Current applications of plasmapheresis in clinical toxicology

The clinical applications of plasmapheresis are rapidly increasing in number and scope. This trend is also observed in the application of plasmapheresis as a method of detoxification in clinical toxicology. Because of a lack of large controlled series, the rationale for using plasmapheresis must be confirmed in each type of intoxication by evidence of effective clearance, as well as by high plasma protein binding and a low volume of distribution of the toxic substance. Plasmapheresis is used mostly to treat phalloid mushroom intoxications. In this potentially fatal intoxication, for which there is no antidote, plasmapheresis is at least as effective as haemoperfusion in reducing mortality from as high as 30-50% with conventional therapy to <20%. In our series of 28 patients treated with plasmapheresis, mortality was 17.8%. In our experience, plasmaphe-resis is also very effective in the treatment of life-threatening intoxications with tricyclic (amitriptyline) and 4-cyclic (maprotyline) antidepressants. We confirmed a 63% reduction in the plasma level of amitriptyline in one patient after single plasmapheresis. Other drugs such as L-thyroxine, verapamil, diltiazem and carbamazepime are also removed effectively by plasmapheresis, as are theophylline and heavy metals (mercury and vanadate). Phosphoroorganic substances are not removed effectively. We measured the plasma concentrations of dimethoate in two patients with this intoxication and did not find clinically significant clearance with plasmapheresis.