How glucosamine supplements may increase IOP
Glucosamine sulfate supplements widely used as an osteoarthritis treatment appear to increase IOP, researchers say.
The finding raises questions about whether the supplements could play a role in glaucoma, wrote H. Esfandiari of the University of Medical Sciences in Tehran, Iran and colleagues in the journal Eye.
Although the study did not have enough glaucoma patients to evaluate the effects of glucosamine in this population, “it’s a wise practice that ophthalmologists directly ask patients about its usage and carry out medication discontinuation trial[s] in uncontrolled cases,” the researchers wrote.
An amino monosccharide, glucosamine is an essential constituent of cartilage. Though evidence is lacking that it can improve symptoms of osteoarthritis, radiographic studies have shown that it slows joint space width loss. And since it appears to be safe, it is popular as a treatment.
However glucosamine is also abundant in corneal stroma and plays a role in the morphology and function of the trabecular meshwork. One small retrospective study showed an association between glucosamine supplement usage and intraocular pressure.
Other researchers have proposed that glucosamine could restore the extracellular matrix of cartilage or halt additional cartilage degradation. But “it’s no surprise” if changing glycosaminoglycans could lead to changes in IOP or IOP measurement, the authors wrote.
To investigate this finding further, Esfandiari and colleagues recruited 88 patients with osteoarthritis who attended a rheumatology clinic from July 2014 to March 2015.
They excluded patients with ophthalmological diseases that might affect the biomechanics of the cornea, including any history of ocular surgery, corneal scar and dystrophies.
They randomly assigned 44 patients to take 750 mg glucosamine three times a day for 3 months and 44 patients to take gelatinous capsules filled with sugar as a placebo on the same schedule.
Sixty-seven of the patients were female and 21 were male. Their mean age was 57.7 years. The mean IOP of the glucosamine group was 12.4 mmHg at baseline and 13.0 mm Hg in the placebo group, differences that were not statistically significant (P = 0.329).