Chapter 18: Substance Use Disorders & Dependence

Substance Use Disorders & Dependence pharmacology chapter explores the clinical management and significance of substance use disorder (SUD) within Canadian healthcare, focusing on five major classes of psychoactive substances: opioids, central nervous system (CNS) stimulants, CNS depressants, alcohol, and nicotine. The discussion defines key concepts such as addiction, physical and psychological dependence, intoxication, habituation, and withdrawal, emphasizing that SUD is a complex, chronic disorder. The chapter contrasts the physiological effects, symptoms of intoxication, and unique withdrawal manifestations for each substance class, noting that acute opioid withdrawal presents with signs like piloerection, mydriasis, and elevated pulse, while stimulant withdrawal often involves psychomotor retardation and suicidal ideation. Critical pharmaceutical treatments are detailed, including methadone or clonidine substitution for opioid withdrawal, and the use of the antagonist naltrexone to prevent opioid and alcohol relapse by blocking euphoria. For life-threatening ethanol (alcohol) withdrawal, characterized by delirium tremens, benzodiazepines are the required treatment, often guided by assessment tools like CIWA-Ar. Stimulant withdrawal treatment, conversely, is primarily supportive, as there are no specific pharmacological treatments to reverse acute toxicity. Furthermore, the text addresses the serious public health concerns associated with specific drugs like fentanyl and methamphetamine, the dangers of depressants like flunitrazepam ("roofies") used as a date rape drug, and the neurodevelopmental risks of cannabis use in adolescents. Finally, the nursing process is highlighted as essential, stressing the need for nonjudgemental care, the use of screening tools like CAGE-AID, and the prioritization of patient safety, especially when managing complications like seizures or respiratory depression during detox.