Thu21October0907PM 8

A 32-year-old woman with a history of severe depression is admitted to the medical admissions unit.

She has been found unconscious in a locked room at home, having not been seen for six hours. There is a strong smell of alcohol. Her Glasgow coma score is 7/15 and both pupils are dilated. Her pulse rate is 110 beats per minute and blood pressure 110/70 mmHg. The patient develops a grand mal seizure and is intubated and ventilated.

ECG shows sinus tachycardia with prolonged QRS complexes and a significantly prolonged QTc interval. Arterial blood gas analysis reveals metabolic acidosis.

What is the most appropriate initial treatment?

(Please select 1 option)

Sodium bicarbonate Correct

Administration of activated charcoal orally

Intravenous amiodarone

Intralipid infusion

Continuous veno-venous haemodiafiltration (CVVHDF)

Explanation

Overdose of tricyclic antidepressants can readily be fatal and is often associated with seizures and arrhythmias. Treatment is broadly supportive. If signs of a severe overdose are present, administration of sodium bicarbonate can treat arrhythmias and prevent their development if the QTc interval is prolonged.

The patient has not been seen for six hours and the time of the overdose is unknown. So, although activated charcoal within the first hour can reduce absorption, in this case evidence of severe toxicity already exists and sodium bicarbonate is a more appropriate option.

Tricyclic antidepressants are not cleared by continuous veno-venous haemodiafiltration (CVVHDF). This may, however, be required to assist in clearing the metabolic acidosis if bicarbonate fails.

Intralipid has been described in severe cases but is recommended on Toxbase as a later treatment for toxicity refractory to other measures.

Antiarrythmic drugs are best avoided where possible.

Answer Statistics

1

83%

2

3%

3

1%

4

3%

5

14%

Times answered: 242