6.14:
Adrenergic Antagonists: Pharmacological Actions of β-Receptor Blockers
β-receptor blockers predominantly exhibit cardiovascular effects by inhibiting catecholamine-induced sympathetic responses. They decrease heart rate, contractility, and cardiac output leading to cardiac depression.
This can potentially result in life-threatening bradycardia and heart failure.
Therapeutically, β-blockers are utilized as mild antihypertensives, and for treating angina pectoris and cardiac arrhythmias.
Nonselective β-blockers inhibit the β2-receptors in bronchial smooth muscle, causing bronchoconstriction. This can be potentially fatal to patients with asthma or obstructive lung diseases.
They help control exaggerated sympathetic responses in pheochromocytoma and thyrotoxicosis. They are useful in chronic migraine prevention and act as an anti-anxiety agent.
Further, β-blockers like propranolol impede sympathetically induced lipolysis and insulin release.
They also treat chronic open-angle glaucoma by reducing aqueous humor production to lower intraocular pressure.
Additionally, propranolol is the drug of choice for treating severe infantile hemangioma.
β-blocker treatment can also lead to CNS-related effects like fatigue, forgetfulness, sleep disturbances and depression.
6.14:
Adrenergic Antagonists: Pharmacological Actions of β-Receptor Blockers
β-receptor blockers significantly impact the cardiovascular system by counteracting catecholamine-induced sympathetic responses. These medications decrease heart rate, contractility, and cardiac output, potentially leading to cardiac depression, life-threatening bradycardia, and death. Therapeutically, β-blockers function as mild antihypertensives and are utilized in treating angina pectoris and cardiac arrhythmias. However, nonselective β-blockers inhibit β2-receptors in bronchial smooth muscle, resulting in bronchoconstriction, which can be detrimental to patients with asthma or obstructive lung diseases.
In addition to cardiovascular benefits, β-blockers manage exaggerated sympathetic responses in conditions such as pheochromocytoma and thyrotoxicosis. They also play a role in chronic migraine prevention, exhibit anti-anxiety properties, and hinder sympathetically induced lipolysis and insulin release, as demonstrated by propranolol. Propranolol, in particular, is highly effective in treating severe infantile hemangioma. Furthermore, these drugs treat chronic open-angle glaucoma by decreasing aqueous humor production, ultimately reducing intraocular pressure. However, it is essential to note that β-blocker treatment can cause CNS-related side effects, including fatigue, forgetfulness, sleep disturbances, and depression. Overall, β-blockers offer a wide range of therapeutic applications, but it is crucial to consider their potential side effects and contraindications when determining the most suitable treatment option.