Calcium channel blocker toxicity: Difference between revisions

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**I.e. may see decreased inotrophy, bradycardia
**I.e. may see decreased inotrophy, bradycardia


===Non-dihydropyridines (verapamil, diltiazem)===
====Non-dihydropyridines (verapamil, diltiazem)====
*Stronger effect on heart, weak vasodilators
*Stronger effect on heart, weak vasodilators
*Toxicity = Bradycardia, decreased inotropy
*Toxicity = Bradycardia, decreased inotropy
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==Differential Diagnosis==
==Differential Diagnosis==
#[[Beta-blocker toxicity|Beta blockers]]
*[[Beta-blocker toxicity|Beta blockers]]
##More likely to cause CNS changes
**More likely to cause CNS changes
##Hypoglycemia is more common
**Hypoglycemia is more common
#[[Digoxin toxicity|Digoxin]]
*[[Digoxin toxicity|Digoxin]]
##Nausea/vomiting is more common
**Nausea/vomiting is more common
#[[Clonidine toxicity|Clonidine]]
*[[Clonidine toxicity|Clonidine]]
##Miosis, somnolence
**Miosis, somnolence
#Cholinergic agents
*Cholinergic agents
##SLUDGE
**SLUDGE


==Diagnosis==
==Diagnosis==
#[[ECG]]
*[[ECG]]
##PR prolongation (varying degrees of AV block)
**PR prolongation (varying degrees of AV block)
###AV block occurs more commonly with verapamil
***AV block occurs more commonly with verapamil
##Bradydysrhythmia
**Bradydysrhythmia
#Glucose
*Glucose
#Chemistry
*Chemistry
##Serum calcium is often normal
**Serum calcium is often normal


== Treatment  ==
== Treatment  ==
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===High-dose insulin and glucose===
===High-dose insulin and glucose===
#Takes 30-60min for effect  
*Takes 30-60min for effect  
#Glucose:  
*Glucose:  
##Adult: 50mL of D50W  
**Adult: 50mL of D50W  
##Ped: 2.5mL/kg of D10  
**Ped: 2.5mL/kg of D10  
#Insulin bolus 1 unit/kg followed by 0.5units/kg/hr  
*Insulin bolus 1 unit/kg followed by 0.5units/kg/hr  
##Titrate infusion until hypotension is corrected or max 2u/kg/hr  
**Titrate infusion until hypotension is corrected or max 2u/kg/hr  
##Requires frequent glucose and K checks  
**Requires frequent glucose and K checks  
#Potassium  
*Potassium  
##If <3 administer 20mEq IV  
**If <3 administer 20mEq IV  
===Calcium===
===Calcium===
''Avoid if [[digoxin toxicity]] is possible''
''Avoid if [[digoxin toxicity]] is possible''
#Calcium gluconate 3g (30-60mL of 10% soln)  
*Calcium gluconate 3g (30-60mL of 10% soln)  
#Calcium chloride 1-3g IV bolus (10-20mL of 10% soln (requires large IV/central line)
*Calcium chloride 1-3g IV bolus (10-20mL of 10% soln (requires large IV/central line)
##Preferred over calcium gluconate because it provides triple the amount of calcium on a weight-to-weight basis <ref>Tintinalli's 7th Ed.</ref>
**Preferred over calcium gluconate because it provides triple the amount of calcium on a weight-to-weight basis <ref>Tintinalli's 7th Ed.</ref>
##Effects of calcium are transient
**Effects of calcium are transient
##Repeat dosing often required
**Repeat dosing often required
###Alternatively, can be given as an infusion: 2-6g/hour
***Alternatively, can be given as an infusion: 2-6g/hour


===Vasopressors===
===Vasopressors===
#[[Norepinephrine]] is agent of choice
*[[Norepinephrine]] is agent of choice


===Glucagon===
===Glucagon===
#5mg IV bolus q10min x 2  
*5mg IV bolus q10min x 2  
===Fluids===
===Fluids===
*Initial 20cc/kg bolus especially if source of hypotension is undifferentiated and also possibly hypovolemic or due to [[Sepsis]]
*Initial 20cc/kg bolus especially if source of hypotension is undifferentiated and also possibly hypovolemic or due to [[Sepsis]]
===Atropine===
===Atropine===
#Adult: 0.5-1mg IV q2-3min to max of 3g  
*Adult: 0.5-1mg IV q2-3min to max of 3g  
#Ped: 0.02mg/kg (minimum is 0.1mg)
*Ped: 0.02mg/kg (minimum is 0.1mg)


