About nepafenacnsaid,anti inflammatory eye preparationmechanism of action of nepafenacnepafenac is a prodrug. after penetrating the cornea, nepafenac undergoes rapid bioactivation to amfenac, which is a potent nsaid that uniformly inhibits the cox1 and cox2 activity.indications for nepafenactreatment of pain and inflammation associated with cataract surgery.typical dosage for nepafenacnepafenac is usually given as 1 drop in the affected eye 3 times per day, starting 1 day before cataract surgery. do not use nepafenac ophthalmic for longer than 14 days after your surgery unless the doctor tells you to. wash the hands before using the eye drops.