Haemorheological Effects of a 5-HT 2 Receptor Antagonist (Ketanserin)

Abstract

The haemorheological effect of a specific 5-hydroxy-tryptamine antagonist (ketanserin) was studied in 15 patients with severe ischaemic disease, given a continuous infusion for 7 days. The results were compared to a placebo infusion in 10 similar patients. The whole blood viscosity decreased significantly by 11–21% depending on the shear rate applied (0.7, 2.4 and 95 s⁻¹) during active treatment. This viscosity decrease can be attributed to haemodilution, since the blood viscosity data corrected to a standard haematocrit did not show any significant change. The haemodilution may have been partly due to the very marked effect of ketanserin on physical properties of white cells, manifested by a 53% decrease in the number of “clogging particles” 1n the blood. The red cell deformability index, determined as the transit time of red cells relative to the suspending medium, was also improved by ketanserin.