Breast cancer is the most diagnosed type of cancer in women in Turkey and in the world. According to the World Health Organization data, the rate of newly diagnosed breast cancer was reported as 11.6% in 20181. Acute postoperative pain occurs in 40% of patients undergoing surgery for breast cancer2. In the early postoperative period, opioids are commonly used analgesics in the treatment of pain, but they have various side effects such as gastrointestinal, urinary and respiratory symptoms3. Non-opioid analgesics can be used to reduce opioid use and thus limit its side effects. Magnesium sulfate (MgSO4) is an N-Methyl D-Aspartate (NMDA) receptor antagonist that has been used for postoperative analgesia and reducing both the duration and intensity of pain by preventing central sensitization in response to peripheral painful stimulus4-9. The primary aim of this study is to investigate the postoperative analgesic efficacy of MgSO4 in patients who were scheduled for mastectomy with the diagnosis of breast cancer. The secondary aim of our study is to evaluate the changes in perioperative vital signs that may occur due to MgSO4.

Inclusion Criteria:

1. Female breast cancer patients scheduled for mastectomy and modified radical mastectomy
2. 18≥ years and
3. Patients with ASA score I-II

Exclusion Criteria:

1. The patient who refused the study
2. Drug allergy
3. Unregulated diabetes mellitus and hypertension
4. Cardiac failure with <45% ejection fraction
5. Renal failure (serum creatinine > 2 mg/dL)
6. Liver failure (blood transaminase values 2 fold higher than normal)
7. Glaucoma
8. Psychiatric or neurological disorders
9. Communication difficulties with patient
10. Calcium channel blockers or narcotic drugs uses before surgery