Serum alkalinisation is the cornerstone of treatment for amitriptyline poisoning

A 28-year-old woman was admitted in a comatose state following ingestion of 5 g of amitriptyline. On arrival, there was intermittent seizure activity and a broad complex tachycardia on the ECG. Immediate resuscitation included 8 mg lorazepam, 2 L crystalloid fluid, 100 mL 8.4% sodium bicarbonate, 2 g of magnesium sulphate and lipid emulsion infusion. Despite this, the broad complex tachycardia persisted with haemodynamic instability. The case was discussed with the National Poisons Information Service, which advised further 8.4% sodium bicarbonate to achieve serum alkalinisation. Following this, the QRS duration reduced and haemodynamic stability was achieved. Serum alkalinisation continued in the intensive treatment unit before the patient was successfully extubated on day 5 and discharged on day 7 with no neurological sequelae. To our knowledge, this case is the largest recorded overdose of amitriptyline to have survived to discharge. The importance of serum alkalinisation in the management of tricyclic antidepressant poisoning is highlighted.