Poisoning by an Unknown Herbicide or Pesticide

All poisonings involving pesticides or herbicides should be assumed to be serious until proven otherwise (these products were not developed with therapeutic intentions).

An accurate diagnosis is essential as there are a few specific antidotes. Common poisonings from this group are:

• organophosphates
• carbamates
• pyrethrins
• glyphosate
• hormonal herbicides
• boron containing ant killers
• white oil (paraffin oil)
• Ratsak and other rodenticides

In addition some people (farmers and licensed pest exterminators) may have access to the following extremely toxic substances:

• Arsenic
• Paraquat
• Organochlorines
• Strychnine
• 1080 (sodium monofluoroacetate)

Specific history that should be sought includes retrieving any chemicals (even unlabelled substances) to aid identification. The bottle may often have the manufacturer's name and an identifying number from which the product may be identified. The National Poisons Register, held by all poisons information centres in Australia, may be used to identify products from either brand names or description of products. For example, ant killers as well as most fungicides and a small number of insecticides are sold as powders, rodenticides as pellets, and most insecticides/herbicides as concentrated liquids.

All patients should have the following tests done urgently:

• plasma cholinesterase
• electrolytes, bicarbonate
• chest X-ray