Multicenter trial: Comparison of two different formulations and application systems of low-dose nasal midazolam for routine magnetic resonance imaging of claustrophobic patients

Purpose To prospectively assess and compare two formulations and methods of administration of low‐dose nasal midazolam for the treatment of claustrophobic patients undergoing magnetic resonance imaging (MRI) as part of a multicenter Phase III trial. Materials and Methods In all, 108 consecutive adult claustrophobic patients were randomly assigned to one of two treatment groups (multidose group: MDG, unit‐dose group: UDG). MDG encompassed 55 patients who received intranasally a 0.5% midazolam formulation into each nostril (total dose, 1.0 mg), whereas the 53 patients in UDG received a 1% midazolam formulation into only one nostril (total dose, 1.0 mg). This initial dose could be repeated once. Patient tolerance and anxiety were assessed using a questionnaire and a visual analog scale immediately before and after MRI. Image quality was evaluated using a five‐point scale. Results In all, 53/55 MR examinations (96%) with MDG and 52/53 (98%) with UDG were completed successfully. The dose of 1 mg had to be repeated significantly less often in UDG compared to MDG (4/53, 8% vs. 13/55, 24%; P = 0.003). The image quality of all MR examinations was rated good to excellent, and slightly better in UDG (P = 0.045). Conclusion Nasally applied low‐dose midazolam is a patient‐friendly solution to facilitate MRI of claustrophobicpatients. The nasal spray of UDG is superior to that of MDG with a necessity of additional dosing. J. Magn. Reson. Imaging 2008;28:866–872. © 2008 Wiley‐Liss, Inc.