Treatment algorithm

Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer

ACUTE

all patients

1st line – observation and symptomatic care

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ACUTE
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all patients
1st line – 

observation and symptomatic care

The mainstay of treatment for most plant poisoning is symptomatic and supportive care. Very few plant exposures require any specific treatment or antidote.[40]

Asymptomatic patients who present for evaluation after consuming a potentially poisonous plant should be observed for several hours after ingestion, and efforts should be made to correctly identify the plant.

Consider – anti-emetics ± intravenous fluids

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ACUTE
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all patients
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with GI symptoms
Consider – 

anti-emetics ± intravenous fluids

Additional treatment recommended for SOME patients in selected patient group

Control of nausea, vomiting, abdominal cramping, and diarrhoea caused by plant toxin can be difficult. Treatment modalities including intravenous fluid, anti-emetics, and gastric acid-reducing agents may be employed, but are frequently inadequate to control the symptoms of plant-induced gastroenteritis.

Nausea may be treated with anti-emetics such as phenothiazines, benzodiazepines, metoclopramide, or 5-HT3 antagonists. Using phenothiazines for nausea or vomiting caused by plants that induce seizures or cardiac conduction delays (e.g., monkshood, yew, pennyroyal) should be avoided.

Patients are generally better within 24 hours and do not require treatment beyond this; however, it should be noted that metoclopramide should be used for up to 5 days only for any indication, in order to minimise the risk of neurological and other adverse effects. It is not recommended for this indication in children.[51]

Primary options

prochlorperazine: children >2 years of age: 0.4 mg/kg/day orally given in divided doses every 6-8 hours, or 0.1 to 0.15 mg/kg intramuscularly every 6-8 hours when required; adults: 10 mg orally every 6 hours when required, or 5-10 mg intravenously/intramuscularly every 4 hours when required, maximum 40 mg/day

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OR

diazepam: children: 0.12 to 0.8 mg/kg/day orally given in divided doses every 6-8 hours when required; adults: 5-10 mg orally/intravenously every 4-6 hours when required

OR

droperidol: children: 5 mg/m2 intravenously every 2-4 hours when required, maximum 6 doses in 24 hours; adults: 1.25 to 2.5 mg intravenously every 4 hours when required

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OR

ondansetron: children 8-14 kg of weight: 2 mg orally; children 15-30 kg of weight: 4 mg orally; children >30 kg of weight: 8 mg orally; adults: 0.15 mg/kg intravenously/intramuscularly every 8 hours

OR

granisetron: children: 10-20 micrograms/kg orally; adults: 2-4 mg orally once or twice daily

OR

promethazine: children >2 years of age: 0.25 to 1 mg/kg intramuscularly/orally every 4-6 hours when required; adults: 12.5 to 25 mg intramuscularly/orally every 4-6 hours when required

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Secondary options

metoclopramide: children ≥12 years of age and adults: consult specialist for guidance on dose

Consider – gastric acid-reducing agents

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ACUTE
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all patients
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with GI symptoms
Consider – 

gastric acid-reducing agents

Additional treatment recommended for SOME patients in selected patient group

Antacids, H2 antagonists, or proton-pump inhibitors may be used.

Note that cimetidine is metabolised through CYP 450 3A4 and has multiple pharmacodynamic drug interactions.

Primary options

bismuth subsalicylate: children 3-6 years of age: 5 mL orally every 2-4 hours when required, maximum 8 doses/day; children 7-9 years of age: 10 mL orally every 2-4 hours when required, maximum 8 doses/day; children 10-12 years of age: 15 mL orally every 2-4 hours when required, maximum 8 doses/day; children >12 years of age and adults: 30 mL orally every 2-4 hours when required

OR

aluminium hydroxide/magnesium hydroxide: 5-10 mL orally every 4 hours when required

Secondary options

famotidine: neonates and infants <3 months: 0.5 to 1 mg/kg orally once daily; children ≥3 months of age: 0.5 to 1 mg/kg orally twice daily, maximum 80 mg/day; adults: 20-40 mg orally once or twice daily

