Poisoning approach and drug overdoses

Decontamination and enhanced elimination

Reviewed Nov 2026·7 references
New· views rounded down, updated weekly

When to use activated charcoal, gastric lavage and whole bowel irrigation, and when to dialyse (EXTRIP).

Definition
Decontamination reduces absorption (activated charcoal, whole bowel irrigation, rarely lavage); enhanced elimination increases clearance (MDAC, urinary alkalinisation, extracorporeal treatment).

At the bedside

  1. 1

    Single-dose activated charcoal

    50 g within 1 h of a potentially toxic ingestion of an adsorbable drug (consider up to 2-4 h for large or sustained-release ingestions) if the airway is protected.

  2. 2

    Gastric lavage

    Not routine. Consider only within 60 min of a life-threatening ingestion with a protected airway and no effective alternative. Contraindicated for corrosives and hydrocarbons.

  3. 3

    Whole bowel irrigation

    PEG-electrolyte 1.5-2 L/h by NG until rectal effluent is clear: iron, lithium, sustained-release CCB/beta-blockers, body packers.

  4. 4

    Multiple-dose charcoal

    Life-threatening carbamazepine, dapsone, phenobarbital, quinine or theophylline: 50 g then 25 g every 4 h if bowel sounds present.

  5. 5

    Urinary alkalinisation

    Salicylate (and phenobarbital, chlorpropamide): bicarbonate to urine pH 7.5-8.0 with K replacement.

  6. 6

    Extracorporeal treatment (EXTRIP)

    Small, water-soluble, low protein-binding, low Vd toxins: lithium, salicylate, toxic alcohols, metformin (lactic acidosis), valproate, theophylline, carbamazepine, barbiturates. Intermittent HD preferred; CRRT if unstable.

Single-dose decontamination

Activated charcoal

Oral/NG
Dose
50 g (1 g/kg)
Worked example
70 kg: 50 g in 200-300 mL water; NG if intubated

MDAC

Activated charcoal

Oral/NG
Dose
50 g, then 25 g every 4 h

EXTRIP haemodialysis indications (selected)

ToxinRecommended when
LithiumImpaired kidney function and Li > 4.0 mEq/L, or decreased consciousness, seizures or life-threatening arrhythmia
SalicylateLevel > 100 mg/dL (> 90 with impaired kidneys), altered mental status, new hypoxaemia, or pH ≤ 7.20 despite treatment
MethanolComa, seizures, new visual loss, pH ≤ 7.15, persistent acidosis, anion gap > 24, or methanol > 70 mg/dL with fomepizole (> 60 with ethanol, > 50 without ADH blockade)

Summarised from EXTRIP workgroup statements; see full documents for 'suggested' indications.

Red flag · call your senior now
Salicylate poisoning with altered mental status or rising level: dialyse - and avoid intubation if possible (loss of respiratory compensation can be fatal); if intubated, match high minute ventilation.
Pitfall
Charcoal for alcohols, iron, lithium, acids, alkalis or hydrocarbons - they do not bind.
Pitfall
Routine gastric lavage in drowsy patients without airway protection: aspiration risk outweighs benefit.
Pearl
Lithium: chronic toxicity with modest levels can be more dangerous neurologically than acute ingestion with higher levels.

References

  1. 1

    Chyka PA, Seger D, Krenzelok EP, Vale JA; AACT/EAPCCT. Position paper: single-dose activated charcoal. Clin Toxicol 2005;43:61-87.

  2. 2

    Benson BE, Hoppu K, Troutman WG, et al. Position paper update: gastric lavage for gastrointestinal decontamination. Clin Toxicol 2013;51:140-6.

  3. 3

    Thanacoody R, Caravati EM, Troutman B, et al. Position paper update: whole bowel irrigation for gastrointestinal decontamination of overdose patients. Clin Toxicol 2015;53:5-12.

  4. 4

    American Academy of Clinical Toxicology; European Association of Poisons Centres and Clinical Toxicologists. Position statement and practice guidelines on the use of multi-dose activated charcoal in the treatment of acute poisoning. J Toxicol Clin Toxicol 1999;37:731-51.

  5. 5

    Decker BS, Goldfarb DS, Dargan PI, et al. Extracorporeal treatment for lithium poisoning: systematic review and recommendations from the EXTRIP workgroup. Clin J Am Soc Nephrol 2015;10:875-87.

  6. 6

    Juurlink DN, Gosselin S, Kielstein JT, et al. Extracorporeal treatment for salicylate poisoning: systematic review and recommendations from the EXTRIP workgroup. Ann Emerg Med 2015;66:165-81.

  7. 7

    Roberts DM, Yates C, Megarbane B, et al. Recommendations for the role of extracorporeal treatments in the management of acute methanol poisoning: a systematic review and consensus statement. Crit Care Med 2015;43:461-72.

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