What is the treatment for potassium channel blocker overdose?

Treatment for Potassium Channel Blocker Overdose

For potassium channel blocker overdose, high-dose insulin with glucose is the most reasonable first-line treatment for patients in refractory shock, followed by calcium administration and glucagon as adjunctive therapies. 1

Initial Management

• Standard resuscitation should follow BLS and ACLS algorithms for cardiac arrest cases 1
• Establish cardiac monitoring, secure airway if needed, and obtain IV access 1
• Fluid resuscitation should be administered as long as the patient demonstrates evidence of fluid responsiveness 1

First-Line Therapies

High-Dose Insulin Therapy

• Administer 1 U/kg regular insulin as IV bolus, followed by continuous infusion of 1 U/kg/hr 1
• Simultaneously administer 0.5 g/kg dextrose bolus, followed by continuous infusion of 0.5 g/kg/hr 1
• Titrate insulin infusion to achieve adequate hemodynamic response 1
• Titrate dextrose infusion to maintain serum glucose between 100-250 mg/dL (5.5-14 mmol/L) 1
• Monitor serum glucose very frequently (up to every 15 minutes) during initial phase 1
• Target potassium levels of 2.5-2.8 mEq/L; avoid aggressive potassium repletion 1
• Central venous access is required for sustained infusions of concentrated dextrose solutions (>10%) 1

Calcium Administration

• Administer 0.3 mEq/kg of calcium (0.6 mL/kg of 10% calcium gluconate or 0.2 mL/kg of 10% calcium chloride) IV over 5-10 minutes 1
• Follow with infusion of 0.3 mEq/kg per hour, titrated to hemodynamic response 1
• Monitor serum ionized calcium levels and avoid severe hypercalcemia 1
• Central venous access is required for sustained calcium infusions 1

Glucagon

• Administer IV glucagon for refractory shock 1
• Be aware that glucagon commonly causes vomiting; protect airway in patients with CNS depression 1
• Note that concomitant use of dopamine alone or with isoproterenol and milrinone may decrease glucagon effectiveness 1

Vasopressor Support

• Norepinephrine is recommended to increase blood pressure in vasoplegic shock 1
• Epinephrine is recommended to increase contractility and heart rate 1
• Dobutamine can be used in the presence of confirmed myocardial dysfunction 1
• High infusion rates of vasopressors and inotropes may be required 1
• Avoid dopamine due to inconsistent hemodynamic improvement 1

Rescue Therapies for Refractory Cases

Extracorporeal Life Support

• Consider ECMO for shock refractory to pharmacological therapy 1
• Intra-aortic balloon counterpulsation or ventricular assist devices may be lifesaving in critically hypotensive patients despite maximal therapy 1

Lipid Emulsion Therapy

• Consider IV lipid emulsion for refractory cases 1
• Evidence for lipid emulsion in potassium channel blocker overdose is mixed 1

Special Considerations

• Consult with a medical toxicologist or specialist with up-to-date knowledge when managing treatment-refractory hypotension 1
• Atropine may be considered for symptomatic bradycardia or conduction disturbances 1
• Pacemaker placement may be considered for unstable bradycardia or high-grade AV block without significant alteration in cardiac inotropism 1

Monitoring Parameters

• Continuous cardiac monitoring for arrhythmias and conduction abnormalities 1
• Frequent blood pressure measurements 1
• Serial ECGs to assess for QRS prolongation and conduction abnormalities 1
• Frequent monitoring of serum glucose, potassium, and calcium levels 1
• Assessment of cardiac function via echocardiography when available 1