OR

cimetidine: neonates: 5-20 mg/kg intravenously/intramuscularly/orally every 6-12 hours; infants: 10-20 mg/kg intravenously/intramuscularly/orally every 6-12 hours; children: 20-40 mg/kg intravenously/intramuscularly/orally every 6 hours; adults: 300 mg intravenously/intramuscularly/orally every 6 hours, maximum 2400 mg/day

Tertiary options

omeprazole: children: 0.6 to 0.7 mg/kg orally once daily; adults: 20 mg orally once daily

OR

esomeprazole: adults: 20-40 mg intravenously once daily

OR

pantoprazole: adults: 40 mg intravenously once daily

Consider – N-acetylcysteine

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ACUTE
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all patients
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with hepatic toxicity
Consider – 

N-acetylcysteine

Additional treatment recommended for SOME patients in selected patient group

Patients who develop hepatic toxicity and injury caused by hepatotoxic plants, or who are at risk for hepatotoxicity, may benefit from intravenous or oral N-acetylcysteine.[41]

Primary options

acetylcysteine: adults: 150 mg/kg intravenously over 1hour, followed by 50 mg/kg over 4 hours, followed by 100 mg/kg over 16 hours; OR 140 mg/kg orally, followed by 70 mg/kg orally/intravenously every 4 hours

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Consider – referral to liver transplant centre

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ACUTE
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all patients
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with hepatic toxicity
Consider – 

referral to liver transplant centre

Additional treatment recommended for SOME patients in selected patient group

Patients who demonstrate continued acidosis (pH <7.3) despite maximal resuscitative efforts, or who demonstrate continued deterioration of hepatic synthetic function (coagulopathy), should be referred to a liver transplant centre for optimal management of their hepatotoxicity. Evidence of liver injury and elevation of serum aminotransferases or bilirubin are not in and of themselves reasons for liver transplantation.

Consider – benzodiazepine

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ACUTE
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all patients
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with tachycardia/hypertension
Consider – 

benzodiazepine

Additional treatment recommended for SOME patients in selected patient group

Standard treatments of tachycardia, including intravenous benzodiazepines to sedate the patient and reduce catecholamine outflows, are indicated in poisonings that cause sympathomimetic or antimuscarinic cardiac effects.

Primary options

lorazepam: children: 0.05 mg/kg intravenously every 4-8 hours when required; maximum 2 mg/dose; adults: 2 mg intravenously every 1-2 hours when required

OR

diazepam: children: 0.04 to 0.2 mg/kg every 2-4 hours when required; maximum 0.6 mg/kg each 8 hours; adults: 5-10 mg intravenously every 1-2 hours when required

OR

midazolam: children 6 months to 5 years of age: 0.05 to 0.1 mg/kg intravenously every 2-3 min, maximum 6 mg; children 6-12 years of age: 0.025 to 0.05 mg/kg intravenously every 2-3 min, maximum 10 mg; adults: 2-4 mg intravenously every 1-2 hours when required, maximum 10 mg

Consider – atropine

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ACUTE
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all patients
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with bradycardia/hypotension
Consider – 

atropine

Additional treatment recommended for SOME patients in selected patient group

Bradycardia should be treated according to the severity of haemodynamic embarrassment and presence of intraventricular conduction delays, with the use of atropine and vasopressors/inotropes or pacemaker as indicated.

Primary options

atropine: children: 0.02 mg/kg intravenously every 5 minutes, maximum 1 mg; adults: 0.5 mg intravenously every 3-5 minutes, maximum 3 mg

Consider – vasopressor/inotropes or pacemaker

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ACUTE
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all patients
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with bradycardia/hypotension
Consider – 

vasopressor/inotropes or pacemaker

Additional treatment recommended for SOME patients in selected patient group

Bradycardia should be treated according to the severity of haemodynamic embarrassment and presence of intraventricular conduction delays, with the use of atropine and vasopressors/inotropes or pacemaker as indicated.

