Chapter 20: Anxiolytic & Hypnotic Agents

Anxiolytic & Hypnotic Agents drugs are defined based on their primary function: anxiolytics reduce or prevent feelings of tension, nervousness, or fear (anxiety); sedatives calm patients and reduce awareness of the environment (sedation); and hypnotics cause further CNS depression to induce sleep (hypnosis). Benzodiazepines represent the most frequently prescribed class of anxiolytics because they achieve anxiolytic effects at doses significantly lower than those needed for sedation. Their mechanism involves acting in the limbic system and the reticular activating system (RAS) to enhance the effects of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter, thereby interfering with neuron firing. Indications for benzodiazepines include managing anxiety disorders, treating alcohol withdrawal, and providing preoperative relief. A critical nursing concern is the black box warning emphasizing that co-administration with opioids can lead to profound sedation, respiratory depression, coma, or death. Furthermore, nurses must be aware that approximately 15% to 20% of African-Americans exhibit delayed benzodiazepine metabolism, requiring lower initial doses to mitigate increased risk of sedation and adverse effects. Barbiturates, an older class of CNS depressants, are generally less desirable due to greater risks of addiction, dependence, and more severe adverse effects compared to newer agents. Barbiturates induce liver enzyme systems, which rapidly metabolize and reduce the effectiveness of many concurrently administered drugs, including oral anticoagulants, corticosteroids, and oral contraceptives. The chapter also covers several other agents, such as ramelteon and tasimelteon, which are melatonin receptor agonists; suvorexant, an orexin receptor antagonist that suppresses the wake drive; and buspirone, a non-sedating anxiolytic. Newer hypnotics like zolpidem and eszopiclone are associated with complex behaviors, including "sleep driving," requiring patients to plan for at least 7 hours in bed after dosing. Nursing considerations across all drug classes emphasize reducing dosages for older adults who are highly susceptible to CNS effects like dizziness and hallucinations, and using caution in children due to unpredictable responses. Nurses must also monitor hepatic and renal function, provide thorough patient teaching (including avoiding abrupt cessation to prevent withdrawal syndrome), and strictly avoid intra-arterial administration of parenteral forms due to the high risk of severe arteriospasm and gangrene.