Is another drug-induced maculopathy afoot? While Plaquenil toxicity is now well known and patients on the drug are carefully monitored, such certainty is lacking about the effects of pentosan polysulfate sodium (PPS) on eye health. Two recent studies looking at the association between macular disease and PPS—an interstitial cystitis drug—use may have raised more questions than they answered. Each arrived at a different conclusion, with one finding that PPS exposure was associated with a new maculopathy diagnosis after seven years and the other suggesting no link between the two.^1,2

The first retrospective cohort study compared PPS users with matched controls at five and seven years. Results indicated that 0.3% and 0.6% of PPS patients progressed to atypical maculopathy compared with 0.2% and 0.3% of control patients at the five- and seven-year marks, respectively. The researchers added that 3.4% and 5.4% of PPS patients developed atypical maculopathy and age-related macular degeneration (AMD) compared with 2.9% and 4.1% of control patients at five and seven years, respectively. They noted that there was no significant association at five years, while PPS users had significantly increased odds of having atypical maculopathy and AMD at seven years.¹

The second evaluated 227,325 cystitis patients. The most common maculopathies this team found were wet AMD (1.5%), drusen (0.8%), dry AMD (0.3%), toxic maculopathy (0.1%) and hereditary dystrophy (0.04%). Their data show that the percentage of patients who filled a PPS prescription and were later diagnosed with maculopathy (2.37%) was similar to the percentage of patients who did not fill a prescription (2.77%). They did not find a significant association between PPS exposure and any type of maculopathy, nor was there a dose-dependent relationship between PPS exposure and maculopathy diagnosis.²

Clearly, more research is necessary to explain these divergent findings and clarify the association, if any exists, between PPS use and macular disease.