WikiTox

1. Overview

Decontamination refers to the techniques that reduce the exposure to a drug or toxin by reducing absorption. As with all interventions in clinical toxicology, the decision to proceed with decontamination should be based on a risk/benefit analysis.

Decontamination should always be a lower priority than patient resuscitation.

Induced emesis and gastric lavage are techniques that were used historically but are no longer recommended due to evidence of lower efficacy and higher risk than the other available decontamination techniques.

2. Activated Charcoal

Activated charcoal is the preferred method for gastrointestinal decontamination when indicated. It is a highly porous adsorbent with a large surface area which adsorbs most toxins. Most drugs are carbon-based and have side chains that may adhere via hydrogen bonding, ion-ion, or weak electrostatic forces.

Its effectiveness decreases with time. If given within 30 minutes of ingestion, charcoal may decrease the absorption of the ingested compound by up to 70%. This drops to 35% after 1 hour. The window of effectiveness is generally considered to be within 2 hours for an immediate release preparation and 4 hours for a modified/slow-release preparation. This window may be extended for agents which result in life-threatening toxicity or following massive ingestions where absorption is expected to be delayed.

Drugs poorly adsorbed by charcoal:

Hydrocarbons
Alcohols
Metals (e.g. Li+ and K+)
Corrosives

Dose:

Adult 💊: Activated charcoal 50 g or 1 g/kg PO or via NGT
Children 💊👶: Activated charcoal 1 g/kg PO or via NGT
💡In children charcoal may be added to ice cream to make it more palatable.

Potential complications:

Vomiting
Aspiration
Bowel obstruction

3. Whole Bowel Irrigation

Whole bowel irrigation (WBI) physically flushes substances from the gastrointestinal tract using large volumes of polyethylene glycol (PEG) solution until the effluent runs clear. Although effective, the practicalities of its implementation mean its use is largely limited to specific poisonings where activated charcoal alone is inadequate.

It is recommended early following poisoning and should not be used once a patient is unwell with established haemodynamic instability, as complications are more likely in this group.

Drugs amenable to WBI:

Sustained release preparations (e.g. mainly calcium channel blockers)
Medications not absorbed by charcoal (e.g. iron, lithium, potassium)
Toxins that can form pharmacobezoars (e.g. salicylates)
Body packers

Dose:

Adults 💊: PEG solution 1 L/h PO or via NGT
Children 💊👶: PEG solution 25 mL/kg/h PO or via NGT
WBI should be continued until the effluent runs clear – which usually occurs following approximately 5 L of fluid for adults.
An an antiemetic (e.g. ondansetron, metoclopramide) is often required.

Potential complications:

Normal anion gap metabolic acidosis
Aspiration
Distraction from resuscitative priorities

Example of procedure for adult WBI: NSW PIC Procedure Document for WBI

Decontamination

Table of Contents

Decontamination

1. Overview

2. Activated Charcoal

3. Whole Bowel Irrigation

4. References