Drug Overdose

Question 1

A 24-year-old female is admitted to the emergency department with a suspected drug overdose. You are asked to review her due to a drop in her conscious level.

What is your initial management for this patient?

Answer 1

• Review the patient immediately.
• Assess the patient for risk to clinical staff with a “hands-of” handover,
  to consider any concerns that may necessitate the use of personal
  protective equipment.
• Carry out an ABCDE assessment focusing on the patient’s airway,
  which may need urgent intervention if impaired consciousness has
  led to the inability to maintain adequate ventilation.
• Ensure a thorough history is taken from the paramedics and/or
  a friend/relative to ascertain the potential ingested substances.
• Use specific and supportive treatment as indicated and refer to the relevant teams once she is stable e.g. medicine, intensive care, and psychiatry.

Question 2

Based on the collateral history, it is estimated that she has ingested ~14 units of alcohol, an unknown quantity of diazepam and 16g of paracetamol.

How do you proceed?

Answer 2

Initial treatment:
* Initial management of this patient depends on the findings from the ABCDE assessment but should include:
- Stabilisation including considering a definitive airway if appropriate.
- Examination to assess for alternative pathology (including trauma)
causing an altered conscious level.
- Treatment of specific symptoms e.g. vomiting.
- Treatment of the paracetamol overdose according to local
guidelines.

Question 3

Based on the collateral history, it is estimated that she has ingested ~14 units of alcohol, an unknown quantity of diazepam and 16g of paracetamol.

How do you proceed…continued?

Answer 3

Investigations:
* Continuous bedside monitoring of this patient in a safe location (e.g. the emergency department resuscitation bay) is essential, as well as initial baseline blood tests to include:
- Full blood count.
- Urea and electrolytes.
- Liver function tests.
- Clotting.
- Lactate and blood gas.
- Paracetamol and salicylate levels (4 hours post ingestion).
- Full screen to rule out overdose of other agents. Consider retention of toxicology samples for medico-legal purposes.

Further management:
* Full medical and drug history.
* Escalation to intensive care if appropriate.

Question 4

What is the role of activated charcoal in drug overdoses?

Answer 4

• Activated charcoal can be used in cases of drug overdose as it binds to agents and prevents them from being absorbed in the gastrointestinal tract.
• It should be given within an hour of drug ingestion but can be considered with drugs that are of slow or modified release formations, including the use of additional doses.
• Care should be taken in patients with reduced conscious levels as there is a risk of pulmonary aspiration.

Question 5

How would you treat the paracetamol overdose?

Answer 5

• Supportive therapy is key.
• Specific treatment is with an intravenous infusion of N-acetylcysteine
  dosed according to weight. Local guidelines dictate timing and further investigations; however, it should be noted that this patient has ingested a significant amount of paracetamol and is at high risk for acute liver failure.

Question 6

How would you manage the diazepam overdose?

Answer 6

• Treatment for benzodiazepine overdose is largely supportive.
• The specific antidote is flumazenil, a benzodiazepine receptor antagonist, but administration of this is not recommended initially due to the potential for harmful side effects including arrhythmias and seizures.

Question 7

What are the criteria for consideration of a liver transplant due to acute liver failure secondary to a paracetamol overdose?

Answer 7

The King’s College Hospital criteria are:
* pH<7.3.
* Grade 3/4 encephalopathy.
* Serum creatinine >300 μmol/L.
* INR >6.5 (or prothrombin time >100 seconds).