| To obtain emergency consultation with a medical toxicologist, in the United States, call 1-800-222-1222 for the nearest regional poison control center. Contact information for poison control centers around the world is available at the WHO website and in the UpToDate topic on regional poison control centers (society guideline links). |
| Clinical and laboratory features |
- Hypotension and bradycardia are often prominent with significant ingestions
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- Electrocardiogram can show PR prolongation or any bradydysrhythmia
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- Ingestion of beta-blockers with membrane-stabilizing activity (eg, propranolol, carvedilol) may cause QRS prolongation and seizures
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- Laboratory findings may include hyperkalemia and hypoglycemia
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- Patients with beta blocker poisoning can deteriorate rapidly
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| Diagnostic evaluation |
- Assays for beta-blockers are not routinely available and do not aid management
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- Diagnosis is made on the basis of the history and clinical findings
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- Differential diagnosis for unexplained bradycardia also includes poisoning with calcium channel blockers, digoxin, clonidine, and cholinergic agents
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- Structural heart disease and myocardial ischemia may cause similar findings and must be excluded
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| Treatment |
| Stabilize airway, breathing, and circulation: |
- Administer IV bolus crystalloid for hypotension (500 to 1000 mL isotonic saline)
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- Administer atropine 1 mg IV for bradycardia and hypotension; may repeat up to 3 total doses
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| For severe poisoning (eg, profound hypotension refractory to crystalloid boluses and atropine), give ALL of the following treatments: |
- IV glucagon, IV calcium salt, vasopressor, IV high dose insulin and dextrose, and IV lipid emulsion therapy
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| For patients with milder symptoms, give the following treatments in succession, but proceed to the next treatment only if the prior treatment or combination of treatments is ineffective: |
- IV crystalloid (for hypotension, as above), IV atropine (for bradycardia and hypotension, as above), IV glucagon, IV calcium salt, vasopressor, IV high dose insulin and dextrose, and IV lipid emulsion therapy
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| Gastrointestinal decontamination: |
- Give a single dose of activated charcoal (1 g/kg, up to 50 g maximum) to all patients who present within 2 hours of ingestion, unless contraindicated (eg, depressed mental status and not intubated)
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- Give whole bowel irrigation (2 L/hour by mouth until clear rectal effluent) for potentially life-threatening ingestion of extended-release preparation
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| Dosing regimens: |
| Intravenous calcium (hypotension and/or bradycardia) |
- Bolus therapy (select one):
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- Calcium chloride – 10 to 20 mL of 10% solution (via central venous access if possible), or
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- Calcium gluconate – 30 to 60 mL of 10% solution
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- 0.5 meq calcium/kg per hour
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- Monitor serum calcium and ECG for evidence of hypercalcemia
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| Glucagon (bradycardia) |
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- 1 to 5 mg IV push, may repeat up to 15 mg total
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- Determine bolus amount needed to obtain response; give this "response dose" every hour as continuous infusion
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| Vasopressor (hypotension) |
- Norepinephrine – begin 2 mcg/minute IV, titrate rapidly to systolic blood pressure 100 mmHg
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| High dose insulin with dextrose (hypotension) |
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- Regular insulin – 1 Unit/kg IV
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- Dextrose – 25 to 50 grams IV; repeat for hypoglycemia; hold if serum glucose >300 mg/dL [16.7 mmol/L]; give potassium for hypokalemia (hypomagnesemia often associated with hypokalemia)
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- Regular insulin – start infusion at 0.5 Units/kg per hour IV; titrate upwards until hypotension corrected or maximum dose of 10 Units/kg per hour reached
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- Dextrose – 0.5 grams/kg per hour; titrate to euglycemia; Measure blood glucose (eg, fingerstick) every 15 to 30 minutes until infusion rate is steady and glucose measurements are stable; thereafter, measure glucose and potassium every 1 to 2 hours while infusion continues
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| Intravenous lipid emulsion (20% solution) |
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- 15 mL/kg over 60 minutes (0.25 mL/kg per minute)
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| Additional interventions: |
- The following therapies may be necessary if the patient fails to improve with the interventions above or specific complications arise:
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- Sodium bicarbonate for QRS prolongation
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- Magnesium for ventricular arrhythmia
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- Transvenous cardiac pacing for profound bradycardia
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- Intraaortic balloon pump for refractory hypotension
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