The purpose of this study is to compare using FDA-approved bupivacaine (a numbing medicine), along with the usual medications for post-operative pain control to using the usual medications for postoperative pain control alone. The addition of bupivacaine to the surgical wound site with the usual pain medications could better manage your pain immediately after surgery and reduce the amount of opioid medications taken after surgery. This study will allow the researchers to know whether this different approach is better, the same, or worse than the usual approach.

Inclusion Criteria:

• Patients ≥ 18 years of age
• Patients undergoing unilateral mastectomy with or without SLNB or axillary dissection
• Patients scheduled for surgery at the JRSC or MSK Monmouth
• Previously enrolled patients > 6 months from contralateral mastectomy

Exclusion Criteria:

• Patients who are non-English speaking
• Patients having any immediate breast reconstructive procedure
• Patients are having bilateral mastectomy
• Patients who report a baseline pain score > 3, unrelated to a breast procedure
• Patients who take long acting opioid medication use
• Patients will be excluded if they are having their mastectomy performed with tumescence
• Patients weighing < 40kg as 20cc of bupivacaine 0.5% is greater than the maximum allowed dose
• Patients within 6 months of previous enrollment for surgery for contralateral mastectomy

Treatment assignments can be viewed only by the hospital pharmacists who are dispensing the study drugs.