Clinical Textbook of Addictive Disorders 3rd ed - R. Frances, S. Miller, A. Mack (Guilford, 2005) WW

9. Cocaine and Stimulants 187Cocaine sulfate (paste) is the intermediate form between the coca leaf andthe finished cocaine hydrochloride crystal. The smoking of coca paste, popularlyknown as “pasta” or “bazooka,” is prevalent in South America andalso occurs in some parts of the United States. This results in a gray to whiteor dull brown powder, with a slightly sweet smell, that is 40–85% cocaine sulfate.Cocaine hydrochloride is a stable, hydrophilic salt. Thus, it is frequentlysnorted (insufflation) or “tooted” in “lines” or “rails” about one-half to 2 incheslong and one-eighth of an inch thick. Users pour the powdered cocaine onto ahard surface such as a mirror, glass, or slab of marble, and arrange it into lineswith a razor blade, knife, or credit card. One line is snorted into each nostril viaa rolled bill, straw, miniature coke spoon, or a specially grown fingernail. A singlegram of cocaine produces about 30 lines averaging 10–35 mg of powder. Theactual amount of cocaine hydrochloride present in each line depends on thepurity of the drug. Absorption through the nasal mucosa is relatively modestdue to a small surface area and the fact that cocaine is vasoconstrictive.The bioavailability of intranasal cocaine is about 60%. Peak plasma levelsoccur over a range of 30–120 minutes (Barnett, Hawks, & Resnick, 1981).Cocaine is a topical anesthetic and causes numbness of the nose during snorting.Nasal congestion, with stuffiness and sneezing, may occur after snortingcocaine due to both vasoconstrictive properties and contaminants in the preparation.Users may flush out the inside of the nose with a saltwater mixture aftera round of snorting, and they commonly employ decongestants and antihistaminesto relieve symptoms.Cocaine can also be injected intravenously: “shooting” or “mainlining.”The cocaine hydrochloride is mixed with water in a spoon or bottle cap to forma solution. Unlike heroin, cocaine hydrochloride may not need to be heated toenter solution. “Kicking” or “booting” refers to drawing blood from the veinback into the syringe and reinjecting it with each cocaine mixture. Injectiondrug users feel that this produces a heightened drug sensation or “rush,” despitethe lack of a pharmokinetic basis. Following intravenous administration, usersachieve peak plasma levels almost instantaneously.Freebase cocaine is obtained by extracting cocaine hydrochloride with analkali, such as buffered ammonia, then mixing it with a solvent, which is usuallyether. The solvent fraction is separated and volatilized, leaving very smallamounts of residual freebase material. Cocaine freebase is most often smoked ina special freebase glass pipe with a small bowl, into which the freebase cocaineis placed, or in a water pipe with a fine stainless steel screen on which thecocaine is vaporized. Cigarettes are rarely used, because only a small amount ofcigarette smoke actually enters the lungs, wasting valuable cocaine. Cocainehydrochloride is soluble in water and has a melting point of 195°C. In contrast,cocaine freebase is lipid-soluble and has a vaporizing point of 98°C. Thus,cocaine freebase vapors can be smoked, readily crossing the blood–lung barrier