[Drugs acting on erythrocytes]

The deformability of red blood cells depends not only on acidosis and hypoxia, but also on hemoglobin concentration, presence of Heinz bodies, characteristics of red blood cells, membrane fluidity, surface/volume ratio, ATP levels and water concentration of red blood cells. The two most important consequences deriving from the change in one or more of the above mentioned factors are a reduction of red blood cell flexibility and an increase of red blood cell aggregation. We have examined various drugs which directly or indirectly interfere with one or more of the previously listed factors. There are also drugs considered useful in improving the altered red blood cell deformability and/or in reducing the formation of red blood cell aggregates; among these are some xanthine derivatives (pentoxifylline) and some calcium-entry blockers used as antihistamines (cinnarizine and flunarizine). These considerations need an experimental verification based on in vitro and in vivo or ex vivo studies.