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Beta-2 adrenergic receptors play a central role in the management of bronchospastic disorders and are among the most frequently targeted pathways in respiratory and cardiovascular care. This activity examines the molecular mechanisms of β2 receptor signaling and compares short-, long-, and ultra-long-acting agonists, as well as nonselective and cardioselective antagonists. This activity also reviews the indications, routes of administration, and evidence-based dosing strategies. Additionally, this activity identifies key adverse effects of β2 agonists and antagonists, and implements monitoring protocols for serum electrolytes, heart rate, and pulmonary function to ensure patient safety. Furthermore, this activity also covers the management of toxicity, including recognition of overdose symptoms and the appropriate use of beta-blocker antidotes when indicated. This activity also emphasizes the importance of interprofessional collaboration among healthcare providers: pharmacists can focus on medication reconciliation and screening for potential drug interactions; nurses can gain expertise in inhaler education and monitoring vital signs; and physicians will be guided in applying guideline-driven therapy selection and managing acute exacerbations, particularly in patients with asthma and COPD. Objectives: Identify the pharmacological mechanisms, receptor subtypes, and physiological effects of β2 adrenergic agonists and antagonists. Implement evidence-based dosing regimens and appropriate routes of administration for β2-targeted medications. Select the most appropriate β2 agonist or antagonist based on patient-specific factors, disease severity, and guideline recommendations. Collaborate with interprofessional healthcare providers to ensure safe and effective therapy and manage acute exacerbations and adjustment of treatment for patients with comorbid conditions. Access free multiple choice questions on this topic.

β2 Agonist toxicity may occur both accidentally and intentionally. The most serious life-threatening complication is severe hypokalemia resulting from the intracellular shift of potassium, which predisposes patients to cardiac arrhythmias.[60] In addition, toxicity may also manifest as exaggerated forms of known adverse effects, including hypotension with a bounding pulse (predominantly affecting diastolic pressure), supraventricular tachycardia or ventricular extrasystoles, tremors, hyperglycemia, lactic acidosis, tachypnea, and pupillary dilation.[61][62] In cases of β2 agonist overdose, β-blockers such as propranolol and esmolol may be used as antidotes through competitive antagonism at β2 receptors.[63] Toxic doses of β-blockers can exacerbate asthma and lead to serious complications, including bradycardia, prolonged QRS complexes, hypotension, arrhythmias, hypoglycemia, hypothermia, severe peripheral arterial disease, high-grade sinoatrial or atrioventricular block, and variant angina.[64][65][66]

Asthma and COPD are highly prevalent chronic respiratory conditions that significantly impact patients' quality of life worldwide. Although treatment guidelines vary across regions, β2 adrenergic agonists consistently remain a cornerstone of both acute and chronic management due to their potent bronchodilatory effects. Their ubiquitous role in therapy underscores the importance of clinicians maintaining a thorough and up-to-date understanding of their pharmacological properties, including mechanisms of action, potential adverse effects, contraindications, and concerns related to tolerance. Individual responses to β2 agonists can vary considerably due to factors such as genetic polymorphisms and underlying inflammation. Improper use or overuse of these agents may lead to rapid tolerance, diminishing their bronchodilator effectiveness during critical exacerbations.[67] As β2 agonists are often prescribed as part of inhaled β2 agonist–corticosteroid combinations for first-line asthma maintenance therapy, patients must receive thorough education on proper inhaler technique, dosing, and timing to maximize efficacy and minimize the risk of adverse events. The optimal care of patients with chronic respiratory inflammatory diseases requires a coordinated, interprofessional approach. Pulmonologists, allergists, primary care physicians, pharmacists, and nurses must work collaboratively to select and customize therapies, tailoring treatment regimens to individual patient-specific factors and disease severity. This includes tailoring treatment regimens, monitoring efficacy and safety, regularly evaluating lung function, and assessing for adverse effects such as cardiovascular complications. Effective communication among healthcare team members is essential to ensure timely updates on patient status and appropriate adjustments to treatment plans. As β2 agonists may exert systemic effects, such as influencing heart rate and interacting with other medications, clinicians in related specialties, including cardiology and obstetrics, must also remain informed about the use of these drugs. In certain cases, adjustments in management may be necessary to prevent exacerbation of comorbid conditions or triggering adverse drug interactions.

As β2 agonists may exert systemic effects, such as influencing heart rate and interacting with other medications, clinicians in related specialties, including cardiology and obstetrics, must also remain informed about the use of these drugs. In certain cases, adjustments in management may be necessary to prevent exacerbation of comorbid conditions or triggering adverse drug interactions. Finally, public education is crucial. Patients and caregivers should be informed of the risks associated with inappropriate or unsupervised use of β2 agonists (eg, misuse for presumed anabolic purposes). Concurrently, emergency physicians and nurses require specific training to recognize and manage β2 agonist overdose, ensuring timely and effective intervention.