Comparison of morphine and clonidine as adjuvants in paravertebral block

General anesthesia (GA) has been considered as the gold standard for breast cancer surgery. The problem of postoperative pain as well as the high incidence of nausea and vomiting has led to the search for a better modality for pain management with fewer side effects. In the last few years, paravertebral block (PVB) has gained immense popularity either in combination with GA or by itself for the anesthetic management of patients undergoing breast surgery.