Treatment of Paraquat Poisoning with Cyclophosphamide / Dexamethasone Combination : The First Two Years Experience at Siriraj Hospital

Abstract

While the mortality rate from paraquat is high, a proven treatment for paraquat poisoning is still lacked. In this article, we describe the outcome of the first two years of implementing a treatment protocol containing cyclophosphamide and dexamethasone for paraquat poisoning at Siriraj Hospital. Treatment group was studied by a retrospective review of cases at Siriraj Hospital with significant paraquat poisoning in 2002-2003. Significant ingestion means ingestion of 1gram total or 20 mg/kg or positive urine dithionite test for paraquat. AII patients with significant ingestion received treatments with a regimen consisting of enteral administration of a single dose of Fuller’s earth solution and a 14-day course of intravenous cyclophosphamide plus intravenous dexamethasone plus intravenously vitamin C. Survival rate was compared with historical controls that included searchable cases with significant paraquat poisonings admitted to Siriraj Hospital who were treated only with Fuller’s earth or Bentonite, vitamins B and C and supportive care. From January 2002 to November 2003, there were 6 cases of significant paraquat poisoning presented to Siriraj Hospital. The survival rate of treatment group is 83.3% as judged by presence without life-threatening signs at 4 weeks after the ingestion. Nine cases of significant paraquat poisoning were identified from Siriraj Hospital’s searchable medical records from 1994-1997 and were enrolled as controls. AII control cases died within 12 days, six from fulminant paraquat poisoning and the remaining from moderate to severe poisoning. The use of immunosuppressive agents known for its ability to treat inflammatory lung disease such as cyclophosphamide and dexamethasone presents a viable alternative to an otherwise serious and untreatable poisoning.