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

140 III. SUBSTANCES OF ABUSEgesia in the opioid-free individual but are addicting, and when given to someonewho is opioid dependent produce an abstinence syndrome. The semisyntheticcompound nalbuphine, mentioned earlier, has similar properties.Tramadol (Ultram), a synthetic aminocyclohexanol, binds to mu opioid receptorsand also inhibits reuptake of norepinephrine and serotonin; there havebeen increasing reports of tramadol abuse.Despite their similarities, opioids may have varying effects on opioid receptors.For example, the mu receptor is occupied preferentially by the classicmorphine-like opioids, but butorphanol (Stadol) and nalbuphaine (Nubain)prefer the kappa receptor. Both receptors are highly specific, and an abstinencesyndrome mediated by the kappa receptor will not be relieved if a mu receptorcompound is administered. Like pentazocine, butorphanol, and tramadol,buprenorphine (Subutex) is a mixed opiate agonist–antagonist, with partial mureceptor agonism and full kappa agonism. Partial agonists show a “ceilingeffect”; unlike full agonists, dose escalation does not produce ever-increasingpharmacological effects. There are also compounds that bind selectively to thereceptor site, yet produce no agonistic action. These compounds are antagonisticin nature, because they occupy the receptor site and exclude agonist opioids;examples include naloxone (Narcan) and naltrexone (ReVia). These opioidantagonists, useful for the treatment of opioid intoxication and addiction, arediscussed later. Relative to full agonists, partial agonists may act as antagonists.Also of interest is the discovery and description of endogenous opioid substancesin humans, operating at the kappa receptor site along the spectrum fromagonistic to antagonistic function. To date, no endogenous mu receptor opioidhas been discovered (Jaffe, 1989).DIAGNOSISIn the framework provided by the fourth edition of the Diagnostic and StatisticalManual of Mental Disorders (DSM-IV-TR; American Psychiatric Association,2000), the problem of opioid misuse is divided into four categories, amongwhich there may be some overlap. Opioid intoxication and opioid withdrawalare specifically defined in DSM-IV-TR. Facility in making these diagnosesrequires a clear understanding of the clinical features associated with opioids, asdiscussed later in this chapter. In addition to intoxication or withdrawal, it isimportant to characterize the individual’s relationship to the use of opioids overtime.Initial assessment always includes a thorough history of the individual’ssubstance use over time, with corroboration from outside sources if possible.This corroboration of the individual’s history is essential because of the nearlyuniversal presence of denial in the nonrecovered substance abuser. Minimizationof the frequency and amounts of opioid use is common, as is the illu-