Amitraz poisoning: A case report of an unusual pesticide poisoning in Sri Lanka and literature review.

BACKGROUND: Amitraz is a pesticide used worldwide on animals and in agriculture. It contains triazapentadiene, which is a centrally acting alpha-2 adrenergic agonist. Amitraz poisoning is fairly uncommon in humans and occurs via oral, dermal or inhalational routes. Only a limited number of case reports of human intoxication have been published and most of them are of accidental ingestion by children. CASE PRESENTATION: A twenty-year-old Sri Lankan female presented following self-ingestion of 20 ml of amitraz resulting in 37.8 mg/ kg of amitraz poisoning. She lost consciousness after 20 min of ingestion, developed bradycardia and hypotension, which needed intravenous fluid resuscitation and dobutamine. Gastric lavage was performed. Her bradycardia persisted for 36 h and she was drowsy for 48 h. She did not develop respiratory depression, convulsions or hypothermia and the urine output was normal. Arterial blood gas revealed mild respiratory alkalosis. She recovered fully within 48 h and was discharged on day 3. CONCLUSION: The clinical manifestations of amitraz (impaired consciousness, drowsiness, vomiting, disorientation, miosis, mydriasis, hypotension, bradycardia, respiratory depression, hypothermia, generalized seizures, hyperglycemia and glycosuria) can be explained by the agonist action of amitraz on α1 and α2 receptors. Management of amitraz poisoning is still considered to be supportive and symptomatic with monitoring of nervous system, cardiovascular and respiratory systems. Activated charcoal may still be considered for treatment and the place for gastric lavage is controversial. Atropine is effective for symptomatic bradycardia and inotropic support is needed for hypotension that does not respond to fluid resuscitation. Diazepam or Lorazepam is used for convulsions and some patients may require intubation and ICU care. Several α2 adrenergic antagonists like yohimbine have been tried on animals, which have successfully reversed the effects of amitraz. Since the majority of amitraz poisoning cases are due to accidental ingestion, manufactures, regulatory authorities and national poisons control centers have a significant role to play in minimizing its occurrence.

A randomised, assessor blind, parallel group comparative efficacy trial of three products for the treatment of head lice in children--melaleuca oil and lavender oil, pyrethrins and piperonyl butoxide, and a "suffocation" product.

BACKGROUND: There are many different types of pediculicides available OTC in Australia. In this study we compare the efficacy and safety of three topical pediculicides: a pediculicide containing melaleuca oil (tea tree oil) and lavender oil (TTO/LO); a head lice "suffocation" product; and a product containing pyrethrins and piperonyl butoxide (P/PB). METHOD: This study was a randomised, assessor-blind, comparative, parallel study of 123 subjects with live head lice. The head lice products were applied according to the manufacturer's instructions (the TTO/LO product and the "suffocation" product were applied three times at weekly intervals according to manufacturers instructions (on Day 0, Day 7 and Day 14) and the P/PB product was applied twice according to manufacturers instructions (on Day 0 and Day 7)). The presence or absence of live lice one day following the last treatment was determined. RESULTS: The percentage of subjects who were louse-free one day after the last treatment with the product containing tea tree oil and lavender oil (41/42; 97.6%) and the head lice "suffocation" product (40/41, 97.6%) was significantly higher compared to the percentage of subjects who were louse-free one day after the last treatment with the product containing pyrethrins and piperonyl butoxide (10/40, 25.0%; adj. p < 0.0001). CONCLUSION: The high efficacy of the TTO/LO product and the head lice "suffocation" product offers an alternative to the pyrethrins-based product. TRIAL REGISTRATION: The study was entered into the Australian/New Zealand Clinical Trial Registry, ACTRN12610000179033.

Hepatic xenobiotic metabolism of cylindrospermopsin in vivo in the mouse.

Cylindrospermopsin (CYN) is a hepatotoxin isolated from the blue-green alga Cylindrospermopsis raciborskii. The role of both glutathione (GSH) and the cytochrome P450 enzyme system (P450) in the mechanism of toxicity of CYN has been previously investigated in in vitro systems. We have investigated the role of GSH and P450 in vivo in mice. Mice pre-treated with buthionine sulphoximine and diethyl maleate to deplete hepatic GSH prior to dosing with 0.2mg/kg CYN showed a seven-day survival rate of 5/13 while the control group rate was 9/14. Dosing mice with 0.2mg/kg CYN produced a small decrease in hepatic GSH with a characteristic rebound effect at 24h. The magnitude of this effect is however small and combined with the non-significant difference in survival rates after GSH depletion suggest depletion of GSH by CYN could not be a primary mechanism for CYN toxicity. Conversely, pre-treatment with piperonyl butoxide, a P450 inhibitor, protected mice against CYN toxicity giving a survival rate of 10/10 compared with 4/10 in the control group (p < 0.05 Chi squared) and was protective at doses up to 0.8 mg/kg, suggesting activation of CYN by P450 is of primary importance in the mechanism of action.

Morphometric and immunohistochemical studies on atrophic changes in lympho-hematopoietic organs of rats treated with piperonyl butoxide or subjected to dietary restriction.

Changes observed in lympho-hematopoietic organs in rats given piperonyl butoxide may be attributable either to direct toxic effects or to undernutrition. Male F344 rats were therefore fed diet containing 2.5% piperonyl butoxide or subjected to a 64% restriction of food intake for 2 weeks. Marked inhibition of body weight gain, decreased white blood cell count, depletion of T/B lymphocytes in lymphoid tissues, hypoplasia of the bone marrow, and decreased proliferating cell nuclear antigen (PCNA) labeling indices in these tissues were seen in both dietary restriction and 2.5% piperonyl butoxide groups. The depletion of T lymphocytes in the thymus and spleen was stronger in the 2.5% piperonyl butoxide group, as indicated by PCNA labeling indices and image analysis of T lymphocyte areas of the spleen, however, the toxicological profile observed for the chemically treated group was essentially the same as for animals on the restricted diet. These results suggest that the lympho-hematopoietic findings in rats receiving 2.5% piperonyl butoxide are probably due to undernutrition resulting from a reduced food intake.

[Synergism of selected pesticides. 1. Acute oral toxicity in combined administration]. / Untersuchungen zum Koergismus ausgewählter Pestizide 1. Mitt. Akute orale Toxizität bei kombinierter applikation.

Comparative studies with male rats were performed to investigate the coergism of single oral doses of selected pesticides, the comparison being based on the lethal effects observed. The quantitative analysis of the dose-mortality relationship and the determination of the coergistic index evidenced a slight increase of the lethal effect with lindane-phosmet and lindane-carbaryl combinations. The combined administration of lindane and ethylenethiourea resulted in an additive lethal effect.