[The pharmacology of gold compounds]

Parenterally administered gold compounds have been used for decades for treatment of rheumatoid arthritis. The new gold compound triethylphosphine gold (auranofin) can be partially absorbed in the gut following oral administration due to its higher lipophilic nature. This is probably also the main cause for the differences in kinetic properties versus the parenteral gold compounds. Following administration of auranofin, there are lower concentrations of gold in blood and organs; 95% of the gold is excreted in feces whereas 70% of gold, following gold sodium thiomalate, is excreted in the urine. These differences have consequences for the mode of adverse reactions. A common property of all gold compounds, however, is the relative distribution in organs. The highest concentrations of gold were found in the reticuloendothelial system, in liver, kidney and spleen, followed by joints. The mode of action of gold compounds is still unexplained. They inhibit some types of experimental inflammation and the activity of various cells involved in inflammatory processes. In some cases auranofin exerts a higher influence. Following incorporation of gold in lysosomes, the impairment of macrophage function appears to be most important. This effect probably influences (indirectly) the immune system since macrophages interact with T- and B-lymphocytes. The significance of these findings for the therapeutic effect of gold compounds is, however, not known. The rate of undesirable effects of gold compounds is very high requiring exact supervision during chrysotherapy. Mucosal and cutaneous reactions are very frequent, followed by proteinuria, diarrhea and thrombocytopenia. Bone marrow aplasia is most serious but relatively rare.(ABSTRACT TRUNCATED AT 250 WORDS)