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.