Comparing Oral and Sublingual Ketamine Lozenges as Rescue Analgesics in Adults with Acute Pain

Inpatients with acute pain rated as 5 or more on numerical rating scales (NRS) started on ketamine lozenges were recruited after informed consent. The primary aim is to compare clinical efficacy of oral and sublingual ketamine lozenges. Patients were randomised to receive ketamine 50mg lozenge sublingually with placebo lozenge orally or ketamine 50mg lozenge orally with placebo lozenge sublingually on each treatment day. A pharmacist did the randomisation, enabling researchers administering the treatment over two days to remain blinded. Participants were asked to swallow first lozenge and then suck on second lozenge until it has dissolved completely on both days. Participants were asked the question if the lozenge has dissolved completely on each treatment day. Time to first effect and meaningful effects were documented by research staff. Participants were then given a timer and data collection sheet. Participants were advised on how to score their pain at rest and at set intervals during the trial. Pain scores were self recorded half hourly for first two hours, then hourly for next two hours. Side effects were recorded for each treatment period. Patients satisfaction and global impression of change were recorded at the end of each treatment periods by research staff.