Atta-Politou J.^*, Kolioliou M.^*, Havarioti M.^*, Koutselinis A.^*, Koupparis M.A.^**

^* Department of Forensic Medicine and Toxicology School of Medicine, University of Athens, Athens 115 27, Greece
^** Department of Chemistry, Laboratory of Analytical Chemistry University of Athens, Panepistimiopolis, Athens 157 71, Greece

In drug overdoses, treatment with activated charcoal (AC) is frequently used, due to its adsorptive properties in binding a variety of drugs and chemicals. Recently, whole bowel irrigation (WBI) with polyethylene glycol (PEG)-electrolytes lavage solution (PEG-ELS) has been used as an adjunctive gastrointestinal decontamination procedure for ingestions of toxins not well adsorbed to AC and for toxins with a delayed absorption phase, although well adsorbed to AC. While it has been suggested that a combined approach using AC and WBI could theoretically enhance the efficacy of both modalities, this improvement remains largely speculative, since data demonstrating its clinical advantage in routine overdose treatment are lacking. Fluoxetine, a selective serotonin uptake inhibitor, is one of the most frequently prescribed antidepressants. One of the risks involved with fluoxetine medication is the high attempted suicide rate of the population group for whom it is prescribed. Fluoxetine is well adsorbed onto AC. Thi in vitro investigation was undertaken to study: a) the effect of PEG, as well as PEG-ELS, upon the adsorption of fluoxetine onto AC at gastric and intestinal pH, and b) whether the order of PEG-ELS addition would have an effect upon adsorption of fluoxetine onto AC. The results of this study revealed that the amount of fluoxetine adsorbed to AC was dramatically decreased at gastric and intestinal pH by the presence of PEG or PEG-ELS added either concurrently or sequentially to AC. It can be concluded that in cases of fluoxetine overdoses administration of AC is indicated while a combined approach using AC and WBI with PEG-ELS is controindicated since a significant desorption of the drug from AC can be caused.