Emergency Meds: Antidysrhythmics & Beta Blocker Differences

SimpleNursing Editorial Team Aug 27, 2018
Nurse holds a prescription bottle containing medication tablets. The nurse is wearing scrubs and a stethoscope.

As nursing students, it’s crucial to grasp the fundamental differences between antidysrhythmic drugs and beta blockers to ensure safe and effective client care. 

Antidysrhythmics and beta blockers are essential tools in managing cardiac arrhythmias, but they differ significantly in their mechanisms of action and clinical applications. 

Antidysrhythmic Drugs

Amiodarone is a popular antidysrhythmic medication that has negative chronotropic effects and dromotropic effects. How does this happen?

Antidysrhythmics as a Negative Chronotropic

Antidysrhythmics are considered a negative chronotropic because they can effectively reduce the heart rate. By targeting the SA node, antidysrhythmic drugs influence the contraction and conduction of electrical impulses. Since amiodarone is a negative chronotropic drug, its purpose is also to decrease the electrical impulses coming from the AV node.

So, when a client is experiencing a detrimental rhythm, like ventricular fibrillation, the priority is to get them out of that state by providing chemical cardioversion in the form of Amiodarone or antidysrhythmics. After giving Amiodarone, the client will be given subsequent shocks using a defibrillator to restore the heart’s normal rhythm.

The main goal of antidysrhythmics is to decrease the heart rate because when a client has an irregular rhythm, the heart is going so fast.

Antidysrhythmics as a Negative Dromotropic

Since antidysrhythmics are focused on getting the electrical impulses down, they are also considered as negative dromotropic.

On the other hand, antidysrhythmics don’t have inotropic properties.

Beta Blockers

Beta blockers work by blocking the effects of the hormone epinephrine, also known as adrenalinet that blocks the beta from the system. Beta blockers are easily recognized by ending in “-lol.” Some popular generic names are Atenolol and Metoprolol. 

As for some brand names, Lopressor is a widely known brand, as well as Coreg.

Beta blockers block beta receptors of the heart and lungs. To remember which beta blocker is given to the heart and lungs, you just have to remember that beta 1 refers to the heart because there’s only one heart; while beta 2 is given to the lungs because there are two lungs.

Beta Blockers Nursing Considerations

A typical side effect when giving beta blockers to clients is that, aside from being anti-hypertensive drugs, they are also anti-rate drugs. This means that beta blockers are non-specific that even if the intention to give the drug is to block the increased heart rate, the agonists used for breathing are also blocked. Therefore, the client is expected to have decreased respiration.

Beta Blocker as a Negative Chronotropic

Since beta blockers decrease the heart rate, it’s considered a negative chronotropic drug because of the primary goal of decreasing the heart rate.

Beta Blocker as a Negative Dromotropic

On the other hand, beta blockers are also considered a negative dromotropic because they block electrical conductivity inside the heart, signaling to slow down and stabilize the electrical impulses. As a result, steadying the rhythm. This is similar to telling the SA and AV nodes to calm down.

Beta Blockers & Antidysrhythmic Drugs Mechanism of Action 

Antidysrhythmics and beta blockers are different regarding the mechanism of action in bringing down the excitability of the electrical impulses which results in bringing down the heart rate.

There is a big difference between these two drugs, but their goal is similar.

Antidysrhythmics affect the SA and AV node directly, while beta blockers affect the beta receptors.

MoA of Amiodarone

Amiodarone, an example of an antidysrhythmic medication, exhibits its therapeutic effects through multiple mechanisms. This drug predominantly works by blocking multiple ion channels, including potassium, sodium, and calcium channels in cardiac cells. By doing so, it prolongs the action potential duration and refractory period, effectively reducing the excitability of cardiac tissue.

Furthermore, amiodarone also possesses beta-blocking properties, contributing to its overall antiarrhythmic effects. By inhibiting beta receptors, it decreases sympathetic stimulation, reducing heart rate and contractility. This dual action makes amiodarone a versatile medication for managing various dysrhythmias.

Understand Effective Client Care

In the fast-paced world of health care, nursing students must acquire a solid understanding of cardiac pharmacology to make critical decisions about client care. When it comes to managing arrhythmias, two classes of medications, antidysrhythmics, and beta blockers, play vital roles. 

To enhance your knowledge of cardiac pharmacology and gain a comprehensive understanding of various medications used in arrhythmia management, consider SimpleNursing as your supplemental study resource.

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