Results from a double blinded, randomized, placebo-controlled, feasibility trial of melatonin for the treatment of delirium in older medical inpatients

BACKGROUND: Delirium is common in elderly inpatients, causing distress, cognitive decline, and death. No known intervention improves the course of delirium; current treatments are symptomatic, and limited by lack of efficacy and adverse effects. There is an urgent need to find an effective treatment for delirium.

AIMS: Determine the feasibility of a trial of oral Melatonin 5mg nightly for 5 nights for the treatment of delirium in older medical inpatients, and determine the participants required to demonstrate a clinically and statistically significant decrease in severity of delirium in older medical inpatients treated with Melatonin.

METHODS: This was a double blinded, randomized controlled trial in general internal medicine units of a tertiary teaching hospital. Older (≥70 years) inpatients with Confusion Assessment Method (CAM) positive hyperactive or mixed delirium were suitable for inclusion. Subjects received Melatonin 5mg oral nightly for 5 nights or matching placebo. The primary outcome was the Memorial Delirium Assessment Scale (MDAS) administered daily.

RESULTS: No adverse effects occurred due to Melatonin. In the treatment group, the mean change in MDAS from baseline during treatment period was 2.5±5.0 points, in the placebo group, 2.1±4.1 points, a non-significant difference. A power calculation accounting for drop-out (31.0%), suggests 120 participants would be required to demonstrate with 90% power that melatonin 5mg reduces the severity of delirium by 3 points or more on MDAS.

CONCLUSIONS: A trial of the hypothesis that 5mg Melatonin nightly for 5 nights reduces delirium severity in older medical inpatients would require 120 patients, and is feasible. This article is protected by copyright. All rights reserved.