Efficacy of activated charcoal and magnesium citrate in the treatment of oral paraquat intoxication.

The binding capacity of activated charcoal for paraquat was evaluated in vitro and in vivo and compared with Fuller's earth. In vitro activated charcoal absorbs paraquat and is as effective as Fuller's earth. Activated charcoal's absorbing capacity for paraquat is increased when it is suspended in magnesium citrate and is maximal at pH 7.8. Paraquat (200 mg/kg) administered orally to male mice, followed 30 minutes later by activated charcoal, Fuller's earth (4 gm/kg), and magnesium citrate (0.01 cc/gm) resulted in a survival rate of 31% in the controls, 63% in the activated charcoal and Fuller's earth groups, and 69% in the magnesium citrate group (P values not significant). When activated charcoal was administered concomitantly with magnesium citrate, the survival rate was improved significantly to 94% (P less than 0.01). The efficacy and greater availability of activated charcoal and magnesium citrate make these materials the treatment of choice for gastrointestinal decontamination in oral paraquat poisoning.