ABSTRACT
In 2007, 1.1 million Americans aged 12 and older had abused methamphetamine at least once in the month prior to being surveyed (1), which included 3.3% of persons aged 12-13, 8.9% of persons aged 14-15, 16.0% of ages 16-17, with a peak of 21.6% at age 18-20 (2). Of those who used methamphetamine for the first time in 2006, the mean age at first use was 22.2 years, which is up considerably from the mean age of 18.6 in 2005. According to the 2007 NSDUH, however, the estimated number of methamphetamine users declined from 1.9 million in 2006 to 1.3 million in 2007 (1).a
The homeostatic regulation of central and peripheral autonomic function is mediated principally through the actions of the sympathetic nervous system (SNS) and moderated through the opposing effects of the parasympathetic nervous system (PNS). Stimulation of the SNS normally occurs in response to physical activity, psychological stress, generalized allergic reactions, and situations that require a heightened response. As a result, the physiological reaction of the SNS favors functions that support vigorous physical activity and response to stressors; thus, the SNS is labeled as the “fight-or-flight” response. Increases or enhancement of cardiac contraction, vasomotor tone, blood pressure, bronchial airway tone, carbohydrate and fatty acid metabolism, psychomotor activity, mood, and behavior are physiological responses that occur following SNS stimulation. The variety of agents listed in Table 15.1 pharmacologicallymimic or alter sympathetic activity. These substances were originally classified as catecholamines for their structural resemblance to OH-substituted o-dihydroxybenzene (catechol). Although most are clinically useful, toxicity of these compounds results from development of the adverse reactions, from abuse or overuse, and is manifested as an exaggeration of the pharmacological profiles.
