From the Guidelines
High-dose insulin euglycemic therapy (HIET) is the recommended treatment for beta blocker overdose, as it has been shown to improve heart rate, hemodynamic parameters, and mortality in such cases. The recommended approach is to administer a bolus dose of regular insulin at 1 unit/kg followed by a continuous infusion at 0.5 units/kg/h, as stated in the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 1.
Some key points to consider when administering HIET include:
- Concurrent administration of dextrose is essential to maintain blood glucose between 100-200 mg/dL, typically as a 0.5 g/kg bolus of D50W followed by a D10W or D20W infusion.
- Close monitoring of blood glucose every 15-30 minutes initially, then hourly once stable, is crucial to prevent hypoglycemia.
- Potassium levels should also be monitored as insulin causes potassium to shift intracellularly, which can lead to hypokalemia.
- HIET works by improving cardiac contractility and vascular tone through enhanced carbohydrate metabolism in the heart, bypassing the blocked beta receptors.
- This therapy may take 15-60 minutes to show effect and should be continued until hemodynamic stability is achieved, which may require 24-48 hours in severe cases, as supported by the guideline 1.
It is also important to note that while glucagon and calcium are also used in the treatment of beta blocker overdose, HIET is a valuable option, particularly in cases where conventional therapies have failed to adequately reverse the cardiac depression and hypotension caused by beta blocker toxicity 1.
From the Research
Insulin Therapy for Beta Blocker Overdose
- High-dose insulin/euglycemia (HDIE) therapy is a targeted treatment for beta-blocker and calcium channel blocker overdose, as seen in a study published in 2022 2.
- The mechanisms of benefit for high-dose insulin include increased inotropy, increased intracellular glucose transport, and vascular dilatation, as discussed in a 2011 study 3.
- High-dose insulin dosing recommendations have been increased to 1 U/kg insulin bolus followed by a 1-10 U/kg/h continuous infusion, with some cases administering bolus doses up to 10 U/kg and continuous infusions as high as 22 U/kg/h 3.
Efficacy and Safety of High-Dose Insulin
- Animal models have shown high-dose insulin to be superior to calcium salts, glucagon, epinephrine, and vasopressin in terms of survival, as reported in a 2011 study 3.
- A 2018 case report demonstrated the effectiveness of high-dose insulin in improving hemodynamics in a patient with severe beta-blocker and calcium channel blocker overdose 4.
- High-dose insulin has been shown to reduce hypoglycemia when used with a guideline and concentrated insulin, as seen in a 2022 study 2.
Combination Therapy with Lipid Emulsion
- The combination of high-dose insulin and intravenous lipid emulsion therapy has been used to treat cardiogenic shock induced by intentional calcium-channel blocker and beta-blocker overdose, as reported in a 2014 case series 5.
- A 2018 case report also demonstrated the effectiveness of this combination therapy in improving hemodynamics in a patient with concurrent beta-blocker and calcium channel blocker overdose 6.
Clinical Considerations
- Physicians should consider high-dose insulin early in severe beta-blocker or calcium channel blocker overdose for improvement in hemodynamics, as suggested in a 2018 case report 4.
- Regular monitoring of glucose concentrations and supplementation of glucose is necessary to prevent hypoglycemia, as discussed in a 2011 study 3.