Zoledronic Acid Associated Anterior Uveitis – A Single Institutional Experience on Management and the Rechallenge

PURPOSE: Zoledronic acid (ZA), an intravenous bisphosphonate widely used in oncology for managing malignancy-related bone disease, is commonly associated with acute phase reactions and renal toxicity. However, ocular inflammation, particularly acute anterior uveitis (AAU), is an uncommon and underrecognized adverse effect. This study aimed to characterize the clinical features, management strategies, outcomes, and rechallenge feasibility of ZA-induced anterior uveitis (ZAIU) in patients treated at a tertiary cancer centre. METHODS: We performed a retrospective review of patients who developed AAU following ZA infusion between March 2023 and May 2025. Demographic details, underlying cancer diagnoses, timing of symptom onset, laterality, ophthalmologic findings, treatment received, and subsequent bone-modifying therapy decisions were collected from medical records. Drug causality was assessed using the Naranjo algorithm. Institutional Review Board approval was obtained. RESULTS: Six patients (five women, one man; median age 56 years) developed ocular symptoms within 24-72 hours of their first ZA dose. All presented with eye pain, redness, and photophobia, and slit-lamp examination confirmed anterior uveitis. Each case was classified as a probable adverse drug reaction (Naranjo score 6). Prompt treatment with topical corticosteroids, with or without cycloplegics, resulted in complete symptom resolution and no lasting visual deficits. Four patients were successfully rechallenged with ZA or an alternative bisphosphonate without recurrence. One patient switched to denosumab, and one declined further therapy. . CONCLUSION: ZAIU is an uncommon but reversible complication. Early recognition and timely treatment lead to excellent outcomes, and cautious rechallenge appears feasible in selected patients.