Study Comparing Dynastat and Parestat Pain Relief Medications for Patients After Breast Surgery

The goal of this clinical trial is to learn if generic parecoxib (Parestat) works as well as the original drug (Dynastat) for treating pain after breast surgery. It will also learn about the safety of both drugs. The main questions it aims to answer are: * Does Parestat provide pain relief that is not inferior to the pain relief provided by Dynastat? * What medical problems (adverse events) do participants have when taking Parestat compared to Dynastat? Researchers will compare Parestat to Dynastat to see if the generic version also works to treat postoperative pain. Participants will: * Be randomly assigned to receive either Dynastat or Parestat during their surgery. * Have their pain level assessed using the Visual Analog Scale (VAS) upon arrival in the recovery bay, 6 and 24 hours after surgery. * Be monitored for common side effects like nausea, vomiting, and changes in blood pressure for 24 hours.