Crack cocaine

Crack cocaine, commonly known simply as crack, and also known as rock, is a free base form of the stimulant cocaine that can be smoked. Crack offers a short, intense high to smokers. The Manual of Adolescent Substance Abuse Treatment calls it the most addictive form of cocaine.
Crack cocaine first saw widespread use as a recreational drug in primarily impoverished neighborhoods in New York City, Philadelphia, Baltimore, Washington, D.C., Los Angeles, San Francisco and Miami in late 1984 and 1985. This rapid increase in use and availability was named the "crack epidemic", which began to wane in the 1990's.
The drug creates quick effects when smoked. Crack cocaine takes five to ten seconds before symptoms are shown. Short-term effects of the drug include euphoria, hyper-focus, sociability, cardiovascular hypertension, dilated pupils, hyperthermia, vertigo, tremors, restlessness. Repeated use can lead to respiratory failure, seizures, CNS depression, and cardiomyopathy. The drug also tends to cause users to develop paranoia, delusions of bugs under their skin, and in high doses, psychosis.
Crack cocaine and salt-based cocaine are both classified by the Drug Enforcement Administration as Schedule II drugs under the Controlled Substances Act.

Terminology

The origin of the name "crack" comes from the "crackling" sound that is produced when the cocaine and its impurities are heated past the point of vaporization.
It is also commonly called "rock" on the street, a name that comes from its physical appearance after processing. When bulk quantities of powdered cocaine are mixed with baking soda or ammonia and water, then heated, it forms small, hard, solid crystals or pellets that resemble rocks.

Chemistry

As the name implies, "freebase" is the base form of cocaine, as opposed to the salt form. It is practically insoluble in water whereas hydrochloride salt is water-soluble.
Smoking freebase cocaine has the additional effect of releasing methylecgonidine into the user's system due to the pyrolysis of the substance. Some research suggests that smoking freebase cocaine can be even more cardiotoxic than other routes of administration because of methylecgonidine's effects on lung tissue and liver tissue.
Pure cocaine is prepared by neutralizing its compounding salt with an alkaline solution, which will precipitate non-polar basic cocaine. It is further refined through aqueous-solvent liquid–liquid extraction.
Purer forms of crack resemble off-white, jagged-edged "rocks" of a hard, brittle plastic, with a slightly higher density than candle wax. Like cocaine in other forms, crack rock acts as a local anesthetic, numbing the tongue or mouth only where directly placed. Purer forms of crack will sink in water and melt at the edges when near a flame.
Crack cocaine sold on the streets may be adulterated with other substances mimicking the appearance of crack to increase bulk. Use of toxic adulterants such as levamisole, a drug used to treat parasitic worm infections, has been documented.

Synthesis

is a base used in the preparation of crack, although other weak bases may substitute for it.
The net reaction when using sodium bicarbonate is
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, 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 in a reversible acid-base reaction. The heating accelerates the degradation of carbonic acid into carbon dioxide 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, much lower than the cocaine hydrochloride melting point of 190 °C. Whereas cocaine hydrochloride cannot be smoked,
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. Harm reduction and public health agencies may distribute packets of citric acid or ascorbic acid for this purpose.

Recreational use

Effects of crack cocaine include euphoria, supreme confidence, loss of appetite, insomnia, alertness, increased energy, a craving for more cocaine,
and paranoia.
Its initial effect is to release a large amount of dopamine, a brain chemical inducing feelings of euphoria. The high usually lasts from five to ten minutes, after which time dopamine levels in the brain plummet, leaving the user feeling depressed and low. When 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.
In a 2000 Brookhaven National Laboratory medical department study, based on self-reports of 32 people who used cocaine who participated in the study, "peak high" was found at a mean of 1.4 ± 0.5 minutes.
The onset of cocaine's euphoric effects is fastest with inhalation, beginning after 3–5 seconds. The drug is then quickly transported to the brain, where it acts on the central nervous system, producing an almost immediate "high" that can be very powerful – this initial crescendo of stimulation known as a rush. This is followed by an equally intense low, leaving the user craving more of the drug. Addiction to crack usually occurs within four to six weeks – much more rapidly than regular cocaine.