Consider – digoxin immune Fab

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ACUTE
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all patients
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with bradycardia/hypotension
Consider – 

digoxin immune Fab

Additional treatment recommended for SOME patients in selected patient group

Several case reports describe the use of digoxin immune Fab (digoxin-specific antibody fragments) for the treatment of bradycardia and hypotension in patients poisoned after ingesting concentrates of plants that contain cardiac glycosides. It is best documented for oleander ingestions.

Dosing recommendations are empirical and based on clinical findings. This includes 30 vials in critically ill or unstable patients with more selective dosing (initial dose of 5 vials, and titrate by 5 vial increments, depending upon severity) in stable symptomatic patients.[9][52]

Dosing is administered intravenously over 15 to 30 minutes with maximum effect seen within 1 to 3 hours. End-point is determined by resolution of dysrhythmia, hypotension, and normokalaemia.

Because the serum digoxin level is not 100% cross-reacting in plant poisonings, the level should not be used to dose digoxin immune Fab. The dosing is similar in children as adults; however, fluid overload must be considered when higher doses are required.[52]

Primary options

digoxin immune Fab: consult specialist for guidance on dose

Consider – sodium bicarbonate ± potassium repletion if hypokalaemic

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ACUTE
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all patients
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with QRS prolongation >100 milliseconds
Consider – 

sodium bicarbonate ± potassium repletion if hypokalaemic

Additional treatment recommended for SOME patients in selected patient group

Patients who have ingested cardiotoxic plants that cause prolongations of the QRS complex to >100 milliseconds should receive serum alkalinisation with intravenous sodium bicarbonate.

Sodium bicarbonate should be administered by direct intravenous injection at 1-2 mEq/kg, followed by a continuous infusion of 150 mEq/L of sodium bicarbonate in 5% dextrose injection at 200-250 mL/minute (1/5-2X maintenance fluids). Titrate to serum pH between 7.45-7.55. Hypokalaemia (potassium <3.8 mEq/L) may be induced by sodium bicarbonate shifting potassium intracellularly; therefore, potassium repletion is needed.

Consider – benzodiazepine

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ACUTE
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all patients
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with seizures
Consider – 

benzodiazepine

Additional treatment recommended for SOME patients in selected patient group

Neurological toxicity caused by plant poisoning should be treated with benzodiazepines to reduce catecholamines and elevate the seizure threshold.

Primary options

lorazepam: children: 0.05 mg/kg intravenously every 4-8 hours when required, maximum 2 mg/ dose; adults: 2 mg intravenously every 1-2 hours when required

OR

diazepam: children: 0.04 to 0.2 mg/kg intravenously every 2-4 hours when required, maximum 0.6 mg/kg every 8 hours; adults: 5-10 mg intravenously every 1-2 hours when required

OR

midazolam: children 6 months to 5 years of age: 0.05 to 0.1 mg/kg intravenously every 2-3 min, maximum 6 mg; children 6-12 years of age: 0.025 to 0.05 mg/kg intravenously every 2-3 min, maximum 10 mg; adults: 2-4 mg intravenously every 1-2 hours when required, maximum 10 mg

Consider – phenobarbital or propofol

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ACUTE
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all patients
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with seizures
Consider – 

phenobarbital or propofol

Additional treatment recommended for SOME patients in selected patient group

Because much of plant-induced seizure activity is related to gamma-aminobutyric acid (GABA) inhibition, other GABA agents besides benzodiazepines may be helpful. This includes the barbiturates such as phenobarbital. Phenobarbital is an anticonvulsant that may be useful because it has a long duration of action and may control multiple, repeat seizures caused by plants. It also acts synergistically with benzodiazepines. Respiratory depression is possible at high doses.

Propofol may be an alternative agent because of its GABA agonism and N-methyl-D-aspartate (NMDA) receptor antagonism. However, the anticonvulsant effect of propofol will cease when the drug is discontinued.

