Poisoning — whether intentional (overdose), accidental, or occupational — is a common reason for ICU admission. The approach must always begin with ABCDE resuscitation, because the systemic effects of toxins can cause life-threatening airway compromise, respiratory depression, cardiovascular collapse, and seizures. Identifying the specific agent is important but secondary to stabilisation — the immediate priority is keeping the patient alive while the toxicological diagnosis is established.

The history is invaluable when available: what was taken, how much, when, and by what route. Collateral history from family, the ambulance crew, and the GP is often essential. Physical examination looking for toxidromes — the characteristic clusters of signs associated with specific drug classes — can narrow the diagnosis rapidly even when the history is incomplete or unreliable.