Intranasal Scopolamine for Motion Sickness

INTRODUCTION: Rapid onset, noninjection methods are required to provide "as needed"therapy for motion sickness. Intranasal scopolamine (IN SCOP) is attractive because it can be fast acting and work when gastric motility is slowed. Intranasal administration can provide a time to maximal concentration (T-max) of drugs (e.g., naloxone and midazolam) of 30 min or less. We evaluated the efficacy, pharmacodynamics, and pharmacokinetics of IN SCOP in a placebo-controlled, randomized, double-blind, dose-ranging study, and compared pharmacokinetic outcomes against other published results. METHODS: There were 18 healthy adult volunteers (10 M, 8F) who received placebo, low dose (0.2 mg), and high dose (0.4 mg) IN SCOP intranasally using a pump device and a gel formulation. Participants rode in an off-vertical axis rotation (OVAR) chair 1.25 h after dose administration and completed neurocognitive tests to evaluate secondary drug impacts. Pharmacokinetics (PK) and pharmacodynamics (PD) were assessed in eight subjects. PK data were compared to results from previously published studies. RESULTS: Low and high dose IN SCOP increased chair time significantly compared to placebo. No significant sleepiness or cognitive impairment was seen, likely due to the small sample size. T-max was long for both dosages (High dose 75.0 +/- 49.4 min, Low dose 61.9 +/- 37.1 min), compared to other intranasally administered drugs and some previous studies with IN SCOP. Average T-max was not superior to previously published values for dose-matched (0.4-0.5 mg), orally-delivered SCOP. DISCUSSION: IN SCOP has potential as a rapid administration route for relieving MS symptoms, but more work is needed to identify optimal intranasal formulation and dispensing methods.