Beta-blocker classes and pharmacology overview

Contributors: Preeya Prakash MD, Adam Greenhaw PharmD, Travis Barlock MD, and Jeffrey Olson MS4

In this episode, cardiologist Preeya Prakash and medical student Jeffrey Olson listen in as two cases are presented from EMM's recent event, Tox Talk 2025.

Talk 1- Digoxin Overdose

Dr. Adam Greenhaw presents a case of a Digoxin overdose along with many pearls. During the studio listen in, Dr. Prakash helps to answer the questions of:

• How does digoxin work?

• Why might a patient still be on digoxin in 2025?

• What are the EKG findings of digoxin toxicity?

• Is there any utility in atropine for bradycardia caused by digoxin?

• Should you use calcium to treat hyperkalemia in the setting of a digoxin overdose?

• If/when might a cardiologist get involved in a patient with a digoxin overdose?

Talk 2- Propranolol Overdose

Dr. Travis Barlock presents a case of a beta blocker overdose as well as many associated pearls. During our studio listen in, Dr. Prakash helps to answer the questions of:

• What are the different beta blockers and how do they work?

• If you are worried about a propranolol overdose, what medications do you want on hand?

• What POCUS cardiac view can give you the most information for different scenarios?

• Why or why not might transcutaneous or intravenous pacing be a good idea for a beta blocker overdose?

• If/when might you want a cardiologist to get involved in a patient with a beta blocker overdose?

References

• Alahmed AA, Lauffenburger JC, Vaduganathan M, Aldemerdash A, Ting C, Fatani N, Fanikos J, Buckley LF. Contemporary Trends in the Use of and Expenditures on Digoxin in the United States. Am J Cardiovasc Drugs. 2022 Sep;22(5):567-575. doi: 10.1007/s40256-022-00540-x. Epub 2022 Jun 24. PMID: 35739347; PMCID: PMC10263277.

• Chan BS, Buckley NA. Digoxin-specific antibody fragments in the treatment of digoxin toxicity. Clin Toxicol (Phila). 2014 Sep-Oct;52(8):824-36. doi: 10.3109/15563650.2014.943907. Epub 2014 Aug 4. PMID: 25089630.

• Hack JB, Wingate S, Zolty R, Rich MW, Hauptman PJ. Expert Consensus on the Diagnosis and Management of Digoxin Toxicity. Am J Med. 2025 Jan;138(1):25-33.e14. doi: 10.1016/j.amjmed.2024.08.018. Epub 2024 Sep 11. PMID: 39265879.

• Krenz JR, Kaakeh Y. An Overview of Hyperinsulinemic-Euglycemic Therapy in Calcium Channel Blocker and β-blocker Overdose. Pharmacotherapy. 2018 Nov;38(11):1130-1142. doi: 10.1002/phar.2177. Epub 2018 Oct 4. PMID: 30141827.

• Patocka J, Nepovimova E, Wu W, Kuca K. Digoxin: Pharmacology and toxicology-A review. Environ Toxicol Pharmacol. 2020 Oct;79:103400. doi: 10.1016/j.etap.2020.103400. Epub 2020 May 7. PMID: 32464466.

• Rotella JA, Greene SL, Koutsogiannis Z, Graudins A, Hung Leang Y, Kuan K, Baxter H, Bourke E, Wong A. Treatment for beta-blocker poisoning: a systematic review. Clin Toxicol (Phila). 2020 Oct;58(10):943-983. doi: 10.1080/15563650.2020.1752918. Epub 2020 Apr 20. PMID: 32310006.

Produced by Jeffrey Olson, MS4

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