EFFECT OF ACTIVATED-CHARCOAL AND ATROPINE ON ABSORPTION AND OR EXSORPTION OF ORGANOPHOSPHORUS COMPOUNDS IN RATS/

Effects of activated charcoal and atropine for the removal of organoph osphorus compounds, which remain in the gastrointestinal tract or have already been absorbed into the systemic circulation, were investigate d in rats. Activated charcoal extensively adsorbed the organophosphate s fenitrothion, tolclofos methyl, piperophos and salithion, and its im mediate administration after oral ingestion of fenitrothion remarkably reduced serum fenitrothion levels, but had no effect on the serum lev els of the compound which had been absorbed from the gastrointestinal tract. Thus, all of the organophosphorus compounds were poorly exsorbe d (0.002-0.39% of the dose in 120 min) from the blood into the intesti nal lumen probably due to their extensive protein binding and large di stribution volumes. Atropine inhibited absorption of fenitrothion in t he perfusion in-situ and also delayed the absorption of the compound i n-vivo, but had no significant effect on exsorption of fenitrothion. T he serum fenitrothion levels on treatment with both atropine and charc oal significantly decreased compared with those of the control. We con clude that, oral activated charcoal will not be able to enhance the el imination of organophosphorus compounds which have already been absorb ed into the systemic circulation, but constitute a useful method for t he removal of the compounds remaining in the gastrointestinal tract be cause of its excellent adsorptive capacity.