A 44-year-old lady was brought to ED by ambulance after her partner found her drowsy in her bedroom with multiple empty packets of Amitriptyline scattered around the bed. The ambulance crew found no other medications in the immediate vicinity. Her partner had last seen her two hours previously that evening and described a history of depression, previous overdoses and chronic alcohol excess. On arrival in ED, her airway was self-maintained but she had signs of vomitus around her mouth and smelled strongly of alcohol. Heart rate was 125, NIBP 92/38 and ECG showed sinus rhythm with prolonged PR and QRS intervals (240ms and 200ms, respectively). ABG showed a metabolic acidosis with lack of respiratory compensation, with hyperlactataemia (4.1). GCS was 9 (E2M5V2) although she appeared agitated with bilaterally dilated pupils. There was no external evidence of injury. The impression was of life-threatening Tricyclic Antidepressant (TCA) overdose within the last 2 hours along with alcohol ingestion.
What are the main features of a Tricyclic Antidepressant overdose? What treatment options are available?