Objectives: 

Selective Serotonin Re-uptake Inhibitors (SSRI), widely used in major depression, are reported to exert both positive and negative cardiovascular effects. This study aimed to investigate how blood viscosity, an important risk factor for cardiovascular diseases, is affected by two different SSRIs.

Materials: 

35 male SD rats were used in 5 groups: control, acute and chronic sertraline (SE) and fluvoxamine (FL). SSRIs were given 10 mg/kg via gavage for 4 days (acute) or 21 days (chronic). Hematocrit, plasma viscosity (PV), erythrocyte deformability (ED) and erythrocyte aggregation (EA) parameters such as aggregation half time (t½), aggregation amplitude (AMP), and aggregation index (AI) were assessed. ED and EA were measured by LORCA, PV by cone-plate viscometer. Data were tested with Kruskal-Wallis and Mann-Whitney-U tests.

Results: 

Acute-FL group had lower ED (0.585±0.011) (P>0.05). No difference was observed between control (0.596±0.004) and acute-SE (0.597±0.006), chronic-SE (0.596±0.006), chronic-FL (0.598±0.002) groups.

All SSRI groups had higher AI. AI of the control was 43.4±8.4 whereas values for acute-SE, acute-FL, chronic-SE and chronic-FL groups were 48.9±3.1, 44.2±8.7, 46.6±4.5 and 50.8±3.3 respectively.

t½ of the control was 5.8±2.4 whereas values for acute-SE, acute-FL, chronic-SE and chronic-FL groups were 4.1±0.6, 5.3±2.2, 4.5±0.9 and 3.7±0.7 respectively.

AMP of the control was 14.6±1.4 whereas values for acute-SE, acute-FL(P<0.05), chronic-SE (P<0.05) and chronic-FL groups were 12.9±0.8, 11.8±1.5, 11.9±0.8 and 13.2±1.4 respectively.

These results imply that SE and FL augment AI by decreasing t½.

Conclusions: 

Augmentation of EA and attenuation of ED raise blood viscosity. This study shows that some SSRIs may have untoward effects on blood viscosity. Further studies are required to test all SSRIs and their possible untoward effects also on humans as well as studies that reveal the mechanism of this effect and its relevance to cardiovascular risk.