Amitraz, an underrecognized poison: A systematic review

BACKGROUND & OBJECTIVES: Amitraz is a member of formamidine family of pesticides. Poisoning from amitraz is underrecognized even in areas where it is widely available. It is frequently misdiagnosed as organophosphate poisoning. This systematic review provides information on the epidemiology, toxicokinetics, mechanisms of toxicity, clinical features, diagnosis and management of amitraz poisoning. METHODS: Medline and Embase databases were searched systematically (since inception to January 2014) for case reports, case series and original articles using the following search terms: ‘amitraz’, ‘poisoning’, ‘toxicity’, ‘intoxication’ and ‘overdose’. Articles published in a language other than English, abstracts and those not providing sufficient clinical information were excluded. RESULTS: The original search yielded 239 articles, of which 52 articles described human cases. After following the inclusion and exclusion criteria, 32 studies describing 310 cases (151 females, 175 children) of human poisoning with amitraz were included in this systematic review. The most commonly reported clinical features of amitraz poisoning were altered sensorium, miosis, hyperglycaemia, bradycardia, vomiting, respiratory failure, hypotension and hypothermia. Amitraz poisoning carried a good prognosis with only six reported deaths (case fatality rate, 1.9%). Nearly 20 and 11.9 per cent of the patients required mechanical ventilation and inotropic support, respectively. The role of decontamination methods, namely, gastric lavage and activated charcoal was unclear. INTERPRETATION & CONCLUSIONS: Our review shows that amitraz is an important agent for accidental or suicidal poisoning in both adults and children. It has a good prognosis with supportive management.