Alpha-and Beta-Adrenoceptor Antagonists

Preoperative metoprolol improves cardiovascular stability and reduces oxygen consumption after thoracotomy

“…In the presence of high plasma catecholamine levels, blockade of P2-receptors may increase afterload as the altered balance between a-and p2-receptors in peripheral vessels may lead to vasoconstriction (29). Combined a-and P-blockade may result in peripheral vasodilation, especially in combination with anaesthetics, and can cause severe haemodynamic side effects (22,30). We therefore preferred a selective P1-antagonist and, due to the oral medication, we selected metoprolol which has some lipid solubility and a relatively high bioavailability.…”

Effect of Low Dose Propranonol on Perioperative Stress Induced Hemodynamic Changes in Upper Abdominal Surgery

“…It has been demonstrated that beta-adrenoceptor blocker, in low therapeutic doses, causes only modest reduction in cardiac output while decreasing the incidence of arrhythmia and myocardial ischaemia after laryngoscope and intubations 14,15 . Even a single dose of beta-blocker given as premedications decreases the incidence of myocardial ischaemia 5 . Propranolol has been shown to exert a alleviating effect in anxiety in addition to beta-blockade.…”

“…Increased hypothalamic activity induced by nociceptive stimulation is accompanied by an increased traffic in sympathetic efferent tracts resulting in adrenergic response [2][3][4] . Thus it has been proposed that an abrupt increase in circulating catecholemines may be associated with potentially severe hypertension, tachycardia, which in turn may cause cardiac arrhythmias, myocardial ischemia, left ventricular dysfunction and rupture of cerebral aneurysm 5,6 in susceptible individuals 7,8 .…”