Effect of Clonidine as Adjuvant in Thoracic Paravertebral Block for Patients Undergoing Breast Cancer Surgery: A Prospective, Randomized, Placebo-controlled, Double-blind Study

BACKGROUND AND AIMS: Postoperative pain after breast cancer surgery is unavoidable. Thoracic paravertebral block (TPVB), a locoregional anesthetic technique, has been proven successful for postoperative pain management in different thoracic surgical procedures, such as thoracotomy, breast cancer surgeries. Clonidine, an adjuvant, in TPVB may enhance the quality and prolong the duration of analgesia. This prospective study was to evaluate the effectiveness of clonidine; administered with TPVB; in addition to conventional local anesthetic solution. MATERIALS AND METHODS: Fifty-two patients (25–55 years) scheduled for breast cancer surgery under general anesthesia were randomly divided into Group A (n = 26) receiving preoperative TPVB at T(3) with clonidine added to local anesthesia solution and Group B (n = 26) receiving identical TPVB with local anesthesia but without any adjuvant. This was followed by balanced general anesthesia. A visual analog scale was used to assess pain postoperatively up to 48 h. Meantime to administration of the first dose of rescue analgesic was noted. Total dose of fentanyl consumption, hemodynamic parameters, and side effects were all recorded for each patient. RESULTS: The dosage of fentanyl required in the intraoperative period was significantly lower in Group A. Mean time to administration of rescue analgesic was found to be significantly longer in clonidine group. Hemodynamics and side effects were quite comparable among two groups. CONCLUSION: Clonidine as adjuvant in TPVB provided profound analgesia for up to 48 h postoperatively for patients undergoing breast cancer surgery without any appreciable side effects.