Some problems of the pharmacologic treatment of haemorheological alterations of diabetes mellitus

Increased blood viscosity is present in diabetes mellitus: this may act as an accelerating factor in diabetic microangiopathy. The impaired rheological properties of diabetic blood are due to the increased plasma viscosity, enhanced red cell aggregation, reduced red cell deformability, circulating platelet aggregates, and seem strictly linked to the extent of blood glucose. Optimized metabolic control, particularly if obtained using insulin, has been shown to be successful in reversing many of the alterations present, but it must be achieved avoiding hypoglycemic events,which immediately worsen diabetic rheological alterations. Anyway, as any hypoglycemic treatment obtaining a good metabolic control does not reverse completely the pre-thrombotic state present in diabetics and as metabolic control is often difficult to be achieved steadily, some specific intervention must be undertaken. A part from isovolemic haemodilution, many drugs are proposed in this sense: some of them specifically act on plasma macroglobulins (fibrinolytic agents), on red cell deformability (pentoxifylline, calcium antagonists), on platelet aggregation (antiplatelet agents) and vessel walls (vasoactive drugs). Some seem to exert more than a single action, such as pentoxifylline, ticlopidine, calcium antagonists, suloctidil; it is proposable to prefer these drugs, if the case allows the choice. Other drugs (solfonylureas, mucopolysaccarides, lecitins) seem to be experimentally important, but have to be proven effective in vivo.