Crack cocaine, also known simply as crack, is a free base form of cocaine that can be smoked. Crack offers a short but intense high to smokers. The Manual of Adolescent Substance Abuse Treatment calls it the most "addictive" (effective) form of cocaine. Crack cocaine is commonly used as a recreational drug. Crack first saw widespread use in primarily impoverished inner city neighborhoods in New York, Los Angeles, and Miami in late 1984 and 1985; its rapid increase in use and availability is sometimes termed as the "crack epidemic".
In purer forms, crack rocks appear as off-white nuggets with jagged edges, with a slightly higher density than candle wax. Purer forms of crack resemble a hard brittle plastic, in crystalline form (snaps when broken). A crack rock acts as a local anesthetic (see: cocaine), numbing the tongue or mouth only where directly placed. Purer forms of crack will sink in water or melt at the edges when near a flame (crack vaporizes at 90 °C, 194 °F).
Crack cocaine as sold on the streets may be adulterated or "cut" with other substances mimicking the appearance of crack cocaine to increase bulk. Use of toxic adulterants such as levamisole has been documented.
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With Ammonium bicarbonate:
With Ammonium carbonate:
Crack cocaine is frequently purchased already in rock form, although it is not uncommon for some users to "wash up" or "cook" powder cocaine into crack themselves. This process is frequently done with baking soda (sodium bicarbonate), water, and a spoon. Once mixed and heated, the bicarbonate reacts with the hydrochloride of the powder cocaine, forming free base cocaine and carbonic acid (H2CO3) in a reversible acid-base reaction. The heating accelerates the degradation of carbonic acid into carbon dioxide (CO2) and water. Loss of CO2 prevents the reaction from reversing back to cocaine hydrochloride. Free base cocaine separates as an oily layer, floating on the top of the now leftover aqueous phase. It is at this point that the oil is picked up rapidly, usually with a pin or long thin object. This pulls the oil up and spins it, allowing air to set and dry the oil, and allows the maker to roll the oil into the rock-like shape.
Crack vaporizes near temperature 90 °C (194 °F), much lower than the cocaine hydrochloride melting point of 190 °C (374 °F). Whereas cocaine hydrochloride cannot be smoked (burns with no effect),crack cocaine when smoked allows for quick absorption into the blood stream, and reaches the brain in 8 seconds. Crack cocaine can also be injected intravenously with the same effect as powder cocaine. However, whereas powder cocaine dissolves in water, crack must be dissolved in an acidic solution such as lemon juice or white vinegar, a process that effectively reverses the original conversion of powder cocaine to crack.
Crack cocaine is commonly used as a recreational drug. Effects of crack cocaine include euphoria, supreme confidence, loss of appetite, insomnia, alertness, increased energy, a craving for more cocaine, and potential paranoia (ending after use). Its initial effect is to release a large amount of dopamine, a brain chemical inducing feelings of euphoria. The high usually lasts from 5-10 minutes, after which time dopamine levels in the brain plummet, leaving the user feeling depressed and low. When (powder) cocaine is dissolved and injected, the absorption into the bloodstream is at least as rapid as the absorption of the drug which occurs when crack cocaine is smoked, and similar euphoria may be experienced.
Because crack is an illicit drug, users may consume impure or fake ("bunk") drug, which may pose additional health risks.
The short-term physiological effects of cocaine include constricted blood vessels, dilated pupils, and increased temperature, heart rate, and blood pressure. Some users of cocaine report feelings of restlessness, irritability, and anxiety. In rare instances, sudden death can occur on the first use of cocaine or unexpectedly thereafter. Cocaine-related deaths are often a result of cardiac arrest or seizures followed by respiratory arrest.
Like other forms of cocaine, smoking crack can increase heart rate and blood pressure, leading to long-term cardiovascular problems. Some research suggests that smoking crack or freebase cocaine has additional health risks compared to other methods of taking cocaine. Many of these issues relate specifically to the release of methylecgonidine and its effect on the heart, lungs, and liver.
