巴拉刈是1,1’-dimethyl-4,4’-bipyridinium dichloride 的商品名，一般是藍綠色溶液，在國內廣泛的被農民用來去除雜草，屬於速效型雙吡啶基除草劑(bipyridyl herbicide)。巴拉刈經人體快速吸收後，肺臟和腎臟是產生傷害的主要器官。巴拉刈會在肺臟產生毒性的活性氧自由基，對肺部造成嚴重傷害，大部份無法恢復，最後因呼吸衰竭而死亡。腎臟是主要的排泄器官，巴拉刈在12-24 小時內由腎臟排除的過程中，巴拉刈會被高度濃縮，在24 小時內造成急性腎小管壞死。腎臟受到損傷後，會使體內毒物排除變慢，更進一步造成毒性破壞。食入巴拉刈的症狀除局部口腔、喉部及腸胃道會產生發炎及潰瘍外，對受損的皮膚、眼睛也會發生嚴重的發炎反應。全身的中毒症狀包括了肺臟、腎臟、肝臟傷害，也會有內分泌、心血管、神經系統等多重器官損傷。巴拉刈中毒造成高死亡率的原因在於目前缺乏廣為接受的治療準則、沒有解毒劑以及沒有特殊藥物可以有效地減緩毒性的傷害。本篇綜論的目的在於討論巴拉刈的毒性機制、中毒的症狀和檢視近年來在治療巴拉刈中毒的醫學證據及研究進展。

Paraquat is the trade name for 1,1’-dimethyl-4,4’-bipyridinium dichloride, a bipyridyl herbicide. It is a rapidacting herbicide widely used by farmers. While it was rapidly absorbed by gastrointestinal tract, the major target organs were the lung and kidney. In the lung, paraquat reacts to generate high levels of toxic oxygen species resulting in severe lung injury, mostly irreversible, which leads to respiratory distress and death. The kidney is key excretory organ. During 12-24 hours, the paraquat is highly concentrated and acute tubular necrosis can develop within 24 hours. The slower detoxication process can lead to further toxicity after renal failure. The symptoms of intoxication include local inflammation and ulcers in oral cavity, pharynx, eyes, damaged skin and gastrointestinal tract. The systemic effects include severe damages to multiple systems: the lung, kidney, liver, endocrine system, cardiovascular system and neurological system. The high mortality of paraquat intoxication results from its specific toxicity, no antidote, no known chelators and lack of effective therapies to reverse fulminant toxic destructions. Our purpose is to discuss about the toxicokinetics, clinical features, prognosis and review the latest medical progress in the treatment of paraquat intoxication.