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Calcium Channel Blocker Overdose
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Calcium Channel Blocker Overdose
, Calcium Channel Blocker Toxicity
See Also
Calcium Channel Blocker
Beta Blocker Overdose
Drug
Overdose
Pathophysiology
Calcium Channel Blocker Overdose is treated similarly to
Beta Blocker Overdose
Hyperglycemia
in CCB (
Hypoglycemia
with BB)
Most severe
Overdose
effects are with
Non-Dihydropyridine
s (
Verapamil
,
Diltiazem
)
In
Overdose
,
Dihydropyridine
s lose their peripheral selectivity and suppress cardiac activity
Types
Presentation
Vasoplegic
Shock
Results from vasodilation due to
Dihydropyridine
Overdose
(e.g.
Amlodipine
)
Heart activity will be hyperdynamic on
Bedside Ultrasound
Skin is warm despite
Hypotension
Cardiogenic Shock
Results from decreased contractility and
Bradycardia
due to
Verapamil
or
Diltiazem
Overdose
Poor contractility on
Bedside Ultrasound
Appropriately cool skin (
Vasocon
striction)
Mixed Presentation
Calcium Channel Blocker
s lose their selectivity in
Overdose
Poor contractility on
Bedside Ultrasound
(as with
Cardiogenic Shock
)
Skin is warm despite
Hypotension
due to inappropriate vasodilation (as with vasoplegic shock)
Findings
Symptoms and Signs
Primary effects
Bradycardia
Hypotension
Arrhythmia
Other effects
Tachycardia
Coma
Dizziness
Lethargy
Seizure
s
Warm distal extremities (due to peripheral vasodilation)
Beta-islet cell blockade effects
Hyperglycemia
(Calcium Channel Blocker Overdose)
Insulin
exit from cell is via the same channel that CCB agents block
Calcium Channel Blocker
s result in relative
Insulin Resistance
and
Hyperglycemia
Serum Glucose
>250 mg/dl (without
Diabetes Mellitus
) suggests severe
Overdose
Contrast with
Beta Blocker Overdose
Associated with
Hypoglycemia
(due to beta-2
Adrenergic Receptor
block)
Cardiac
Muscle
reduced
Glucose
uptake
Fatty Acid
oxidation increased
Results in
Metabolic Acidosis
and in some cases,
Cardiogenic Shock
Management
Adults (
Beta Blocker
and
Calcium
channel
Overdose
)
Gastric Decontamination
(e.g.
Activated Charcoal
,
Gastric Lavage
,
Whole Bowel Irrigation
)
Consider if ingestion within last 1 hour, active bowel sounds and alert, cooperative patient (or airway secured)
Exercise
caution, as
Beta Blocker Overdose
patients rapidly decompensate and become obtunded
Epinephrine
Indicated for
Hypotension
or severe
Bradycardia
Start: 1 mcg/kg/min
Typically need to titrate to higher dose (esp.
Beta Blocker
s) to overcome
Catecholamine
blockade
Calcium Replacement
Calcium
infusion has transient stabilization effects
Do not be falsely reassured, as patient will once again decompensate after effects dissipate
Other measures must be simultaneously implemented
Calcium Gluconate
(10% solution, if
Peripheral IV Access
)
Bolus: 0.6 ml/kg (60 mg/kg up to 3 g) over 5-10 minutes
Next: Infuse at 0.6 to 1.5 ml/kg/hour
May give up to 3-6 ampule boluses of
Calcium Gluconate
in
Peri-Arrest
patients
Calcium Chloride
(if
Central IV Access
)
Bolus: 20 mg/kg (up to 1 g/dose)
May use one third of peripheral dose of
Calcium Gluconate
In
Peri-Arrest
or
Cardiac Arrest
, often used peripherally, despite risk of local adverse effects
Glucagon
Mechanism
Acts at cardiac cells, increasing intracellular
Calcium
and cAMP, increased myocardial contractions
Glucagon
bypasses blocked receptors, and allows
Calcium
influx (usually
Catecholamine
mediated)
Results in
Catecholamine
-independent receptor effects (sites not affected by BB or CCB)
Most effective in
Beta Blocker Overdose
(more than Calcium Channel Blocker Overdose)
Expect
Nausea
and
Vomiting
(
ALOC
patients may be at risk for aspiration)
Give
Antiemetic
when starting
Glucagon
Initial: 3 to 5 mg (50-150 mcg/kg) IV bolus slowly over 1-2 minutes
Next: May repeat at increased dose of 4 to 10 mg in 5 minutes if no effect
Next: Infusion at effective dose
Glucagon
in 5% dextrose solution at 3-5 mg/h (50-150 mcg/kg/h) for 12-48 hours
Maximum dose: 10 mg/h
Insulin
Euglycemia protocol
Indications
Vasoplegic shock with normal or depressed
Cardiac Function
Mechanism
Heart typically uses
Fatty Acid
s preferentially over
Carbohydrate
s
High dose
Insulin
promotes heart
Carbohydrate Metabolism
with direct inotropic effects
