Anastrozole, as the third generation aromatase inhibitor, is mainly used for the treatment of postmenopausal breast cancer. Its mechanism of action and drug interaction need to be focused. The following provides a detailed explanation from two aspects: the effects and drug interactions.

1. Effect of action

(1) Inhibition of estrogen synthesis: By selectively inhibiting aromatase, blocking the conversion of androgens to estrogen, and reducing estrogen levels in the body.

(2) Antitumor effect: it is used for postmenopausal breast cancer patients with hormone receptor positive, significantly reducing the risk of tumor recurrence.

(3) Therapeutic advantages: Compared to tamoxifen, anastrozole has a smaller impact on the endometrium and a lower incidence of thrombotic events.

2. Drug interactions

(1) Estrogen drugs: may antagonize the efficacy of anastrozole, and the combination of preparations containing estrogen is prohibited.

(2) CYP3A4 inducers such as rifampicin and carbamazepine may reduce the blood concentration of anastrozole and should be used with caution.

(3) CYP2C9 substrate: may affect the metabolism of drugs such as warfarin, and INR values need to be monitored to adjust dosage.

(4) Tamoxifen: Combination use may reduce the blood concentration of anastrozole and is not recommended for simultaneous use.

(5) Foods containing phytoestrogens, such as soy products, may interfere with drug efficacy. It is recommended to avoid excessive intake.

3. Medication precautions

(1) Taboo population

It is contraindicated for premenopausal women and those with severe liver function impairment. Pregnancy can cause fetal malformations, and menopausal status should be confirmed before medication.

(2) Drug interactions

Estrogen preparations can counteract drug effects and should be avoided in combination. CYP3A4 inducers may reduce the blood concentration of anastrozole.

(3) Adverse reaction management

Common symptoms such as hot flashes and joint pain are usually tolerable. Severe osteoporosis requires treatment with bisphosphonates. Regularly monitor bone density and blood lipids.