Simulations of magnetorheological fluids are performed with different models for the hydrodynamic drag law. The shear stress predictions from two coupled discrete element - smoothed particle hydrodynamics models with different drag laws are compared to pure discrete element simulations for a wide range of Mason numbers. The discrete element model has a higher computational efficiency but the treatment of the hydrodynamic drag force involves some rough approximations. Based on the results of this study, a criterion is proposed for the applicability of the pure discrete element model in the simulation of sheared magnetorheological suspensions. (C) 2015 Elsevier B.V. All rights reserved.