Alectinib, as a targeted drug for ALK positive non-small cell lung cancer, should be adjusted according to individual patient conditions in terms of usage and dosage. Special attention should be paid to safety risks when using it for special populations. The following provides a detailed explanation from three aspects: standard dosage, dosage adjustment, and medication for special populations.

1. Standard usage and dosage

(1) Recommended dose for adults

Take 600mg orally twice a day (with a 12 hour interval) with meals to improve bioavailability. Capsules should be swallowed whole and should not be opened or dissolved.

(2) Course management

Continue medication until disease progression or intolerable toxicity occurs. If the missed dose is more than 6 hours away from the next administration, it can be supplemented, otherwise the current dose will be skipped.

2. Dose adjustment plan

(1) Hepatotoxicity adjustment

Suspend medication when ALT/AST is greater than 5 times the upper limit of normal values, and reduce to 450mg bid after recovery to ≤ 3 times; The recurrence rate was further reduced to 300mgbid.

(2) Adjustment of interstitial lung disease

After diagnosis, permanent discontinuation of medication is required, and a systematic assessment of the severity of lung lesions and treatment with glucocorticoids is necessary.

(3) Bradycardia adjustment

Symptomatic bradycardia (<60 beats/minute with dizziness) should be temporarily discontinued and reduced after recovery; Permanently discontinue medication for life-threatening individuals.

3. Medication for special populations

(1) Pregnancy period

Animal studies have shown embryotoxicity and are contraindicated during pregnancy. Women of childbearing age need to confirm their pregnancy status before treatment, and use effective contraception during medication and one week after discontinuation.

(2) Lactation period

Medications may be secreted into breast milk, and breastfeeding is prohibited during the treatment period and within one week after the last administration.

(3) Liver dysfunction

Reduce the initial dose of Child Pugh Class C patients to 450mg bid; Mild to moderate damage does not require adjustment but requires strengthened monitoring.

(4) Renal insufficiency

Mild to moderate damage (eGFR ≥ 30mL/min) does not require adjustment; Due to severe damage or insufficient data from dialysis patients, caution should be exercised when using it.

(5) Pediatric patients

The safety and efficacy of using it for patients under 18 years old have not been established and is not recommended.

(6) Elderly patients

Patients aged 65 and above do not need to adjust their dosage, but close monitoring of liver function and cardiac toxicity is necessary.