In crack users, acute respiratory symptoms have been reported, sometimes termed crack lung. Symptoms include fever, hemoptysis and difficulty breathing. In the 48-hour period after use, people with these symptoms have also had associated radiographic findings on chest xray of pulmonary edema, interstitial pneumonia, diffuse alveolar hemorrhage, and eosinophil infiltration.
Stimulant drug abuse (particularly amphetamine and cocaine) can lead to delusional parasitosis (aka Ekbom's Syndrome: a mistaken belief they are infested with parasites). For example, excessive cocaine use can lead to formication, nicknamed "cocaine bugs" or "coke bugs", where the affected people believe they have, or feel, parasites crawling under their skin. (Similar delusions may also be associated with high fever or in connection with alcohol withdrawal, sometimes accompanied by visual hallucinations of insects.)
Paranoia and anxiety are among the most common psychological symptoms of crack cocaine use. Psychosis is more closely associated with smoking crack cocaine than intranasal and intravenous use. 
"Crack baby" is a term for a child born to a mother who used crack cocaine during her pregnancy. The threat that cocaine use during pregnancy poses to the fetus is now considered exaggerated. Studies show that prenatal cocaine exposure (independent of other effects such as, for example, alcohol, tobacco, or physical environment) has no appreciable effect on childhood growth and development. However, the official opinion of the National Institute on Drug Abuse of the United States warns about health risks while cautioning against stereotyping:
Many recall that "crack babies", or babies born to mothers who used crack cocaine while pregnant, were at one time written off by many as a lost generation. They were predicted to suffer from severe, irreversible damage, including reduced intelligence and social skills. It was later found that this was a gross exaggeration. However, the fact that most of these children appear normal should not be over-interpreted as indicating that there is no cause for concern. Using sophisticated technologies, scientists are now finding that exposure to cocaine during fetal development may lead to subtle, yet significant, later deficits in some children, including deficits in some aspects of cognitive performance, information-processing, and attention to tasks--abilities that are important for success in school.
There are also warnings about the threat of breastfeeding: "It is likely that cocaine will reach the baby through breast milk." The March of Dimes advises the following regarding cocaine use during pregnancy:
Cocaine use during pregnancy can affect a pregnant woman and her unborn baby in many ways. During the early months of pregnancy, it may increase the risk of miscarriage. Later in pregnancy, it can trigger preterm labor (labor that occurs before 37 weeks of pregnancy) or cause the baby to grow poorly. As a result, cocaine-exposed babies are more likely than unexposed babies to be born with low birthweight (less than 5.5 lb or 2.5 kg). Low-birthweight babies are 20 times more likely to die in their first month of life than normal-weight babies, and face an increased risk of lifelong disabilities such as mental retardation and cerebral palsy. Cocaine-exposed babies also tend to have smaller heads, which generally reflect smaller brains. Some studies suggest that cocaine-exposed babies are at increased risk of birth defects, including urinary-tract defects and, possibly, heart defects. Cocaine also may cause an unborn baby to have a stroke, irreversible brain damage, or a heart attack.
An appreciable tolerance to cocaine's high may develop, with many addicts reporting that they seek but fail to achieve as much pleasure as they did from their first experience. Some users will frequently increase their doses to intensify and prolong the euphoric effects. While tolerance to the high can occur, users might also become more sensitive (drug sensitization) to cocaine's local anesthetic (pain killing) and convulsant (seizure inducing) effects, without increasing the dose taken; this increased sensitivity may explain some deaths occurring after apparent low doses of cocaine.
Crack cocaine is popularly thought to be the most addictive form of cocaine. However, this claim has been contested: Morgan and Zimmer wrote that available data indicated that "...smoking cocaine by itself does not increase markedly the likelihood of dependence.... The claim that cocaine is much more addictive when smoked must be reexamined." They argued that cocaine users who are already prone to abuse are most likely to "move toward a more efficient mode of ingestion" (that is, smoking).
The intense desire to recapture the initial high is what is so addictive for many users. On the other hand, Reinarman et al. wrote that the nature of crack addiction depends on the social context in which it is used and the psychological characteristics of users, pointing out that many heavy crack users can go for days or weeks without using the drugs.
