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Unlike general inotropes, these agents exhibit a higher level of specificity as they selectively target the myocardium. They can be categorised into four distinct groups based on their unique mechanisms of action: cardiac glycosides , beta-adrenergic agonists , phosphodiesterase III inhibitors , and calcium sensitizers.
Several β-blockers are specifically indicated for CHF including: bisoprolol, carvedilol, nebivolol and extended-release metoprolol. The antagonism of β 1 inotropic and chronotropic effects decreases the amount of work the heart must perform. It is also thought that catecholamines and other sympathomimetics have an effect on cardiac remodeling ...
Although both vasopressors, vasopressin and epinephrine differ in that vasopressin does not have direct effects on cardiac contractility as epinephrine does. [18] Thus, vasopressin is theorized to be of increased benefit over epinephrine in cardiac arrest due to its properties of not increasing myocardial and cerebral oxygen demands. [18]
This is different from inotropes which increase the force of cardiac contraction. Some substances do both (e.g. dopamine , dobutamine ). If low blood pressure is due to blood loss, then preparations increasing volume of blood circulation—plasma-substituting solutions such as colloid and crystalloid solutions (salt solutions) [ 1 ] —will ...
Both positive and negative inotropes are used in the management of various cardiovascular conditions. The choice of agent depends largely on specific pharmacological effects of individual agents with respect to the condition. One of the most important factors affecting inotropic state is the level of calcium in the cytoplasm of the muscle cell ...
The "vaptan" drugs act by directly blocking the action of vasopressin at its receptors (V 1A, V 1B and V 2).These receptors have a variety of functions, with the V 1A and V 2 receptors are expressed peripherally and involved in the modulation of blood pressure and kidney function respectively, while the V 1A and V 1B receptors are expressed in the central nervous system.
Vasopressin is released into the brain in a circadian rhythm by neurons of the suprachiasmatic nucleus. [21] Vasopressin released from posterior pituitary is associated with nausea. [22] Recent evidence suggests that vasopressin may have analgesic effects. The analgesia effects of vasopressin were found to be dependent on both stress and sex. [23]
Commonly used vasopressors include catecholamine (e.g., dopamine, norepinephrine, epinephrine) and non-catecholamine (e.g., vasopressin). but these agents are not always effective in reversing vasodilatory shock, and their use can be associated with significant side effects including limb ischemia and cardiac arrhythmia. Angiotensin II is as a ...