What is the appropriate treatment for amlodipine and atenolol overdose?

Treatment of Amlodipine and Atenolol Overdose

For combined amlodipine and atenolol poisoning causing life-threatening hypotension or bradycardia, immediately initiate high-dose insulin euglycemia therapy (1 unit/kg/hour bolus, then 0.5-1 unit/kg/hour infusion) along with vasopressors (norepinephrine preferred), and consider early hemodialysis specifically for atenolol removal given its hydrophilic properties. 1

Initial Stabilization and Decontamination

Start with aggressive supportive care:

• Airway protection if altered mental status is present
• Gastric lavage if presenting within 1-2 hours of ingestion
• Activated charcoal (if airway protected and no contraindications)
• Whole bowel irrigation may be considered for sustained-release formulations
• Aggressive IV crystalloid resuscitation - but monitor closely for pulmonary edema, which can develop even with modest fluid volumes 2

Critical pitfall: Amlodipine has a long half-life (30-50 hours) and delayed onset of toxicity, so patients require extended monitoring even if initially stable. Effects may worsen over 6-12 hours post-ingestion.

Pharmacologic Management Algorithm

First-Line Therapy (Class I Recommendations)

1. High-Dose Insulin Euglycemia Therapy (HIET) 1

• Bolus: 1 unit/kg regular insulin IV
• Infusion: 0.5-1 unit/kg/hour, titrate up to 10 units/kg/hour if needed 3
• Concurrent dextrose: Start 0.5 g/kg/hour (D10W or D50W), adjust to maintain euglycemia
• Monitoring: Blood glucose every 15-30 minutes initially, then hourly; potassium every 2-4 hours
• Rationale: Improves myocardial contractility and has lower vasoconstrictive complications than vasopressors alone for both CCB and beta-blocker toxicity

Important: One case series showed dramatic improvement only occurred at maximum insulin doses (10 units/kg/hour), not at conventional 4 units/kg/hour 3. Don't hesitate to escalate rapidly.

2. Vasopressors 1

• Norepinephrine is preferred (doses up to 100 μg/min may be required)
• Start early - readily available and act quickly
• May require multiple agents (norepinephrine + epinephrine + vasopressin)

Second-Line Therapies (Class IIa Recommendations)

3. Calcium Salts 1

• Calcium chloride 10%: 10-20 mL (1-2 g) IV bolus, repeat every 15-20 minutes
• Continuous infusion: 0.2-0.4 mL/kg/hour calcium chloride 10%
• Target: Ionized calcium up to 2× normal may be more effective than lower doses 1
• Note: Most patients require additional therapies beyond calcium alone

4. Glucagon 1

• Bolus: 3-5 mg IV (or 0.05-0.15 mg/kg)
• Infusion: 2-10 mg/hour
• Limitations: Variable response rates, common vomiting, rapid tachyphylaxis
• Practical issue: Often unavailable 4

5. Atropine 1

• Dose: 0.5-1 mg IV, repeat as needed
• For hemodynamically significant bradycardia
• Caveat: Frequently ineffective, especially with severe toxicity

Extracorporeal Therapies

6. Hemodialysis for Atenolol 1, 5, 6

• Specific indication: Atenolol is hydrophilic and dialyzable (unlike amlodipine which is highly protein-bound)
• Consider early in severe atenolol poisoning with refractory shock
• Continuous veno-venous hemodialysis (CVVHD) has been used successfully 7
• Amlodipine is NOT effectively removed by dialysis due to high protein binding (98%)

7. VA-ECMO 1

• For refractory cardiogenic shock despite maximal pharmacologic therapy
• Survival rates up to 77% reported in CCB overdose
• Should be considered early rather than as last resort

Adjunctive/Rescue Therapies

8. Methylene Blue 1

• Specifically for refractory vasodilatory shock from amlodipine (dihydropyridine CCB)
• Dose: 1-2 mg/kg IV over 30 minutes
• Responses are mixed and may be transient
• Acts as nitric oxide synthase inhibitor

9. Angiotensin II 8, 9

• Emerging therapy for refractory shock, particularly when ACE inhibitors co-ingested
• May be especially beneficial in combined amlodipine-atenolol overdose due to impaired compensatory RAAS activation
• Dramatic hemodynamic improvement reported in case reports

10. Intravenous Lipid Emulsion (ILE) 1

• NOT recommended - Class III (No Benefit) for beta-blocker poisoning
• Large retrospective study found no benefit in CCB poisoning 1
• Despite this, some case reports describe use 4

Therapies with Limited Evidence

Electrical pacing 1: May be reasonable for hemodynamically significant bradydysrhythmias, but often ineffective, particularly with complete AV block or vasodilatory shock

Monitoring Requirements

• Continuous cardiac monitoring and blood pressure
• Blood glucose every 15-30 minutes during HIET initiation
• Serum potassium every 2-4 hours (risk of hypokalemia with HIET)
• Ionized calcium if using high-dose calcium therapy
• Lactate and acid-base status
• Renal function (acute kidney injury common) 7, 4
• Volume status (risk of pulmonary edema with aggressive fluids) 7, 10, 2

Key Clinical Pearls

Combination toxicity is worse: The synergistic effects of amlodipine (vasodilation, negative inotropy) and atenolol (bradycardia, negative inotropy) create profound cardiovascular collapse that is more refractory than either agent alone 7, 4, 3.

Timing matters: Don't wait for conventional therapies to fail before escalating to HIET and considering ECMO. Early aggressive management improves outcomes 7, 3.

Expect prolonged course: Amlodipine's long half-life means effects persist for days. Patients may require ICU support for 5-8 days 7, 4.

Beware fluid overload: These patients develop pulmonary edema easily, even with modest crystalloid volumes, due to increased capillary permeability and cardiac dysfunction 7, 10, 2.