Tryptophan Supplementation and Postoperative Delirium—A Randomized Controlled Trial

What this study found

Postoperative L-tryptophan did not reduce the incidence or duration of delirium, including excitatory delirium. Delirium occurred in 40% of the L-tryptophan group versus 37% of placebo, and excitatory delirium occurred in 17% versus 9%, respectively. Mean delirium duration was 2.9 days with L-tryptophan and 2.4 days with placebo; mean excitatory delirium duration was 3.3 versus 3.1 days. Tryptophan biomarker levels increased postoperatively in the active group, but this did not translate into a clinical benefit.

Study & population

Randomized, double-blind, placebo-controlled trial in older adults aged 60 years and older undergoing major elective surgery requiring postoperative ICU admission.

Intervention

Postoperative oral L-tryptophan was given at 1 g three times per day, starting the evening after surgery, for nine doses or until discharge from the surgical ICU.

Key limitation

Single-center study in a mostly male veteran population, which limits generalizability.

View full study detailsView sourceOpen PDF