What drugs interact with Anastrozole

Anastrozole dosage is mostly used to treat hormone receptor-positive breast cancer in postmenopausal women. Anastrozole, like any other prescription, can interact with other drugs, thereby reducing efficacy or increasing the risk of unwanted effects. The following medicines may interact with anastrozole:

Estrogen-containing medications: Because anastrozole acts by lowering estrogen levels, hormone replacement treatment or oral contraceptives may diminish its efficacy.

Tamoxifen: Tamoxifen is another drug used to treat breast cancer. It functions differently than anastrozole and may have antagonistic effects when combined.

Aromatase inhibitors: Taking additional aromatase inhibitors with anastrozole may raise the risk of side effects while not necessarily enhancing treatment outcomes.

Selective estrogen receptor modulators (SERMs): Anastrozole used to treat osteoporosis or prevent breast cancer, such as raloxifene or toremifene, may interact with anastrozole.

CYP3A4 inducers: Drugs that activate the CYP3A4 enzyme, such as rifampin, phenytoin, or St. John's Word, may increase the metabolism of anastrozole, lowering its effectiveness.