Background
Rocuronium (RN), an aminosteroidal non-depolarizing neuromuscular agent, and sugammadex (SG), a selective relaxant binding agent for RN, have been widely used in general anesthesia. In this study, we examined the effects of RN and SG on platelet aggregation, and expression of P-selectin (PS), an adhesion molecule on the surface of activated platelets.
Methods
Informed consent was given and the protocol was approved by the ethical committee. Venous blood was taken with 10 % volume of 3.8% tri-sodium citrate from healthy volunteers. Platelet-rich plasma (PRP) was prepared by centrifugation at 160 g for 10 min. 
(1) Aggregation study
PRP containing RN, SG, or RN + equimolar SG was incubated at 37 ̊C for 3 min. Adenosine diphospate (ADP)-induced aggregation was measured for 7 min as a change in light transmission using aggregometer.
(2) Flow cytometry (FCM) analysis for PS expression
PRP was stimulated by ADP with RN or RN + equimolar SG at room temperature for 30 min. PerCP-labeled anti-CD61 antibody and PE-labeled anti-CD62P (PS) antibody were co-incubated. PS expression levels were assessed by FCM.
All data were compared with one-way ANOVA, followed by Dunnett's post hoc test.
Results
RN suppressed ADP-induced platelet aggregation (>310 μg/ml) and PS expression (>3.1 μg/ml), but this effect was not abolished by equimolar SG (Fig. 1A, 1B and 2). SG (100 mg/ml) suppressed ADP-induced platelet aggregation (Fig. 1B).
Discussion
SG forms tight complexes at a 1:1 ratio with RN by encapsulating. Our results demonstrate that RN and RN-SG complex suppressed platelet functions within the usual therapeutic concentration range (< 10 μg/ml). Therefore, it might be possible that RN and RN-SG complex affect platelet functions in the clinical setting.
Conclusion
RN and RN-SG complex suppressed platelet functions. SG did not abolish this suppressive effects of RN.

Effects of rocuronium and sugammadex on human platelet functions in vitro