One of the most common medication classes you’ll see in the clinical setting is the beta blocker. In this post we’ll talk about what they are, how they work, what conditions they’re used for and how you’re going to monitor your patient. Show
What are Beta Blockers?Beta blockers are medications that have beta-adrenergic blocking properties, meaning they block sympathetic nervous system activity. They are mainly used to treat hypertension, but you will see a few other uses as well. Don’t worry, we’ll talk about these further on. Where do Beta Blockers work?The first thing to understand here is that there are two types of beta receptors in the body. Beta-1 receptors, which are present in the heart, and beta-2 receptors, which are present in vascular smooth muscle and the muscle lining the airways. Since beta-1 receptors are only present in the heart, when a drug is specific to beta-1 receptors it is often called “cardioselective.” Other beta blockers target both beta-1 and beta-2 receptors, so you may hear these referred to as “non-selective” as their effects are more widespread, with greater side effects as well. What do Beta Blockers do?Beta-1 adrenergic blockers, such as atenolol and metoprolol, exert their influence on the receptors located in the heart. By blocking sympathetic activity at the receptor site, they slow the heart rate and decrease contractile force, lowering the patient’s blood pressure. Beta blockers also cause decreased excretion of renin by the kidneys, which acts to lower blood pressure as well. Propranalol is an example of a non-selective beta blocker. Because it can also affect the airways, propranalol (and other non-selective beta blockers) are avoided in patients with reactive airway disease such as asthma or COPD. What conditions are Beta Blockers used for?Beta blockers are used to treat more than just high blood pressure:
Drug Highlight: MetoprololLet’s take a deeper dive into the most common beta blocker you will see in the clinical setting: metoprolol. By now you’ve probably noticed that this class of drugs tends to end in “-olol.” While there are a few that do not, you can rely on this as a general rule of thumb. Metoprolol is typically prescribed to patients with hypertension, heart failure, angina and myocardial infarction. One interesting off-label use is as an anti-anxiety medication, in that it will combat the tachycardia and hypertension that typically accompany anxiety. Metoprolol is a cardioselective beta blocker, meaning it just targets those beta-1 receptors in the heart. So, if your patient has asthma and you see that the new resident has prescribed her propranolol (which targets both beta-1 and beta-2 receptors), it might be a good idea to advocate for a cardioselective beta blocker such as metoprolol. Metoprolol comes in a few different formulations: IV, tablet and extended-release tablet. A typical IV dose is 5mg q two minutes for up to three doses, while the extended release tablets range from 12.5 to 100mg (depending on what it’s being used for), and the regular tablets range from 25-100 mg per day in one or two doses (in general, of course). How will you monitor your patient?Because beta blockers lower the heart rate and blood pressure, you will need to monitor your patient for bradycardia and hypotension, including orthostatic hypotension. With that said, always get a blood pressure and heart rate prior to giving the dose. Most orders for metoprolol will have a hold parameter, meaning you’ll hold the medication if the heart rate is below 50 to 60 or the systolic blood pressure is below 90 or 100 (depends on the patient and MD’s orders). You’ll also want to monitor your patient for the more common side effects such as fatigue, pulmonary edema, and congestive heart failure. Because one of the side effects is CHF, monitoring daily weights and intake/output is also important, as is assessing lung sounds, edema, O2 saturation and work-of-breathing. What will you teach the patient?
TL;DR: Beta blockers block conduction at the AV Node, decrease heart rate and lower blood pressure. Watch your patient for bradycardia and hypotension. Typically you’ll hold for a HR below 50 or 60 and a BP below 90 or 100. Get this on audio on the Straight A Nursing podcast, episode 78.References Drugs.com. (n.d.-a). Beta blockers. Retrieved from https://www.drugs.com/mca/beta-blockers Drugs.com. (n.d.-b). List of Beta-adrenergic blocking agents (beta blockers)—Generics Only. Retrieved November 10, 2019, from Drugs.com website: https://www.drugs.com/drug-class/beta-adrenergic-blocking-agents.html EMS1.com. (2019). Receptors and the autonomic nervous system. Retrieved from EMS1 website: https://www.ems1.com/ems-products/education/articles/receptors-and-the-autonomic-nervous-system-StR9droX60aHgrfO/ Holland, N., & Adams, M. P. (2007). Core Concepts in Pharmacology (2nd ed.). Upper Saddle River, NJ: Pearson Prentice Hall. Klabunde, R. (n.d.). CV Pharmacology | Beta-Adrenoceptor Antagonists (Beta-Blockers). Retrieved November 10, 2019, from https://www.cvpharmacology.com/cardioinhibitory/beta-blockers Mayo Clinic. (n.d.). What you should know about beta blockers. Retrieved from Mayo Clinic website: https://www.mayoclinic.org/diseases-conditions/high-blood-pressure/in-depth/beta-blockers/art-20044522 Piascik, M. T. (n.d.). ADRENERGIC PHARMACOLOGY. Retrieved November 10, 2019, from http://www.uky.edu/~mtp/OBI836AR.html What do you monitor for metoprolol?Your blood pressure should be checked regularly to determine your response to metoprolol. Your doctor may ask you to check your pulse (heart rate). Ask your pharmacist or doctor to teach you how to take your pulse. If your pulse is faster or slower than it should be, call your doctor.
What adverse effects should the nurse monitor for a client on metoprolol?Adverse Reactions/Side Effects
CNS: fatigue, weakness, anxiety, depression, dizziness, drowsiness, insomnia, memory loss, mental status changes, nervousness, nightmares.
What are the main side effects of metoprolol?Side Effects. Blurred vision.. chest pain or discomfort.. dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position.. slow or irregular heartbeat.. What is metoprolol used for and side effects?Metoprolol is used with or without other medications to treat high blood pressure (hypertension). Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems. This medication is also used to treat chest pain (angina) and to improve survival after a heart attack.
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