There was a marginal increase in elasticity with 5 μg/mL of the drug and this became significant (P < 0.05) with the 10 μg/mL dose. Thereafter, gradual nonsignificant decreases were observed with the 20 and 40 μg/mL doses. A similar trend was observed for the control group. The elasticity values for the HbSS subjects at native hematocrit were significantly (P < 0.05) less when compared with the corresponding concentrations for the HbAA controls. This was reversed at a corrected hematocrit of 45%.
Conclusion:
The result of this study shows that sildenafil caused an initial increase in erythrocyte membraneelasticity in both HbSS and HbAA subjects, and this later decreased with increasing concentration of the drug possibly due to the dual effect of cyclic adenosine monophosphate (cAMP).