Primary options

phenobarbital: 5 mg/kg intravenously every 15-30 min to a total dose of 15-20 mg/kg

OR

propofol: 5 micrograms/kg/min intravenously for 10-15 minutes, then increase by 5-10 micrograms/kg/min increments every 10-15 minutes when required to achieve a state of general anaesthesia and EEG burst suppression

Consider – cyanide antidote

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ACUTE
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all patients
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with ingestion of cyanogenic glycoside-containing plants
Consider – 

cyanide antidote

Additional treatment recommended for SOME patients in selected patient group

Although not described in the literature, symptomatic patients poisoned with cyanogenic glycosides (e.g., cassava or prunus plants) should be treated with a cyanide antidote.

Dosing recommendations should follow those for routine use of the cyanide antidotes.

Nithiodote® contains sodium nitrite and sodium thiosulfate. Cyanokit® contains hydroxocobalamin. Sodium nitrite may cause hypotension. Hydroxocobalamin can cause red discoloration of the skin and affect colorimetric lab tests (creatinine, LFTs). The brand names of these kits are US brand names and they may differ in other countries; consult your local drug formulary or protocol.

If cyanide antidotes are not available, good supportive measures (including oxygenation and intubation) are often associated with good outcomes.

Primary options

sodium nitrite: refer to local specialist protocol for dosing

and

sodium thiosulfate: refer to local specialist protocol for dosing

OR

hydroxocobalamin: refer to local specialist protocol for dosing

Consider – transfusions as required + monitoring for infection

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ACUTE
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all patients
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with haematological toxicity/myelotoxicity
Consider – 

transfusions as required + monitoring for infection

Additional treatment recommended for SOME patients in selected patient group

If the patient exhibits anaemia, blood transfusion may be necessary.

If the patient exhibits thrombocytopenia, then platelets may need to be transfused.

Pancytopenia and a general decrease in all blood cell lines including leukocytes (neutropenia) will result in the patient becoming immunocompromised, requiring exquisite vigilance to monitor for infections. The use of erythropoietin or a granulocyte-stimulating factor may be a useful adjunct.

Consider – phytomenadione (vitamin K) as required

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ACUTE
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all patients
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with bleeding/elevated INR
Consider – 

phytomenadione (vitamin K) as required

Additional treatment recommended for SOME patients in selected patient group

If bleeding is caused by ingestion of plant-derived coumarin compounds, phytomenadione (vitamin K) may have a role in helping to reverse the coagulopathy. Recommendations regarding the management of patients on vitamin K antagonist therapy with elevated INR can be amended to apply to individuals who have developed coagulopathy as a result of ingestion of plant-derived coumarin derivatives, according to local specialist protocol.[47]

Primary options

phytomenadione: refer to local specialist protocol for dosing

Consider – topical emollient and corticosteroid

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ACUTE
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all patients
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with dermatological toxicity
Consider – 

topical emollient and corticosteroid

Additional treatment recommended for SOME patients in selected patient group

After decontamination with soap and water, most dermatological manifestations of plant toxicity can be treated with topical emollients and corticosteroids.

Primary options

hydrocortisone topical: (1% to 2.5%) apply to affected area(s) three to four times daily when required

Consider – cardiopulmonary monitoring + fluid resuscitation

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ACUTE
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all patients
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with nicotinic toxicity
Consider – 

cardiopulmonary monitoring + fluid resuscitation

Additional treatment recommended for SOME patients in selected patient group

Supportive care is paramount, with careful cardiac and pulmonary monitoring and intravenous fluid supplementation and replacement to correct acidaemia.

