Finasteride, as a 5 α - reductase inhibitor, is mainly used to treat male hair loss and benign prostatic hyperplasia. Its contraindications involve individuals with special physiological conditions and allergic constitutions. During medication, specific foods and alcohol should be avoided, and dosage limits and monitoring requirements should be strictly followed.

1. Taboo population

(1) Pregnant women and women of childbearing age: Medications can be absorbed through the skin and affect the development of male fetal genitalia. Pregnant women or women who may become pregnant should avoid contact with broken pills.

(2) Children: Not approved for pediatric patients, lacking safety and efficacy data for individuals under 18 years old.

(3) Patients with severe liver function impairment: Use with caution as it may affect drug metabolism.

(4) For individuals allergic to finasteride: contraindicated.

2. Taboo foods and substances

(1) Grapefruit and its products: may inhibit CYP3A4 enzyme and increase blood drug concentration.

(2) Alcohol: may exacerbate adverse reactions such as dizziness.

(3) High fat diet: It is recommended to take it on an empty stomach or with a light diet to avoid affecting absorption.

3. Restrictive conditions

(1) Dose limit: Treatment for hair loss should not exceed 1mg per day, and treatment for prostate hyperplasia should not exceed 5mg per day.

(2) Observation period of therapeutic effect: Continuous medication for more than 3 months is required to evaluate the effect, and the best therapeutic effect should be achieved for at least 12 months.

(3) Regular monitoring: During medication, it is necessary to regularly check PSA levels (prostate cancer screening indicators) and liver function.

(4) Discontinuation reaction: The therapeutic effect may be reversed within 12 months after discontinuation, and new hair may gradually fall out.