Chapter 33: Anticholinergic Agents

Although this class of drugs is used less frequently today due to the development of more targeted therapies, atropine remains the classic prototype, utilized widely across several conditions. Therapeutic indications are extensive and include depressing salivation and bronchial secretions, inhibiting vagal responses in the heart to restore cardiac rate, treating certain types of parkinsonism, relaxing hyperactive GI tracts and ureteral spasms, managing peptic ulcers, and achieving ophthalmic effects such as mydriasis (pupil dilation) and cycloplegia (blurring of near vision). Specific drugs like ipratropium are tailored for respiratory issues, while others such as oxybutynin and solifenacin target the urinary tract to treat overactive bladder symptoms. Pharmacokinetic profiles show that these drugs are generally well absorbed after administration, distributed throughout the body—often crossing the blood–brain barrier—and excreted in the urine. Because the adverse reactions stem directly from systemic cholinergic blockade, they are dose-dependent and include significant effects such as blurred vision, dry mouth, altered taste perception, constipation, urinary hesitancy and retention, tachycardia, CNS effects like confusion and excitement, and a critical risk of heat prostration due to decreased sweating. Anticholinergic agents are contraindicated in patients with conditions like glaucoma, stenosing peptic ulcer, intestinal obstruction (such as paralytic ileus), prostatic hypertrophy, and specific cardiac arrhythmias, as these conditions would be exacerbated by parasympathetic blocking. When managing toxicity, which can occur inadvertently from products like the belladonna plant, symptoms escalate from dry mouth to delirium and coma, necessitating prompt intervention, often involving gastric lavage and the use of physostigmine as an antidote. Nursing care emphasizes monitoring for cardiovascular and CNS changes, implementing safety precautions for vision and dizziness, and educating patients, particularly vulnerable populations like children and older adults, on maintaining hydration, avoiding heat exposure, and dealing with common effects like dry mouth and constipation.