78: Cocaine

HISTORY AND EPIDEMIOLOGY

Cocaine is contained in the leaves of Erythroxylum coca, a shrub that grows abundantly in Colombia, Peru, Bolivia, the West Indies, and Indonesia. As early as the 6th century, the inhabitants of Peru chewed or sucked on the leaves for social and religious reasons. In the 1100s, the Incas used cocaine-filled saliva as local anesthesia for ritual trephinations of the skull.⁶⁸

In 1859, Albert Niemann isolated cocaine as the active ingredient of the plant. By 1879, Vassili von Anrep demonstrated that cocaine could numb the tongue.¹⁰⁸ However, Europeans knew little about cocaine until 1884, when the Austrian ophthalmologist Karl Koller introduced cocaine as an effective local anesthetic for eye surgery and Koller’s colleague, Sigmund Freud, wrote extensively on the psychoactive properties of cocaine.⁵⁵ Following these revelations, Merck, Europe’s main cocaine producer, increased production from less than 0.75 pounds in 1883 to more than 150,000 pounds in 1886.¹⁰⁴

Simultaneously, reports of complications from the therapeutic use of cocaine began to appear. In 1886, a 25 year-old man had a “pulseless” syncope after cocaine was applied to his eye to remove a foreign body.²¹¹ By 1887, more than 30 cases of severe toxicity were reported,¹⁸¹ and by 1895 at least eight fatalities resulting from a variety of doses and routes of administration were summarized in one article.⁵⁷ Recreational cocaine use was legal in the United States until the passage of the Harrison Narcotic Act of 1914, when cocaine was restricted to medical use. Not until 1982, however, was the first cocaine-associated myocardial infarction reported in the United States.²⁸

Currently, cocaine is an approved pharmaceutical. It is used primarily for topical anesthesia of cutaneous lacerations or during otolaryngology procedures as a vasoconstrictor and topical anesthetic. Although multiple factors have fostered a decline in the medicinal use of cocaine,^18,63,130 the recreational use of cocaine remains a significant problem.

The United Nations office on Drugs and Crime estimates that there are 13 to 19 million cocaine users worldwide.³⁴ In the United States, it is estimated that there are 1.5 million cocaine users.⁴³

PHARMACOLOGY

The alkaloid form of cocaine, benzoylmethylecgonine, is a weak base that is relatively insoluble in water. It is extracted from the leaf by mechanical degradation in the presence of a hydrocarbon. The resulting product is converted into a hydrochloride salt to yield a white powder, cocaine hydrochloride, which is very water soluble. Cocaine hydrochloride can be insufflated, applied topically to mucous membranes, dissolved in water and injected, or ingested; however, it degrades rapidly when pyrolyzed. Smokable cocaine (crack) is formed by dissolving cocaine hydrochloride in water and adding a strong base. A hydrocarbon solvent is added, the cocaine base is extracted into the organic phase, and then evaporated. The term “free-base” refers to the ...