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

Management of Amlodipine Overdose

The cornerstone of management for amlodipine overdose includes high-dose insulin therapy combined with vasopressors and calcium administration, with advanced measures such as VA-ECMO for refractory cases. 1

Initial Assessment and Stabilization

• Initiate active cardiac and respiratory monitoring with frequent blood pressure measurements 2
• Monitor for clinical manifestations:
  • Hypotension (most common)
  • Bradycardia or reflex tachycardia
  • Altered mental status
  • Pulmonary edema 1

First-Line Interventions

1. Fluid Resuscitation

   • Judicious administration of IV fluids 2
   • Caution: Monitor for pulmonary edema which can develop even with relatively low-volume fluid replacement 3

2. Gastrointestinal Decontamination (if early presentation)

   • Activated charcoal administration 4
   • Consider whole bowel irrigation for large ingestions 3

3. Calcium Administration

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

Pharmacological Management

1. Vasopressors

   • Norepinephrine: Starting dose 2-10 mcg/min, titrate up to 100 μg/min as needed 1
   • Class 1 recommendation, Level B-NR evidence
   • Consider phenylephrine with attention to circulating volume and urine output 2

2. High-Dose Insulin Euglycemia Therapy (HIET)

   • Bolus: 1 U/kg IV
   • Infusion: 0.5-1 U/kg/hour
   • Maintain euglycemia with dextrose infusion
   • May require uptitration for hemodynamic improvement 1, 5
   • Insulin appears to have both inotropic and vasotropic properties in CCB toxicity 5

3. Atropine

   • For symptomatic bradycardia: 0.5-1 mg IV
   • May repeat to maximum of 3 mg 1
   • Class 2a recommendation, Level C-LD evidence

4. Glucagon

   • Bolus: 3-10 mg IV over 3-5 minutes
   • Followed by infusion of 3-5 mg/hour 1
   • Class 2b recommendation, Level C-LD evidence

Refractory Cases: Advanced Management

1. VA-ECMO

   • For refractory cardiogenic shock despite maximal pharmacological therapy
   • Reported survival rates up to 77% in CCB overdose 1, 6
   • Class 2a recommendation, Level C-LD evidence

2. Electrical Pacing

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

Important Considerations and Pitfalls

• Prolonged monitoring is essential: Amlodipine has a long elimination half-life and delayed onset of effects, requiring extended clinical monitoring 3

• Hemodialysis is unlikely to be beneficial as amlodipine is highly protein-bound 2

• Intravenous Lipid Emulsion (ILE) is not recommended for routine use in CCB poisoning (Class 3: No Benefit, Level C-LD) 1, though some case reports have included it in management protocols 4, 6

• Watch for complications: Hyperkalaemia may develop in severe cases 7

• Early escalation of therapy: Given the high mortality rate of CCB overdose, do not delay escalation to advanced therapies if first-line interventions fail to improve hemodynamics 6