From the Guidelines
No, beta blockers do not lower the amount of adrenaline (epinephrine) released by the adrenal glands, but instead, they block the effects of adrenaline on beta-adrenergic receptors. Beta blockers work by inhibiting the adverse effects of the sympathetic nervous system, which can increase ventricular volumes and pressure, impair sodium excretion, and induce cardiac hypertrophy, among other deleterious effects 1. The primary mechanism of beta blockers is to block the binding of adrenaline to beta-adrenergic receptors in the heart and blood vessels, resulting in a slower heart rate, lower blood pressure, and reduced physical symptoms of anxiety.
Some key points to consider when using beta blockers include:
- They do not reduce the production of adrenaline by the adrenal glands, but rather mitigate its effects on the body 1
- They are effective in reducing the risk of death in patients with chronic heart failure, with three beta blockers (bisoprolol, sustained-release metoprolol, and carvedilol) shown to be particularly effective 1
- The choice of beta blocker may depend on the specific condition being treated, as well as the individual patient's response to the medication
- Beta blockers are commonly used to manage conditions such as hypertension, angina, certain arrhythmias, and situational anxiety, by blocking the effects of adrenaline on the heart and blood vessels 1
It is essential to note that beta blockers do not address the underlying cause of increased adrenaline production, but rather block its effects on certain organs and tissues, which can be beneficial in managing various medical conditions 1.
From the Research
Beta Blockers and Adrenaline Release
- Beta blockers are known to act by antagonizing the actions of the endogenous adrenergic agonists epinephrine and norepinephrine at the beta-adrenergic receptors 2
- They do not directly lower the amount of adrenaline released by the adrenal glands, but rather block the effects of adrenaline on the body 2, 3
- Beta blockers can be classified into different types, including nonselective beta blockers, cardioselective beta blockers, and vasodilating beta blockers, each with different mechanisms of action 3
Mechanism of Action
- Beta blockers work by competing with catecholamines at beta-adrenoreceptors, reducing oxygen demand by exerting a negative inotropic and chronotropic effect 4
- They also reduce blood pressure and possess antiarrhythmic effects, and can penetrate the central nervous system to different degrees, causing a wide variety of CNS adverse effects 4
- Nonselective beta blockers can prevent beta 2-mediated bronchodilation, thereby exacerbating bronchospastic disease in some patients 4
Effects on Adrenaline
- Beta blockers do not reduce the release of adrenaline from the adrenal glands, but rather block the effects of adrenaline on the body 2, 3
- The use of beta blockers can lead to a decrease in the sympathetic tone, which can result in a decrease in the release of adrenaline, but this is an indirect effect 5