Esmolol, sold under the brand name Brevibloc, is a cardio selective beta1 receptor blocker with rapid onset, a very short duration of action, and no significant intrinsic sympathomimetic or membrane stabilising activity at therapeutic dosages. It is a class II antiarrhythmic. Esmolol decreases the force and rate of heart contractions by blocking beta-adrenergic receptors of the sympathetic nervous system, which are found in the heart and other organs of the body. Esmolol prevents the action of two naturally occurring substances: epinephrine and norepinephrine.It was patented in 1980 and approved for medical use in 1987. Medical uses
To terminate supraventricular tachycardia,
Episodic atrial fibrillation or flutter,
Arrhythmia during anaesthesia,
To reduce HR and BP during and after cardiac surgery, and
In early treatment of myocardial infarction. Esmolol is also used in blunting the hemodynamic response to laryngoscopy and intubation. Dosing
A loading dose of 0.5 mg/kg is given followed
by 0.05–0.2 mg/kg/min infusion. Metabolism
Esmolol is considered a soft drug, one that is rapidly metabolized to an inactive form. Esmolol is rapidly metabolized by hydrolysis of the ester linkage, chiefly by the esterases in the cytosol of red blood cells and not by plasma cholinesterases or red cell membrane acetylcholinesterase. Total body clearance in man was found to be about 20 L/kg/hr, which is greater than cardiac output; thus the metabolism of esmolol is not limited by the rate of blood flow to metabolizing tissues such as the liver or affected by hepatic or renal blood flow. Esmolols short duration of action is based on the ester-methyl side chain which allows for quick hydrolysis.
Treatment
Anumonye reported treatment success with lorazepam; others found benefit with antidepressants and relaxation exercises. Epidemiology
BFS has been reported in other African cultures, and also in Brazil, Argentina, and Ethiopian Jews. Historic higher reported prevalence among males may be due to more males being present in higher education in African countries. Studies since the 1990s have not verified gender differences. Other studies found a possible association with low socioeconomic status, an association with average or higher intelligence, and a high association with neuroticism. Individuals with BFS have been found to have problems with isolation, poor study habits, and the use of psychostimulants as well as physical changes including in muscle tension and heart rate. History
The condition was first described by R. H. Prince who named the condition based on the term brain fag used by students who believed their symptoms were attributed to "brain fatigue". However, this term was used in the United States and Europe dating back to 1839. Furthermore, in a detailed historical account, Ayonrinde (2020) illustrates that contrary to widely held and published belief in diagnostic manuals, psychiatric, social science and educational text, the term "Brain Fag" and associated syndromes of anxiety, affective and somatoform symptoms in student and "brain worker" populations were first described in nineteenth century Britain (Tunstall, 1850) with dissemination across the British Empire. Ayonrinde concludes that, the time has come for the decolonization of brain fag and its African syndromization in the true spirit of ethical scientific rigor in the twenty-first century. See also
Burnout
Exhaustion


== References ==