To investigate ocular hypertensive effect of exogenous glucosamine in comparison to placebo in patients with osteoarthritis.

: In this double blind randomized clinical trial, 88 patients with osteoarthritis were included. Forty four patients were randomized into either glucosamine sulfate or placebo group. Comprehensive ophthalmologic exam including intraocular pressure (IOP) at baseline, month 1, and 3 were performed. Ocular response analyzer parameter including IOP Goldmann correlated, IOP cornea compensated, corneal hysteresis, and resistance factor were also checked at baseline and month 3.

The mean IOP at the time of presentation was 12.4 ± 2.7 mmHg in glucosamine and, 13 ± 2.8 mmHg in placebo group (P=0.329). At month one the corresponding values were 12.6 ± 2.4 and 12.9 ± 2.4 mmHg, (P=0.868), and at 3 months follow up were 13.5 ± 2.3, and 13 ± 2.7 mmHg respectively(P= 0.002). 34.1% in treatment and 12.5 % in placebo group had clinically significant (defined as ≥ 2mmHg) rise in IOP at final follow up (P=0.023). Mean age in those with significant rise in IOP was 66 years versus 57.7 in patients with less than 2 mmHg. (P=0.034). The baseline ORA Goldmann-correlated IOP, cornea-compensated IOP, corneal hysteresis, and resistant factor were 14.5 ± 2.7, 15.2 ± 2.7, 9.6 ± 1.4, and 9.5 ± 1.3 in treatment group; the corresponding values in placebo group were 15.3 ± 3.7, 15.5 ± 3.6, 10.5 ± 1.7, and 10.1 ± 2.2, respectively. (Respective P values: 0.276, 0.682, 0.008, 0.075)

Glucosamine supplement therapy causes statistically significant rise of IOP, which is more pronounced in elderly patients. Clinical implication of this finding needs further evaluation, but physicians should warn patients against liberal use of glucosamine, especially those affected by glaucoma.