Study outcomes were compared during the pre-intervention period (four months before the intervention), transition period (seven months after the intervention), and postintervention period (four months after the transition period). [A] Errors bars show 95% confidence intervals for each mean. The mean quantity of opioid prescribed during the post-intervention period was significantly reduced compared to the pre-intervention period for simple mastectomy or wide local excision for melanoma (30 vs. 16 tablets of 5 mg oxycodone, P < 0.001) and lumpectomy or breast biopsy (24 vs. 10 tablets of 5 mg oxycodone, P < 0.001). [B] Opioid prescription refills during the post-intervention period were not significantly different compared to the pre-intervention period for simple mastectomy or wide local excision for melanoma (13% vs. 14%, P = 0.8) and lumpectomy or breast biopsy (4% vs. 5%, P = 0.7).