The purpose of this study was to develop an alternative, improved and better tolerated injectable nimodipine nanosuspension compared with commercially available ethanol solution. In this study, nimodipine nanosuspension was prepared by high-pressure homogenization (HPH). The effects of the production parameters such as pressure, cycle numbers and crushing principles on the mean particle size, 99% diameter and polydispersity of the nanosuspension were investigated. Characterization of the product was performed by scanning electron microscope (SEM) and differential scanning calorimeter (DSC). The safety of the nimodipine nanosuspension was discussed with special attention to contamination by microparticles and the increase in saturation solubility C(s). Irritability study in rabbits showed that this formulation provided less local irritation and phlebitis risks than the commercial ethanol product, which represented a promising new drug formulation for intravenous therapy of subarachnoid hemorrhage (SAH)-related vasospasm.