A typical response among users is to have another hit of the drug; however, the levels of dopamine in the brain take a long time to replenish themselves, and each hit taken in rapid succession leads to progressively less intense highs. However, a person might binge for 3 or more days without sleep, while inhaling hits from the pipe.
Use of cocaine in a binge, during which the drug is taken repeatedly and at increasingly high doses, leads to a state of increasing irritability, restlessness, and paranoia. This may result in a full-blown paranoid psychosis, in which the individual loses touch with reality and experiences auditory hallucinations.
Large amounts of crack cocaine (several hundred milligrams or more) intensify the user's high, but may also lead to bizarre, erratic, and violent behavior. Large amounts can induce tremors, vertigo, muscle twitches, paranoia, or, with repeated doses, a toxic reaction closely resembling amphetamine poisoning.
atari; base; bazooka; beamers; beemers; bebe; bee-bee; berry; bing; bolo; bomb; boulder; boulders; butter; caine; cane; Casper; Casper the ghost; cavvy; chemical; chewies; cloud; cloud nine; crills; crunch and munch; dip; famous dimes; fan; fish scale; fries; fry; glo; golfball; gravel; grit; hail; hamburger; helper; hubba; ice cube; kangaroo; kibbles and bits; kibbles; krills; lightem; paste; patico; pebbles; pee wee; pony; raw; ready; ready rocks; redi rocks; roca; rock; rooster; rox; Roxanne; scud; Scotty; scramble; scruples; seven-up; sherm; sherms; sleet; snowballs; stones; teeth; tension; top gun; tweak; ultimate; wash; white cloud; work; yahoo; yay; yayoo; yeah-O; yeyo; yeo; yuck.
Crack cocaine may be combined with amphetamine ("croack"); tobacco ("coolie"); marijuana ("buddha"; "caviar"; "chronic"; "cocoa puffs"; "fry daddy"; "gimmie"; "gremmie"; "juice"; "primo"; "torpedo"; "turbo"; "woolie"; "woola"); heroin ("moon rock"); and phencyclidine ("clicker"; "p-funk"; "spacebase").
Crack smoking ("hitting the pipe"; "puffing"; "beaming up (to Scotty)") is commonly performed with utensils such as pipes ("bowl"; "devil's dick"; "glass dick"; "horn"; "Uzi"); improvised pipes made from a plastic bottle ("Masarati"); water pipes ("bong"; "hubbly-bubbly"); and laboratory pipettes ("demo").
Cocaine is listed as a Schedule I drug in the United Nations 1961 Single Convention on Narcotic Drugs, making it illegal for non-state-sanctioned production, manufacture, export, import, distribution, trade, use and possession. In most states (except in the U.S.) crack falls under the same category as cocaine.
In Australia, crack falls under the same category as cocaine, which is listed as a Schedule 8 controlled drug, indicating that any substances and preparations for therapeutic use under this category have high potential for abuse and addiction. It is permitted for some medical use, but is otherwise outlawed.
As a Schedule I substance under the Controlled Drugs and Substances Act, crack is not differentiated from cocaine and other coca products. However, the court may weigh the socio-economic factors of crack usage in sentencing. As a guideline, Schedule I drugs carry a maximum 7-year prison sentence for possession for an indictable offense and up to life imprisonment for trafficking and production. A summary conviction on possession carries a $1000-$2000 fine and/or 6 months to a year imprisonment.
In the United States, cocaine is a Schedule II drug under the Controlled Substances Act, indicating that it has a high abuse potential but also carries a medicinal purpose. Under the Controlled Substances Act, crack and cocaine are considered the same drug.
The Anti-Drug Abuse Act of 1986 increased penalties for crack cocaine possession and usage. It mandated a mandatory minimum sentence of five years without parole for possession of five grams of crack; to receive the same sentence with powder cocaine one had to have 500 grams. This sentencing disparity was reduced from 100-to-1 to 18-to-1 by the Fair Sentencing Act of 2010.