Alectinib, as a targeted drug for ALK positive non-small cell lung cancer, is contraindicated for individuals with severe liver function impairment and those who receive specific drug combination therapy. Additionally, it is important to avoid foods such as grapefruit that may interfere with metabolism. The following provides a detailed explanation from three aspects: taboo groups, dietary restrictions, and medication conditions.

1. Taboo population

(1) Liver dysfunction: It is contraindicated for patients with severe liver dysfunction (Child Pugh C grade), and should be reduced to 450mg bid for moderate impairment and closely monitored for liver enzymes.

(2) Pregnancy period: Based on animal teratogenic data, pregnant women are prohibited from using it. Before treatment, the pregnancy status should be confirmed, and women of childbearing age should take effective contraceptive measures.

(3) Breastfeeding period: Medication may be secreted into breast milk. Breastfeeding is prohibited during treatment and for one week after discontinuation of medication.

2. Forbidden foods

(1) Grapefruit/grapefruit juice: Contains strong CYP3A4 inhibitors, which may increase blood drug concentration and pose a risk of toxicity.

(2) St. John's wort: contains strong inducers of CYP3A4, which may reduce drug efficacy and should be avoided in combination.

(3) High fat diet: It is recommended to take on an empty stomach (1 hour before or 2 hours after meals), as fat may affect absorption.

3. Medication restrictions

(1) Drug interactions: Avoid using strong CYP3A4 inducers (such as rifampicin) or inhibitors (such as ketoconazole) in combination.

(2) Special monitoring: Regular checks on liver function, heart rate, and creatine kinase levels are required during treatment.

(3) Photoprotection: During medication, strict sun protection is required to avoid skin reactions caused by exposure to ultraviolet rays.