===When standard treatment fails===
===When standard treatment fails===
#Intravenous lipid emulsion  
*Intravenous lipid emulsion  
##1.5mL/kg of 20% lipid followed by 0.25mL/kg/minute
**1.5mL/kg of 20% lipid followed by 0.25mL/kg/minute
##Data show significant benefit in animals and case reports show promise in humans
**Data show significant benefit in animals and case reports show promise in humans
##If used, report on http://www.lipidrescue.org to contribute to the database
**If used, report on http://www.lipidrescue.org to contribute to the database


==Disposition==
==Disposition==

Revision as of 01:31, 7 June 2015

Background

  • Hemodialysis is ineffective
  • Precipitous deterioration is common (esp w/ verapamil)
  • Nifedipine can kill a child with a single pill

2 Classes

Dihydropyridines

  • Nifedipine, Amlodipine, Nicardipine
    • Systemic vasodilation, mild effect on heart
  • Toxicity = Hypotension, reflex tachycardia
  • With higher doses of toxicity peripheral selectivity is lost
    • I.e. may see decreased inotrophy, bradycardia

Non-dihydropyridines (verapamil, diltiazem)

  • Stronger effect on heart, weak vasodilators
  • Toxicity = Bradycardia, decreased inotropy

Clinical Features

Differential Diagnosis

  • Beta blockers
    • More likely to cause CNS changes
    • Hypoglycemia is more common
  • Digoxin
    • Nausea/vomiting is more common
  • Clonidine
    • Miosis, somnolence
  • Cholinergic agents
    • SLUDGE

Diagnosis

  • ECG
    • PR prolongation (varying degrees of AV block)
      • AV block occurs more commonly with verapamil
    • Bradydysrhythmia
  • Glucose
  • Chemistry
    • Serum calcium is often normal

Treatment

  • Monotherapy only successful for trivial overdoses


The majority of literature on calcium channel blocker overdose management is low-quality evidence and high-dose insulin and extracorporeal life support have the best evidence and other therapies such as include calcium, dopamine, norepinephrine, and lipid emulsion therapy may be beneficial but are poorly studied[1]

Charcoal

  • 1g/kg (max 50g) x1
    • Consider if present w/in 1-2hr w/ delayed-release preparation

High-dose insulin and glucose

  • Takes 30-60min for effect
  • Glucose:
    • Adult: 50mL of D50W
    • Ped: 2.5mL/kg of D10
  • Insulin bolus 1 unit/kg followed by 0.5units/kg/hr
    • Titrate infusion until hypotension is corrected or max 2u/kg/hr
    • Requires frequent glucose and K checks
  • Potassium
    • If <3 administer 20mEq IV

Calcium

Avoid if digoxin toxicity is possible

  • Calcium gluconate 3g (30-60mL of 10% soln)
  • Calcium chloride 1-3g IV bolus (10-20mL of 10% soln (requires large IV/central line)
    • Preferred over calcium gluconate because it provides triple the amount of calcium on a weight-to-weight basis [2]
    • Effects of calcium are transient
    • Repeat dosing often required
      • Alternatively, can be given as an infusion: 2-6g/hour

Vasopressors

Glucagon

  • 5mg IV bolus q10min x 2

Fluids

  • Initial 20cc/kg bolus especially if source of hypotension is undifferentiated and also possibly hypovolemic or due to Sepsis

Atropine

  • Adult: 0.5-1mg IV q2-3min to max of 3g
  • Ped: 0.02mg/kg (minimum is 0.1mg)

When standard treatment fails

  • Intravenous lipid emulsion
    • 1.5mL/kg of 20% lipid followed by 0.25mL/kg/minute
    • Data show significant benefit in animals and case reports show promise in humans
    • If used, report on http://www.lipidrescue.org to contribute to the database

Disposition

  • Admit all symptomatic pts
  • Admit all sustained-release ingestions
  • D/C if asymptomatic x 6-8hrs

See Also

References

  1. ↑ St-Onge M, et al. Treatment for calcium channel blocker poisoning: a systematic review. Clin Toxicol 2014 PDF
  2. ↑ Tintinalli's 7th Ed.
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