Patients treated with PPS long-term show significant impairment of choriocapillaris flow, study finds. Photo: Elmiron. Click image to enlarge.

Some systemic medications have unfortunate ocular side effects when taken long-term. Pentosan polysulfate sodium (PPS), an oral drug approved for the treatment of bladder pain due to interstitial cystitis, has been reported to put patients at greater risk for macular toxicity. Screening guidelines recommend yearly multimodal imaging for patients with large cumulative doses (>500g).

A recent study published in the American Journal of Ophthalmology reported that patients treated with PPS long-term (accumulating dosages beyond 1,000g) without retinal toxicity signs demonstrated significant impairment of choriocapillaris flow. This retrospective cohort study included 15 patients taking PPS for interstitial cystitis who had cumulative doses greater than 1,000g and 15 age-matched controls. All patients underwent multimodal imaging.

The mean cumulative dose of PPS was 1,974g over an average of 17.6 years. All patients had a visual acuity of 20/25 or better and normal fundus autofluorescence, OCT, multicolor, near-infrared reflectance and ultra-widefield fundus color and autofluorescence images. The researchers reported a significantly greater mean choriocapillaris flow deficit of 32.7% in the PPS group vs. 28.6% in the control group.

“The choroid may be the earliest target of ocular toxicity and may predate the development of retinal pigment epithelium (RPE) injury,” the researchers wrote in their paper. “RPE disruption may be the result of choriocapillaris impairment or primary PPS toxicity.” They recommended OCT-A and multimodal retinal imaging studies to determine whether flow deficit co-localizes with areas of functional loss, such as in the microperimetry, or areas of future RPE damage. Depending on the findings of future studies, the researchers noted that choriocapillaris flow deficit could potentially serve as a predictive screening tool for maculopathy and toxicity from PPS.