T43.0 + (X41.99/X61.99/Y11.99)
DESCRIPTION
Patients can deteriorate rapidly. They may have:
Mild to moderate poisoning:
- Sedation
- Tachycardia
- Anticholinergic effects:
- delirium,
- urinary retention, or
- dilated pupils,
- dry mouth.
Severe Poisoning:
- QRS widening, ventricular dysrhythmias
- Seizures
- Coma
- Pulmonary oedema
- Hypotension
GENERAL MEASURES
Do a baseline ECG in all patients.
- ICU admission for ventilatory/circulatory support, when indicated. Be prepared to intubate symptomatic patients early.
- Discharge patients only when
- asymptomatic, or
- mild symptoms/signs of toxicity and ECG has normalised for 24 hours.
MEDICINE TREATMENT
Tricyclic antidepressants delay gastric emptying, therefore activated charcoal may be effective for a longer period than usual.
- Serum alkalinisation for all patients with:
- ventricular dysrhythmias,
- prolonged QRS >100 msec
- hypotension unresponsive to fluids or
- seizures.
- Sodium bicarbonate, IV 1–2 mEq/kg as an 8.4% solution, as bolus doses to achieve a pH of 7.45–7.55 (Specialist consultation).
- Monitor acid-base status, serum potassium and sodium.
- If sodium bicarbonate is unavailable or fluid restrictions limit intake, consider hyperventilation of intubated patients.
In severe cases, inotropic support and anti-arrhythmics may be required (See Cardiac dysrhythmias ) in addition to serum alkalinisation. Hypotension is due to myocardial dysfunction and alpha-adrenergic vasodilation; be careful not to fluid overload the patient.
For seizures or if sedation is required for restlessness:
Treat with benzodiazepines - see section: 14.4.1 Status epilepticus.
Note: Phenytoin should be avoided (due to potential cardiotoxicity).
Note: The use of flumazenil is not recommended in any patient with mixed overdoses possibly including tricyclic antidepressants as it increases the risk of convulsions and dysrhythmias.