance, usually plant material, and the inhalation of resulting fumes. Today smoking is mostly practiced by rolling the dried leaves of the tobacco plant into a cigarette. Other forms of tobacco smoking include the use of a smoking tobacco with a pipe or cigar, or using a bong. Cigarette smokers almost always inhale the smoke; most pipe and cigar smokers do not inhale.

Smoking is primarily practiced as a route of administration for psychoactive chemicals because the active substances within the burnt, dried plant leaves (or other chemical) can vaporize into a gaseous state and be delivered into the respiratory tract, where they are rapidly absorbed into the bloodstream through the lungs and can reach the central nervous system. In the case of tobacco smoking, these active substances are a mixture of aerosol particles that include the pharmacologically active alkaloid nicotine, which stimulates the nicotinic acetylcholine receptors in the brain, and other non-psychoactive chemicals that result from combustion. Other notable drugs inhaled via smoking include tetrahydrocannabinol (from cannabis), morphine (from opium) cocaine (from crack), and methamphetamine. Designer drugs, or "research chemicals", can also be smoked.

A psychoactive drug, psychopharmaceutical, mind-altering drug, consciousness-altering drug, psychoactive substance, or psychotropic substance is a chemical substance that alters psychological functioning by modulating central nervous system (CNS) activity. Psychoactive and psychotropic drugs both affect the brain, with psychotropics sometimes referring to psychiatric drugs or high-abuse substances, while “drug” can have negative connotations. Novel psychoactive substances are designer drugs made to mimic illegal ones and bypass laws.

Psychoactive drug use dates back to prehistory for medicinal and consciousness-altering purposes, with evidence of widespread cultural use. Many animals intentionally consume psychoactive substances, and some traditional legends suggest animals first introduced humans to their use. Psychoactive substances are used across cultures for purposes ranging from medicinal and therapeutic treatment of mental disorders and pain, to performance enhancement. Their effects are influenced by the drug itself, the environment, and individual factors. Psychoactive drugs are categorized by their pharmacological effects into types such as anxiolytics (reduce anxiety), empathogen–entactogens (enhance empathy), stimulants (increase CNS activity), depressants (decrease CNS activity), and hallucinogens (alter perception and emotions). Psychoactive drugs are administered through various routes—including oral ingestion, injection, rectal use, and inhalation—with the method and efficiency differing by drug.

Cocaine is a central nervous system stimulant and tropane alkaloid derived primarily from the leaves of two coca species native to South America: Erythroxylum coca and E. novogranatense. Coca leaves are processed into cocaine paste, a crude mix of coca alkaloids from which cocaine base is isolated and converted to cocaine hydrochloride. Cocaine was once a standard topical medication as a local anesthetic with intrinsic vasoconstrictor activity, but its high abuse potential, adverse effects, and cost have limited its use and led to its replacement by other medicines.

Street cocaine is commonly snorted, injected, or smoked as crack cocaine, with effects lasting up to 90 minutes depending on the route. Cocaine acts pharmacologically as a serotonin–norepinephrine–dopamine reuptake inhibitor (SNDRI), producing reinforcing effects such as euphoria, increased alertness, concentration, libido, and reduced fatigue and appetite.