Review of Pindone

EXECUTIVE SUMMARY
Pindone is a first generation anticoagulant used to control rabbits in areas where the alternative rabbit poison, sodium fluoroacetate (1080), is either impractical or unsuitable. These include urban and semi- rural areas including hobby farms, golf courses and horticultural areas. Pindone inhibits the manufacture of blood clotting factors (prothrombin), leading to a reduction in the clotting ability of the blood. Large single exposures can result in acute poisoning, however, pindone is highly effective when given as a series of smaller doses over a period of 4 to 12 days. This causes anticoagulant poisoning with a long latent period between ingestion and mortality, resulting in death due to internal haemorrhaging. One of the advantages of pindone is the availability of an antidote in the case of accidental poisonings.

There are currently two chemical forms of pindone; pindone acid (a mixture of keto and enol forms) and pindone sodium (sodium salt of pindone), which are used to prepare baits for rabbit control in Australia. The main difference between the two is that pindone acid has low water solubility while the sodium salt is soluble in water. Based on the differences in water solubility it has been proposed, but not yet proven, that baits based on pindone acid will remain active for a longer period than baits based on pindone sodium. Acid and salt forms of pindone can be regarded as essentially equivalent in toxicity once ingested as gastric acidity liberates the “free acid” from the salt. Both forms of pindone break down to the same end-product in the field and have the same non-target impacts to fauna.