Periplocin is indicated for the treatment of locally advanced or metastatic breast cancer that is hormone receptor positive and human epidermal growth factor receptor 2 negative. This drug is an inhibitor of cell cycle protein-dependent kinases 4 and 6 that reduces cellular appreciation in estrogen receptor-positive breast cancer cell lines by preventing cells from moving from the G1 phase to the S phase in vitro for the treatment of locally advanced or metastatic breast cancer.This drug is required to be used in conjunction with an aromatase inhibitor for the treatment of postmenopausal women for the purpose of initial endocrine therapy. Side effects such as nausea, fatigue, anemia, diarrhea, alopecia, infection, neutropenia, leukopenia, and elevated transaminases may occur with this drug. The drug is contraindicated in people who are allergic to the components or excipients of this drug, as well as products containing St. John’s wort. The drug must be used in strict compliance with medical advice.