Insulin
also moves
Calcium
into
Myocyte
s and increases contractility
Onset of action in 15-60 minutes
Precautions
Keep
Serum Glucose
100-250 mg/dl
Insulin
doses are 10 fold higher than that used in
Diabetic Ketoacidosis
(high risk of
Hypoglycemia
)
Beta Blocker Overdose
is already at risk for
Hypoglycemia
(Unlike
Hyperglycemia
of CCB
Overdose
)
Start
Regular Insulin
1 IU/kg IV and
D50 given as 50 ml bolus IV if
Blood Glucose
<200 mg/dl
Have D50 available at bedside
Otherwise start dextrose infusion as below
Next (continued for 9 to 72 hours)
Regular Insulin
0.5 to 1 IU/kg/hour IV (
Central IV Access
preferred) and
D10 infused at 100 ml/h (or 0.5 g/kg/h) and titrate to
Blood Glucose
125 to 250 mg/dl
Typical adult dextrose doses are 15-30 grams per hour (typically up to 0.5 g/kg/h)
More concentrated dextrose infusion (e.g. D20W) may be used if
Central Line
access
Titrate
Insulin
every 15 to 30 minutes to target goals
Adjust dextrose infusion to maintain
Serum Glucose
125 to 250 mg/dl
Weaning
Insulin
may begin after
Vasopressor
s are stopped and patient hemodynamically stable
Start to wean
Insulin
by 1 unit/kg/hour
Continue dextrose infusion and monitor
Serum Glucose
for 24 hours
Goals
Heart Rate
>50 bpm
Mean Arterial pressure >= 65 mmHg or greater
Monitoring
Bedside
Glucose
Initial: Every 15-20 minutes
Later: Every 30-60 min (up to 120 min) once on stable dose of
Insulin
and dextrose
Serum Potassium
(risk of
Hypokalemia
)
Initial: Every 1 hour
Later: Every 6 hours once on stable dose of
Insulin
and dextrose
Consider
Magnesium
and
Phosphorus
monitoring
Other measures with variable efficacy
Intravenous Lipid Emulsion
(
Intralipid
)
Strongly consider for lipophilic agents (may be very effective)
May be effective for
Amlodipine
,
Verapamil
,
Betaxolol
,
Carvedilol
,
Metoprolol
,
Propranolol
,
Timolol
Sodium Bicarbonate
(1 mEq/ml solution)
Indicated for
QRS Widening
(due to
Sodium
channel blockade similar to TCA
Overdose
)
Dose: 50 mEq bolus
Methylene blue
Aggarwal (2013) BMJ Case Rep. +PMID:23334490 [PubMed]
Jang (2015) Ann Emerg Med 65(4): 410–415 [PubMed]
Extracorporeal Membrane Oxygenation
(
VA-ECMO
)
Indicated in refractory cases of
Cardiogenic Shock
or mixed presentation
Braud (2007) Critical Care [PubMed]
St Ange (2017) Crit Care Med 45(3): e306-15 [PubMed]
Vasopressor
s for
Hypotension
May be effective in
Hypotension
due to pure vasoplegic shock with hyperdynamic cardiac activity
However, less effective in
Cardiogenic Shock
or mixed presentation
Norepinephrine
doses are much higher than typical (as high as 100-300 mcg/min)
Contrast with typical
Norepinephrine
infusions maxing at 30 mcg/min
Closely monitor
Warmth of extremities (persistent vasodilation)
Cardiac Function
(hyperdynamic)
Consider adding
Vasopressin
to the
Norepinephrine
Consider
Epinephrine
for inotropic effect
Avoid ineffective measures
Atropine
Typically ineffective, but may be trialed
Cardiac pacing (typically ineffective)
Management
Children (
Beta Blocker
and
Calcium
channel
Overdose
)
See above for more detailed explanations under the adult dosing protocols
Consider
Gastric Decontamination
(as above)
Glucagon
Initial: 50-150 mcg/kg IV bolus
Next: May repeat in 3-5 minutes
Next: 0.1 mg/kg/hour infusion
Calcium Gluconate
(10% solution)
Bolus: 0.6 ml/kg (60 mg/kg) over 5-10 minutes
Next: Infuse at 0.6 to 1.5 ml/kg/hour
Epinephrine
Start: 1 mcg/kg/min (up to 10-30 mcg/min)
May need to titrate to higher dose
Insulin
Euglycemia protocol
See adult protocol above for more specific details
Children are higher risk of
Hypoglycemia
(esp. with
Beta Blocker Overdose
)
Keep
Serum Glucose
100-250 mg/dl
Start
Regular Insulin
1 IU/kg IV and
Dextrose 25 g IV
Next
Regular Insulin
0.5 IU/kg/hour IV and
Dextrose 0.5 g/kg/hour
Sodium Bicarbonate
(1 mEq/ml solution)
Indicated only if QRS interval widening >120 ms
Dose: 1-2 mEq/kg up to 50 mEq bolus
References
(2024) Presc Lett 31(8): 46-7
Hegg and Eyre (2017) Crit Dec Emerg Med 31(8): 11
Swaminathan, Weingart and Nordt in Herbert (2020) EM:Rap 20(3): 9-10
Yen (2015) Crit Dec Emerg Med 29(10): 18-23
Anderson (2005) Clin Pediatr Emerg Med 6(2): 109-15 [PubMed]
Kerns (2007) Emerg Med Clin North Am 25(2):309-31 [PubMed]
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