Biological significance of cimetidine sulfoxide complexes with copper(II) and zinc(II) ions during cimetidine treatment

Abstract

Following a recent investigation into cimetidine interactions with copper(II) and zinc(II), the present work deals with the study of coordination equilibria relative to the main metabolite of this drug, i.e. cimetidine sulfoxide, with the same metal ions under physiological conditions. Computer simulations were run on the basis of the corresponding complex stability constants, in order to assess the extent to which cimetidine sulfoxide may affect copper(II) and zinc(II) plasma distributions during long term cimetidine therapy. No significant effect of this kind can be expected from cimetidine sulfoxide for plasma concentrations corresponding to usual therapeutic levels of the patent molecule, even for patients presenting with impaired renal function.