Abstract:
Sibutramine is used in the treatment of obesity due to its ability to influence feelings of hunger and satiety by
inhibiting the re-uptake of serotonin and noradrenalin in the central nervous system (CNS). Sibutramine use
has been associated with numerous adverse events in particular cardiovascular complications possibly due to
the formation of thrombi. This ultrastructural descriptive study investigated the effect of sibutramine on blood
coagulation, specifically the effect on morphology of platelets and fibrin networks using scanning electron
microscopy. Male Sprague–Dawley rats treated with either a recommended therapeutic dose [low dosage
1.32 mg/kg] or a toxicological higher dose [high dosage 13.2 mg/kg] of sibutramine for 28 days were used and
compared to control animals. Blood samples were collected and plasma smears were prepared for platelet
evaluation. Following the addition of thrombin to the plasma samples, the morphology of the fibrin clots was
evaluated. Platelet evaluation by scanning electron microscopy revealed morphology typical of a prothrombotic
state with a characteristic excessive platelet activation in both low-dose (LD) and high-dose (HD) rats. The
fibrin clots of sibutramine-treated rats, LD and HD revealed fused thick fibers with thin fibers forming a netlike
structure over the thick fibers which differ considerably from the organized structure of the control animals.
It can be concluded that sibutramine alters the ultrastructure of platelets and fibrin networks creating a
prothrombotic state.
