Toxicokinetics of Paraquat in Humans

Abstract

<jats:p> 1 The toxicokinetics of paraquat were studied in 18 cases of acute human poisoning using a specific radioimmunoassay. Plasma paraquat concentration exhibited a mean distribution half-life ( t<jats:sub>½</jats:sub> α) of 5 h and a mean elimination half-life ( t<jats:sub>½</jats:sub> β) of 84 h. Cardiovascular collapse supervened early during the course of the intoxication and was associated with the distribution phase. Death related to pulmonary fibrosis occurred late and was associated with the elimination phase. </jats:p><jats:p> 2 Pharmacokinetic analysis of urine paraquat excretion confirmed the biphasic decline of paraquat. Moreover, renal paraquat and creatinine clearances were not correlated but renal paraquat clearance was never higher than the renal creatinine clearance. </jats:p><jats:p> 3 Tissue paraquat distribution was ubiquitous with an apparent volume of distribution ranging from 1.2 to 1.6 l/kg. Muscle could represent an important reservoir explaining the long persistence of paraquat in plasma and urine for several weeks or months after poisoning. </jats:p>

Proteomic analysis of changes in protein expression in serum from animals exposed to paraquat

“…Clinical features of PQ ingestion depend on the quantity ingested and the time elapsed from ingestion. Upon ingestion, PQ is rapidly absorbed, distributed to various tissues, and within 12-24 h most of the absorbed PQ is secreted through urine (4,5). Within a few days, patients may develop severe lung damage such as fibrosis, the main cause of mortality with PQ toxicity.…”

CT imaging as a prognostic indicator for patients with pulmonary injury from acute paraquat poisoning

“…PQ primarily enters the body through the digestive tract, where it is mainly absorbed in the jejunum (nearly 17% absorption) and excreted by renal excretion. Because plasma concentrations of PQ peak within 2 h of exposure, treatment must be administered immediately [8]. Surviving patients may also develop severe side effects, such as tissue injury along the gastrointestinal tract, shock, coma, nosebleeds, seizures and stomach pains [1].…”

Therapeutic effects of smecta or smectite powder on rats with paraquat toxication

“…The peak plasma concentration of patients occurs within 2–4 hours after ingestion of PQ and then decreases. [35] The initial decrease, which is called the distribution phase, is faster and has a half life of about 5 hours, while the volume of distribution is about 1.2–1.6 L/kg. The half life in the subsequent elimination phase is about 84 hours.…”