As a CDK4/6 inhibitor, Abemaciclib is mainly used in the treatment of HR+/HER2 breast cancer. Its side effects involve the blood system, digestive system and other aspects. The following will explain from three aspects: handling of serious side effects, management of common adverse reactions, and special precautions.

1. Serious side effects requiring immediate medical attention

(1) Interstitial lung disease: Newly developed cough accompanied by difficulty breathing requires immediate discontinuation of medication and completion of chest CT examination.

(2) Serious infection: Prolonged high fever exceeding 38.5 ℃ or absolute neutrophil count<0.5 × 10 ^ 9/L requires urgent treatment.

(3) Venous thrombosis: Sudden swelling and pain in one limb require vascular ultrasound examination for deep venous thrombosis.

2. Common self relieving side effects

(1) Diarrhea: Supplement 1.5-2L of water daily. Mild diarrhea can be treated with oral montmorillonite powder.

(2) Neutropenia: Weekly monitoring of blood routine, 1-2 grade reduction can be temporarily observed.

(3) Fatigue: Ensure 7-8 hours of sleep per day and engage in low-intensity activities in different time periods.

3. Key preventive measures

(1) Blood monitoring: Complete blood cell count is measured before treatment and every 2 weeks until the second cycle.

(2) Liver and kidney function: Monitor ALT/AST and creatinine levels monthly, and adjust the dosage if there are abnormalities.

(3) Contraceptive requirements: Women of childbearing age should take contraceptive measures until 3 weeks after the last dose.

4. Precautions for special populations

(1) Liver dysfunction: Children Pugh Class C patients need to reduce their dosage to 100mg twice a day.

(2) Elderly patients: People aged 65 and above need to strengthen fall prevention and be alert to the side effects of dizziness.

(3) Pregnancy period: Animal studies have shown embryotoxicity, and pregnant women should avoid using it.