Adrenaline blocker
Pro Research Analysisby 
Searched over 200M research papers for "adrenaline blocker"
Consensus Meter
Adrenaline Blockers: Mechanisms and Effects
Introduction to Adrenaline Blockers
Adrenaline blockers, also known as adrenergic blockers, are medications that inhibit the effects of adrenaline (epinephrine) on the body. These blockers are categorized into alpha-blockers and beta-blockers, each targeting different adrenergic receptors. Understanding their mechanisms and effects is crucial for their application in various medical conditions.
Mechanisms of Alpha- and Beta-Blockers
Alpha-Blockers and Their Effects
Alpha-blockers, such as phentolamine and piperoxan, primarily inhibit the alpha-adrenergic receptors. These receptors are involved in vasoconstriction and other sympathetic nervous system activities. Phentolamine has been shown to reduce the bradykinin-induced relaxation in guinea-pig ileum and does not prevent the increase in platelet adhesiveness induced by adrenaline . Additionally, phentolamine can normalize adrenaline-induced blood glucose elevation by diminishing liver glycogenolysis via alpha receptors, which could be beneficial in managing stress-induced metabolic deviations in diabetics.
Beta-Blockers and Their Effects
Beta-blockers, such as propranolol, atenolol, and sotalol, inhibit beta-adrenergic receptors, which are involved in heart rate regulation, vasodilation, and metabolic processes. Propranolol and pronethalol have been found to block the rise in clotting factor VIII induced by adrenaline, indicating that this effect is mediated by beta-receptors. Propranolol also partially blocks adrenaline-induced relaxation in guinea-pig ileum, while sotalol almost completely blocks it. Furthermore, beta-blockers like propranolol and atenolol can prevent adrenaline-induced changes in heart rate, blood pressure, and electrocardiographic parameters, which are crucial in managing conditions like myocardial infarction.
Comparative Effects of Selective and Non-Selective Beta-Blockers
Hemodynamic and Metabolic Responses
Selective beta-1 blockers (e.g., atenolol) and non-selective beta-blockers (e.g., propranolol) have different impacts on hemodynamic and metabolic responses to adrenaline. Atenolol partly prevents the rise in systolic blood pressure and changes in heart rate induced by adrenaline, while propranolol and the beta-2 selective blocker ICI 118551 are more effective in blocking electrocardiographic and metabolic effects. Non-selective beta-blockers like propranolol cause a marked pressor effect and a significant fall in heart rate during adrenaline infusion, whereas selective beta-1 blockers like metoprolol result in a slight rise in blood pressure and an increase in heart rate.
Combined Alpha and Beta Blockade
Labetalol, a combined alpha and beta blocker, effectively prevents the hemodynamic, electrocardiographic, and hypokalaemic effects of increased circulating adrenaline. This dual blockade is necessary to control both metabolic and circulatory responses during heightened sympathoadrenal activity, making labetalol a valuable option in such scenarios.
Clinical Applications and Safety
Use in Surgical Procedures
Adrenaline combined with lidocaine is used in digital nerve blocks to prolong anesthesia and reduce bleeding during surgery. Although traditionally avoided in areas with end arteries due to concerns about ischemia, recent studies suggest that the combination can be safe and effective, providing extended postoperative pain relief and a bloodless operating field.
Managing Hemorrhage in Veterinary Medicine
In veterinary applications, adrenaline in a bilateral maxillary nerve block significantly reduces intraoperative hemorrhage during procedures like staphylectomy in dogs, without notable adverse effects. This highlights the potential clinical advantages of adrenaline in improving surgical outcomes and reducing blood loss.
Conclusion
Adrenaline blockers, both alpha and beta, play a crucial role in managing the physiological effects of adrenaline. Their application ranges from controlling hemodynamic and metabolic responses to improving surgical outcomes. Understanding the specific mechanisms and effects of these blockers allows for their effective and safe use in various medical and veterinary contexts.
Sources and full results
Most relevant research papers on this topic