What is the management for an amlodipine (calcium channel blocker) overdose?

Management of Amlodipine Overdose

High-dose insulin therapy combined with vasopressors and calcium administration is the cornerstone of management for severe amlodipine overdose with hemodynamic instability. 1

Initial Assessment and Monitoring

• Continuous cardiac monitoring, frequent blood pressure measurements, and respiratory assessment are essential 1
• Clinical presentation typically includes hypotension, bradycardia or reflex tachycardia, altered mental status, and pulmonary edema 1
• Initiate active cardiac and respiratory monitoring immediately 2

Treatment Algorithm

First-Line Interventions

1. Decontamination

   • Gastric lavage if presentation is within 1-2 hours of ingestion 3
   • Activated charcoal administration 4
   • Consider whole bowel irrigation for large ingestions 4

2. Hemodynamic Support

   • Intravenous fluids (judicious administration to avoid pulmonary edema) 2
   • Elevation of extremities 2
   • Monitor for early signs of pulmonary edema, which can develop even with relatively low-volume fluid replacement 4

3. Calcium Administration

   • 10% calcium chloride or 10% calcium gluconate (Class 2a, Level C-LD) 1
   • Target ionized calcium concentrations up to twice normal 1

Second-Line Interventions (for persistent hypotension)

1. Vasopressors

   • Norepinephrine (first choice): Starting dose 2-10 mcg/min, titrate up to 100 μg/min as needed (Class 1, Level B-NR) 1
   • Phenylephrine may also be considered 2

2. High-Dose Insulin Euglycemia Therapy (HIET)

   • Bolus dose: 1 U/kg IV 1
   • Infusion: 0.5-1 U/kg/hour, titrate as needed 1
   • May require doses up to 10 units/kg/hour in severe cases 5
   • Maintain euglycemia with dextrose 10% infusion 5
   • Close glucose monitoring is essential 1
   • Note: Insulin therapy has shown dose-dependent hemodynamic improvement, often within 30 minutes 5, 6

3. Additional Pharmacological Interventions

   • Atropine 0.5-1 mg IV for symptomatic bradycardia, may repeat to maximum of 3 mg (Class 2a, Level C-LD) 1
   • Glucagon: 3-10 mg IV bolus over 3-5 minutes, followed by infusion of 3-5 mg/hour (Class 2b, Level C-LD) 1

Refractory Cases

1. VA-ECMO

   • Consider for refractory cardiogenic shock despite maximal pharmacological therapy (Class 2a, Level C-LD) 1
   • Reported survival rates up to 77% in CCB overdose 1

2. Electrical Pacing

   • For refractory bradyarrhythmias (Class 2b, Level C-LD) 1
   • May be ineffective in complete AV nodal blockade or vasodilatory shock 1

3. Other Considerations

   • Plasmapheresis has been attempted in severe cases 7
   • Methylene blue has been used for refractory hypotension 7
   • Note: Hemodialysis is unlikely to be beneficial as amlodipine is highly protein-bound 2

Important Caveats and Pitfalls

1. Prolonged Monitoring Required

   • Amlodipine has a long elimination half-life and delayed onset of effects 4
   • Extended clinical monitoring is necessary even after apparent stabilization

2. Intravenous Lipid Emulsion (ILE)

   • Not recommended for routine use in CCB poisoning (Class 3: No Benefit, Level C-LD) 1
   • Has been used in case reports with mixed results 3, 7

3. Fluid Administration

   • Risk of pulmonary edema with aggressive fluid resuscitation 4
   • Balance between adequate volume resuscitation and avoiding pulmonary edema

4. Insulin Therapy Considerations

   • Insulin appears to have both inotropic and vasotropic properties in CCB overdose 5
   • May be more effective than traditional vasopressors in some cases 6
   • Consider as early intervention rather than rescue therapy 6

5. Concomitant Overdoses

   • Be alert for co-ingestions that may complicate management 3
   • Combined beta-blocker and calcium channel blocker overdose is particularly challenging 3