Potential Human Health Impacts and Medical Treatment of Acute Poisoning with Organophosphorus Pesticides (OPs): A Review

Organophosphate pesticides (OPs) are compounds that can be detected in human populations as a result of occupational or residential exposure. Despite their occurrence in considerably low levels in humans, their biological effects are hazardous since they interact with enzymes, proteins, receptors and transcription factors. The mechanism of OP poisoning involves inhibition of acetylcholinesterase (AChE) leading to inactivation of the enzyme which has an important role in neurotransmission. AChE inhibition results in the accumulation of acetylcholine at cholinergic receptor sites, producing continuous stimulation of cholinergic fibers throughout the nervous systems. Therefore, OP causes immunomodulatory effects, cancer, neurotoxicity and different infections. During more than five decades, pyridinium oximes have been developed as therapeutic agents used in the medical treatment of poisoning with OP. They act by reactivation of AChE inhibited by OP. However, they vary in their activity in poisoning with pesticides and warfare nerve agents and there is still no universal broad-spectrum oxime capable of protecting against all known OP. In this paper the available information related to health impacts and medical treatment of OP poisoning are reviewed and summarized, and the current recommendations are presented.