Beta blocker toxicity
|Beta blocker toxicity|
|Other names||Beta blocker poisoning, beta blocker overdose|
|A 20% lipid emulsion may be used for beta blocker toxicity|
|Symptoms||Slow heart rate, low blood pressure|
|Complications||Irregular heartbeat, low blood sugar|
|Usual onset||Within 2 hours|
|Causes||Too much beta blockers either by accident or on purpose|
|Differential diagnosis||Calcium channel blocker toxicity, acute coronary syndrome, hyperkalemia|
|Treatment||Activated charcoal, whole bowel irrigation, intravenous fluids, sodium bicarbonate, glucagon, high dose insulin, vasopressors, lipid emulsion, ECMO|
|Prognosis||High risk of death|
Beta blocker toxicity is the taking of too much of the medications known as beta blockers, either by accident or on purpose. This often causes a slow heart rate and low blood pressure. Some beta blockers can also cause an irregular heartbeat or low blood sugar. Symptoms usually occur in the first two hours but with some forms of the medication may not start until 20 hours. A person may be medically cleared if they have no symptom 6 hours after taking an immediate release preparation.
Beta blockers include metoprolol, bisoprolol, carvedilol, propranolol, and sotalol. ECG changes may include PR prolongation and a wide QRS. Measuring blood levels of beta blockers is not useful. Other conditions that may present similarly include calcium channel blocker toxicity, acute coronary syndrome, and hyperkalemia.
Treatment may include efforts to reduce absorption of the medication including: activated charcoal taken by mouth if given shortly after the ingestion or whole bowel irrigation if an extended release formula was taken. Efforts to bring about vomiting are not recommended. Medications to treat the toxic effects include: intravenous fluids, sodium bicarbonate, glucagon, high dose insulin, vasopressors and lipid emulsion. Extracorporeal membrane oxygenation and electrical pacing may also be options. Some beta blockers may be removable by dialysis.
Beta blocker toxicity is relatively uncommon. Along with calcium channel blockers and digoxin beta blockers have one of the highest rates of death in overdose. These medications first became available in the 1960s and 1970s.
The preferred vasopressor is generally epinephrine, though norepinephrine may be used in those who have a normal heart rate. Dopamine is not generally recommended. High doses may be required.
Insulin is often recommended at an initial dose of 0.5 to 1 unit per kilogram followed by an ongoing dose of 0.5 to 1 unit per kilogram per hour. This may be increased up to 10 units per kilogram per hour. This should be given together with dextrose, initially 25 grams and than followed by a dose of 0.5 grams per kilogram per hour.
- Palatnick, Wesley (September 2020). "Calcium-Channel Blocker, Beta Blocker, and Digoxin Toxicity Management Strategies". www.ebmedicine.net. Retrieved 27 December 2020.
- Khalid, MM; Galuska, MA; Hamilton, RJ (January 2020). "Beta-Blocker Toxicity". PMID 28846217. Cite journal requires
- Marx, John A. Marx (2014). "Cardiovascular Drugs". Rosen's emergency medicine: concepts and clinical practice (8th ed.). Philadelphia, PA: Elsevier/Saunders. pp. Chapter 152. ISBN 1455706051.
- Wall, Ron (2017). Rosen's Emergency Medicine: Concepts and Clinical Practice (9 ed.). Elsevier. p. 1881. ISBN 978-0323354790.