Route of administration

Crack cocaine is usually heated in a drug pipe until sublimation occurs at a relatively low temperature and the vapor is inhaled. This process is commonly referred to as "freebasing." Although commonly called "smoking," this method actually involves vaporizing the drug rather than burning it. If crack cocaine is burned directly, such as in a regular tobacco pipe, roll-your-own cigarette, or aluminum foil higher temperatures may lead to decomposition of the active compound, reducing its effectiveness. This is why vaporization at lower temperatures, rather than combustion, is the preferred method for administration. While no formal studies have specifically quantified the extent of drug loss during combustion, users commonly choose to vaporize crack cocaine in order to maximize its effects and potentially avoid wasting money. Additionally, vaporizing is generally considered less harsh on the throat and lungs compared to smoking crack through a tobacco pipe, as combustion can produce more irritating and toxic by-products.
Pyrolysis products of cocaine that occur only when heated/smoked have been shown to change the effect profile, i.e. anhydroecgonine methyl ester, when co-administered with cocaine, increases the dopamine in CPu and NAc brain regions, and has M₁ — and M₃ — receptor affinity.
The effects felt almost immediately after inhaled are very intense and do not last long — usually 2 to 10 minutes. When smoked, cocaine is sometimes combined with other drugs, such as cannabis, often rolled into a joint or blunt.

Love rose

People often freebase crack with a pipe made from a small glass tube, often taken from "love roses", small glass tubes with a paper rose that are promoted as romantic gifts. These are sometimes called "stems", "horns", "blasters" and "straight shooters". A small piece of clean heavy copper or occasionally stainless steel scouring padoften called a "brillo" or "chore" serves as a reduction base and flow modulator in which the "rock" can be melted and boiled to vapor. Crack is smoked by placing it at the end of the pipe; a flame held close to it produces vapor, which is then inhaled by the smoker.

Adverse effects

Physiological

Incidental exposure of the eye to sublimated cocaine while smoking crack cocaine can cause serious injury to the cornea and long-term loss of visual acuity.
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 free base 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.

Toxic adulterants: Many substances may have been added to expand the weight and volume of a batch, while still appearing to be pure crack. Occasionally, highly toxic substances are used, with a range of corresponding short and long-term health risks. Adulterants used with crack and cocaine include milk powder, sugars such as glucose, starch, caffeine, lidocaine, benzocaine, paracetamol, amphetamine, scopolamine and strychnine.
Smoking problems: Any route of administration poses its own set of health risks; in the case of crack cocaine, smoking tends to be more harmful than other routes. Crack users tend to smoke the drug because that has a higher bioavailability than other routes typically used for drugs of abuse, such as insufflation. Crack has a melting point of around , and the smoke does not remain potent for long. Therefore, crack pipes are generally very short, to minimize the time between evaporating and ingestion. Having a very hot pipe pressed against the lips often causes cracked and blistered lips, colloquially known as "crack lip". The use of "convenience store crack pipes"—glass tubes which originally contained small artificial roses—may contribute to this condition. These 4-inch pipes are not durable and will quickly develop breaks; users may continue to use the pipe even though it has been broken to a shorter length. The hot pipe might burn the lips, tongue, or fingers, especially when passed between people who take hits in rapid succession, causing the short pipe to reach higher temperatures than if used by one person alone.
Pure or large doses: Because the quality of crack can vary greatly, some people might smoke larger amounts of diluted crack, unaware that a similar amount of a new batch of purer crack could cause an overdose. This can trigger heart problems or cause unconsciousness.
Pathogens on pipes: When pipes are shared, bacteria or viruses can be transferred from person to person.

Crack cocaine causes DNA damage in multiple organs of rats and mice.