Efficacy, Tolerability, and Safety of Concentrated Intranasal Midazolam Spray as Emergency Medication in Epilepsy Patients During Video-EEG Monitoring

Background An efficient, well tolerated, and safe emergency treatment with a rapid onset of action is needed to prevent seizure clusters and to terminate prolonged seizures and status epilepticus. Objectives This study aimed to examine the efficacy, tolerability, and safety of intranasal midazolam (in-MDZ) spray in clinical practice. Methods In this retrospective, multicenter observational study, we evaluated all patients with peri-ictal application of in-MDZ during video-EEG monitoring at the epilepsy centers in Frankfurt and Marburg between 2 014 and 2017. For every patient, we analyzed the recurrence of any seizure or generalized tonic-clonic seizures after index seizures with and without in-MDZ administration. Treatment-emergent adverse events (TEAEs) were also evaluated. Results In-MDZ was used in 243 patients with epilepsy (mean age 35.5 years; range 5-76 years; 46.5% female) for treatment of 459 seizures. A median dose of in-MDZ 5 mg (i.e., two puffs; range 2.5-15 mg) was administered within a median time from EEG seizure onset until in-MDZ application of 1.18 min [interquartile range (IQR) 1.27], while median time from clinical seizure onset until in-MDZ administration was 1.08 min (IQR 1.19). In-MDZ was given within 1 min after EEG seizure onset in 171 seizures. An intraindividual comparison of seizures with and without application of in-MDZ was feasible in 171 patients, demonstrating that in-MDZ reduced the occurrence of any (Cox proportional-hazard model p < 0.001) and generalized tonic-clonic seizure (Cox proportional-hazard model p = 0.0167) over a period of 24 h. The seizure-free timespan was doubled from a median of 5.0 h in controls to a median of 10.67 h after in-MDZ administration. We additionally clustered in-MDZ administrations for the 119 patients who received in-MDZ more than once, comparing them with the index cases without in-MDZ. Even when considering subsequent seizures with in-MDZ administration, a patient receiving in-MDZ is still half as likely to incur another seizure in the upcoming 24 h as compared with when the same patient does not receive in-MDZ (hazard ratio 0.50; 95% CI 0.42-0.60; p < 0.01). In-MDZ was well tolerated without major adverse events. The most common side effects were irritation of the nasal mucosa [37 cases (8.1%)], prolonged sedation [26 cases (5.7%)], and nausea and vomiting [12 cases (2.6%)]. A decline in oxygen saturation was measured after 78 seizures (17%). Conclusion We conclude that in-MDZ is a safe and efficient treatment option to prevent short-term recurrence of seizures. In-MDZ can be administered very quickly by trained staff within 1-2 min after seizure onset. No major cardiocirculatory or respiratory adverse events were observed.