Answer
The most frequently reported treatment-related side effect of Opatanol (olopatadine hydrochloride) in clinical studies was eye pain, with an overall incidence of 0.7%.
Sources for this answer
- OPATANOL 1mg/ml eye drops solutionNovartis Pharmaceuticals UK Ltd · emc · SmPC §4.8 Undesirable effects · Version 12Document updated
Sources checked