85: Nicotine

HISTORY AND EPIDEMIOLOGY

The tobacco plant is native to the Americas, and its use most likely predates the Mayan empire. In 1492 Christopher Columbus and his crew were given tobacco by the Arawaks, but reportedly threw it away not knowing any use for it. Ramon Pane, a monk who accompanied Columbus on his second voyage to America, is credited with introducing tobacco to Europe.⁸³

The principal alkaloid, nicotine, is still primarily derived from members of the genus Nicotiana, collectively known as the tobacco plant, in the family Solanaceae. The most important species in human use today is Nicotiana tabacum and the primary method of nicotine exposure is cigarette smoking. Because of the highly addictive properties of nicotine, the global disease burden related to cigarette use is staggering. Cigarette smoking increases rates of chronic obstructive pulmonary disease (COPD), cardiovascular disease, pulmonary infections, macular degeneration, and cancers, and causes more than 5 million deaths worldwide per year. Chronic nicotine exposure causes cardiovascular damage related to catecholamine release and vasoconstriction, and directly promotes angiogenesis, neuroteratogenicity, and possibly some cancers.⁵¹ However, there are more than 3000 components to tobacco smoke and nicotine per se may not be the crucial determinant of the total health burden associated with its use.

Although the long-term effects of cigarette smoking and tobacco dependency are significant, this chapter is concerned with the sources, effects, and management of acute toxicity referable to nicotinic receptor stimulation and cholinergic activation. Reviews of case data from the National Poison Data System suggest that cigarettes are by far the most common vehicle implicated in acute nicotine exposures and poisoning in the United States.² Smoking cessation products containing nicotine are increasingly available and some of the more novel smokeless tobacco products have the appearance of candy, raising concern about the potential for unintentional poisoning of young children, in particular.²¹

Compared with other xenobiotics, exposure to nicotine containing products is nonetheless a relatively rare cause of acute poisoning. For example, over a period of 27 years from 1983 to 2009, tobacco products accounted for 217,340 calls, or 0.37%, of all pediatric exposures reported to poison centers in the United States,² and accounted for 0.7% of all unintentional poisoning cases in children treated in US hospital emergency departments in one national estimate.³¹ Although fatalities are reported, most patients with nicotine exposure have a benign course, with only mild to moderate symptoms and an infrequent need for hospitalization.

Nicotine receptor partial agonists/antagonists are a relatively new class of drug mimicking the physiologic effects of nicotine. A 2-year review of poison center data from the California Poison Control System found 36 calls regarding human exposures to varenicline (Chantix), which was approved in 2006 by the US Food and Drug Administration (FDA) as a smoking cessation aid.⁴⁶ Of these, 17 cases had no outcome data or involved coingestions. ...