Robenacoxib is typically dosed once a day. After oral administration, peak blood concentrations are reached in about 30 minutes, meaning it has a fairly quick onset of action. Full effects have typically worn off for both the injectable and the oral form after a 24-hour period.
If you feel your cat is still uncomfortable or painful before 24 hours has elapsed after the last dose, especially after a surgical procedure, giving more robenacoxib would not be appropriate. In this case, it is best to contact your veterinarian to see if an additional pain medication may be advised.