In Charles River CD rats the
pesticide MITAC 20 EC (containing
amitraz and 75%
xylene) given orally at an LD80 dose caused toxicity featuring
hypothermia, reduced spontaneous activity, episodes of increased activity and minor signs of general debilitation. Recovery in survivors was complete within about 8 days.
Therapies including absorption retardants,
diuretics, reduction of urine pH, thermal support and treatment with
phentolamine or
nikethamide were given to groups showing these signs of
poisoning. None of the
therapies gave consistent evidence of benefit during acute
poisoning in terms of reduced intensity or duration of symptoms or reduced mortality. Comparison with animals given
amitraz alone suggested that the
hypothermia and the later phase of reduced spontaneous activity were attributable to the pharmacological effects of
amitraz. While the product was apparently more acutely toxic by the oral route than
xylene alone, the evidence was that
xylene caused the early signs of
poisoning. This work indicates that any case of
poisoning by ingestion of MITAC 20 EC should initially be treated for the
xylene exposure. There is no specific
therapy or
antidote for the subsequent possible pharmacological effects of
amitraz. Many other pesticides also contain high proportions of aromatic
solvents and the importance of the
solvent in cases of ingestion is seen to be applicable to a variety of pesticides as well as MITAC 20 EC.