Tricyclic Antidepressant Poisoning
Description Diagnostic criteria General and supportive measures Medicine treatment Referral ICD-10 code: T43.0 DESCRIPTION Poisoning with tricyclic antidepressants (TCAs) represent a large portion of poisoning fatalities. There is a high risk of tricyclic antidepressant toxicity in children because of its narrow therapeutic index. Serious toxicity may occur with low doses in children.
Description
Diagnostic criteria
General and supportive measures
Medicine treatment
Referral
ICD-10 code: T43.0
DESCRIPTION
Poisoning with tricyclic antidepressants (TCAs) represent a large portion of poisoning fatalities. There is a high risk of tricyclic antidepressant toxicity in children because of its narrow therapeutic index. Serious toxicity may occur with low doses in children. Patients can deteriorate rapidly.
DIAGNOSTIC CRITERIA
- Can cause anticholinergic syndromes.
- Mainly affects the cardiovascular and nervous systems leading to:
- QRS widening,
- ventricular dysrhythmias,
- hypotension,
- altered mental status,
- seizures.
GENERAL AND SUPPORTIVE MEASURES
- Gastric lavage for large ingestions or patients presenting within a few hours post ingestion, unless the patient is unconscious and the airway is not protected.
- Circulatory and respiratory support as needed.
- Cardiac and ECG monitoring for 48 hours.
MEDICINE TREATMENT
- Activated charcoal: see Poisoning, treatment.
- TCAs delay gastric emptying, therefore, activated charcoal may be effective for a longer period than usual.
For hypotension:
- Sodium chloride 0.9% or Ringer’s Lactate, IV bolus, 20 mL/kg.
Serum alkalinisation for all patients with:
- ventricular dysrhythmias,
- prolonged QRS > 100 ms,
- hypotension unresponsive to fluids, or
- seizures.
- Sodium bicarbonate, bolus doses (1–2 mEq/kg as an 8.4% solution), to achieve a pH of 7.45–7.55. (Specialist consultation with Poisons Information Centre if possible.)
- Monitor acid-base status, serum potassium and sodium.
In severe cases, inotropic support and anti-arrhythmic agents may be required in addition to serum alkalinisation. Hypotension is due to myocardial dysfunction and alpha-adrenergic vasodilation, therefore be careful to avoid fluid overload.
For seizures:
Note:
Phenytoin should be avoided (due to potential cardiotoxicity)
For circulatory and respiratory support:
See Chapter 1: Emergencies and Trauma, Cardiorespiratory arrest
REFERRAL
- Any cardiac arrhythmia.
Standard Treatment Guidelines and Essential Medicines List for South Africa, Hospital Level, Paediatrics, 2023 Edition
Chapter 18: Poisoning, 18.1 Poisoning, 18.1.3 Tricyclic Antidepressant Poisoning