PURPOSE:

To investigate the effect of oral palmitoyl-ethanolamide (PEA) on intraocular pressure (IOP) in primary open angle glaucoma (POAG) and ocular hypertension (OH).

METHODS:

In a prospective, randomized, double-blind, crossover clinical trial, 42 patients with POAG or OH who were treated with timolol 0.5% and whose IOP was between 19 and 24 mm Hg received oral PEA (300-mg tablets twice a day) or placebo (PEA vehicle tablets twice a day) for 2 months (period 1), and, after a 2-month washout, received the other treatment for 1 month (period 2). IOP, best-corrected visual acuity, and visual field parameters were considered.

RESULTS:

After PEA treatment (mean baseline IOP, 21.6 ± 1.7 mm Hg), IOP was reduced by 3.2 ± 1.3 mm Hg at 1 month and by 3.5 ± 1.2 mm Hg (15.9% ± 5.1%) at 2 months (ANOVA, P < 0.001; both Tukey-Kramer, P < 0.01 vs. baseline); after placebo (mean baseline IOP, 21.5 ± 1.5 mm Hg), IOP was reduced by 0.4 ± 1.2 mm Hg at 1 month and by 0.3 ± 1.3 mm Hg at 2 months (t-test at both time points, P < 0.001 vs. PEA). No statistically significant vital signs, visual field, visual acuity changes, or adverse events were detected in either group.

CONCLUSIONS:

Systemic administration of PEA reduces IOP in patients with glaucoma and ocular hypertension. PEA could be a valuable tool for the treatment of glaucoma (http://www.umin.ac.jp/ctr/index/htm number, UMIN000002833).