Consider – cardiopulmonary monitoring, temperature monitoring, fluid resuscitation ± physostigmine or rivastigmine

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ACUTE
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all patients
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with antimuscarinic toxicity
Consider – 

cardiopulmonary monitoring, temperature monitoring, fluid resuscitation ± physostigmine or rivastigmine

Additional treatment recommended for SOME patients in selected patient group

Antimuscarinic toxicity is treated primarily with supportive care, cardiopulmonary and temperature monitoring, and intravenous fluid hydration.[50]

Physostigmine may be indicated in patients with a clear antimuscarinic toxidrome and serious central toxicity with an altered mental status, particularly delirium, requiring chemical and/or physical restraint. The use of physostigmine for antimuscarinic toxicity is increasing, and there is growing evidence that it is safe and has minimal cholinergic side effects.[48][49]​ Physostigmine is not commercially available in the US, but may it be available via a temporary importation service via the Food and Drug Administration.[38][39]​ Physostigmine may also not be available in other countries; consult your local drug formulary.

An ECG is recommended prior to using physostigmine as it can cause arrhythmias. It is not recommended in patients with suspected or known tricyclic antidepressant intoxication. It may cause nausea, vomiting, diarrhoea, seizures which can be treated with atropine. Consultation with a poison centre is recommended prior to using physostigmine, and it should be given in a monitored environment.

If physostigmine is not available, some experts recommend using rivastigmine; however, this is an off-label use.[50]

Primary options

physostigmine: refer to local specialist protocol for dosing

Secondary options

rivastigmine: refer to local specialist protocol for dosing

Consider – cardiopulmonary monitoring, temperature monitoring + fluid resuscitation

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ACUTE
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all patients
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with muscarinic toxicity
Consider – 

cardiopulmonary monitoring, temperature monitoring + fluid resuscitation

Additional treatment recommended for SOME patients in selected patient group

Cholinomimetic poisonings are treated primarily with supportive care, cardiopulmonary and temperature monitoring, and intravenous fluid hydration.

Consider – atropine or ipratropium

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ACUTE
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all patients
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with muscarinic toxicity
Consider – 

atropine or ipratropium

Additional treatment recommended for SOME patients in selected patient group

Atropine is used to treat bronchorrhoea, bronchospasm, bradycardia, and pulmonary oedema; it is given along with supplemental oxygen, adjunctive respiratory assistance, endotracheal intubation, and mechanical ventilation if necessary.

Ipratropium may be useful in relieving bronchospasm.

Primary options

atropine: children: consult specialist for guidance on dose; adults: 2 mg intravenously initially, followed by double doses (e.g., 4 mg, 8 mg, 16 mg, etc.) every 5 minutes until secretions are controlled

OR

ipratropium inhaled: (20-40 micrograms) 1-2 puffs every 6-8 hours: or 250-500 micrograms nebulised every 6-8 hours

Consider – chemical cardioversion or external circulatory assist (intra-aortic balloon pump assist or extracorporeal membrane oxygenation or left ventricular assist device or cardiopulmonary bypass)

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ACUTE
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all patients
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with aconitine-related ventricular dysrhythmia
Consider – 

chemical cardioversion or external circulatory assist (intra-aortic balloon pump assist or extracorporeal membrane oxygenation or left ventricular assist device or cardiopulmonary bypass)

Additional treatment recommended for SOME patients in selected patient group

Magnesium sulfate, flecainide, and amiodarone are first-choice therapies for aconitine-related ventricular dysrhythmia, which is frequently refractory to cardioversion. If ventricular dysrhythmia occurs with prolonged QTc, amiodarone may not be appropriate because it blocks potassium cellular flux. If these treatments fail and cardiogenic shock is present, intra-aortic balloon pump assist, extracorporeal membrane oxygenation, left ventricular assist device, or cardiopulmonary bypass may be considered.[10][43][44][45][46]

Primary options

magnesium sulfate: children: 25-50 mg/kg intravenously over 10-20 minutes, maximum 2 g/dose; adults: 1-2 g intravenously over 5-20 minutes initially, followed by 3-20 mg/minute infusion (maximum 12 g/24 hours)

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OR

amiodarone: children and adults: consult specialist for guidance on dose

OR

flecainide: children: consult specialist for guidance on dose; adults: 200-300 mg orally as a single dose

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Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups. See disclaimer

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