Glucosamine Supplements May Increase Intraocular Pressure

Jan 24, 2017

Over-the-counter treatment for joint pain commonly prescribed by physicians may increase intraocular pressure leading to glaucoma risk, new study suggests.

An over-the-counter treatment for joint pain commonly prescribed by rheumatologists and other physicians may increase intraocular pressure, a new study suggests.

The treatment, glucosamine sulfate taken in supplements, could increase the risk of glaucoma, according to H. Esfandiari of the University of Medical Sciences, Iran, and colleagues in the journal Eye. They called on ophthalmologists to “directly ask patients about its usage and carry out medication discontinuation trial[s] in uncontrolled cases” of glaucoma.

Glucosamine, an amino monosccharide, is an essential constituent of cartilage. Despite little evidence that it can improve symptoms of osteoarthritis, radiographic studies have shown that it slows joint space width loss. It is popular as a treatment, partly because of its reputation for safety.

But glucosamine is also abundant in corneal stroma. And it 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.

Intrigued, Dr. 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. 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).  [[{"type":"media","view_mode":"media_crop","fid":"56017","attributes":{"alt":"(Glaucoma ©ARZTSAMUI/Shutterstock.com)","class":"media-image media-image-right","id":"media_crop_481779618655","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"7032","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"font-size: 13.008px; float: right;","title":"(Glaucoma ©ARZTSAMUI/Shutterstock.com)","typeof":"foaf:Image"}}]]

At month 1, IOP rose to 12.6 mmHg in the glucosamine group and fell to 12.9 mmHg in the placebo group. The differences were still not statistically significant (P = 0.868).

At month 3, IOP rose to 13.5 mmHg in the glucosamine group and 13.0 mm Hg in the placebo group. At that point, the difference reach statistical significance (P = 0.023).

In the glucosamine group, 34% of patients had an increase of more than 2 mm HG compared to 23.5% of patients in the placebo group.

The mean age in those with increases of 2 mm Hg IOP or more was 66 years, compared to 57.7 years in patients who had increases of less than 2 mm Hg. But the risk of ocular hypertension was not associated with diabetes mellitus, cardiovascular disease or gender.

“The results of this study show that while glucosamine causes statistically significant increase in IOP in patients with [osteoarthritis], corneal biomechanics remain unchanged within 3 months of glucosamine supplement therapy,” the authors conclude.

Their results suggest that glucosamine supplementation could be “pathological” in the trabecular meshwork after 3 months, they write.

 

 

References:

H Esfandiari, M Pakravan, Z Zakeri, et. al. "Effect of glucosamine on intraocular pressure: A randomized clinical trial," Eye. Oct. 21, 2016. DOI:10.1038/eye.2016.221

Karel Pavelka, MD, PhD; Jindriska Gatterová, MD; Marta Olejarová, MD; et al. "Glucosamine Sulfate Use and Delay of Progression of Knee Osteoarthritis. A 3-Year, Randomized, Placebo-Controlled, Double-blind Study," JAMA Internal Medicine. Oct. 14, 2002. DOI:10.1001/archinte.162.18.2113

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