Clinical toxicology: part II. Diagnosis and management of uncommon poisonings.
OBJECTIVE
To review the diagnosis and management of drug overdose and poisonings in a two-part presentation.


METHODS
A review of articles reported on drug overdose and poisonings.


RESULTS
In patients who attempt suicide it is usual for the overdose to be a therapeutic agent, although in the severely mentally disturbed patient the agent may be an unusual poison. As with any overdose, the most important aspects in the management is the maintenance of the patient's airway, ventilation and circulation, while the toxin is metabolised and excreted. Adsorbents, gastric lavage and haemodialysis or continuous renal replacement therapy and specific antidotes may be beneficial in individual cases. The diagnosis and management of uncommon poisonings, including pesticides and herbicides (e.g. organophosphates, carbamates, paraquat, chlorophenoxy herbicides), carbon monoxide, cyanide, strychnine, halogenated hydrocarbons, elemental poisons (e.g. iron, arsenic, lead, mercury, selenium, barium, thallium, lithium, sodium, rubidium, cesium), alkaloids (e.g. mushroom, aconite, conium) and cantharidin poisoning along with the miscellaneous poisonings of quinine, chloroquine, isoniazid, thyroxine, cytotoxic agents (e.g. azothioprine, 6-mercaptopurine, colchicine, methotrexate) are discussed in the second part of this presentation on clinical toxicology.


CONCLUSIONS
In the critically ill patient who has taken an overdose of a non therapeutic agent, while activated charcoal, continuous renal replacement therapy and specific antidotes may be of benefit, maintenance of the patient's airway, ventilation and circulation still remain the most important aspects of management.
Department of Critical Care Medicine, Flinders Medical Centre, Adelaide, South Australia. lindsay.worthley@flinders.edu.au
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Worthley