Abemaciclib, as a CDK4/6 inhibitor, requires attention to blood toxicity, liver and kidney function monitoring, embryo fetal toxicity, and drug interactions. Regular evaluations of blood routine and liver function are necessary. Contraceptive measures should be strictly implemented in the reproductive age population, and the risk of infection and diarrhea should be monitored.

1. Hematological toxicity

(1) Common neutropenia requires monitoring of blood routine before treatment and every 2 weeks. Medication should be suspended or reduced for grade 3-4 neutropenia.

(2) May cause anemia or thrombocytopenia, in severe cases requiring blood transfusion support. Treatment should be interrupted when hemoglobin<8g/dL or platelets<50 × 10 ⁹/L.

2. Liver and kidney function monitoring

(1) ALT/AST testing should be conducted before treatment and on the first day of the cycle. If there is grade 2 or above liver injury, medication should be suspended until recovery is achieved.

(2) Patients with moderate to severe liver function impairment should adjust the dosage, and use with caution for severe renal function impairment (CLcr<30mL/min).

3. Embryo fetal toxicity

(1) Pregnant women of childbearing age need to undergo pregnancy testing before medication, and take effective contraceptive measures during treatment and 3 weeks after the last dose.

(2) Animal experiments have shown teratogenicity. Male patients' spouses need contraception during the same period, and breastfeeding is prohibited.

4. Infection and Diarrhea Management

(1) May increase the risk of infection, and symptoms such as fever require immediate assessment and anti infective treatment.

(2) The incidence of diarrhea is high, and antidiarrheal medication should be used as soon as it appears for the first time. If it is grade 3 or above, medication should be suspended and fluid should be replenished.

5. Drug interactions

(1) Avoid using strong CYP3A4 inducers (such as rifampicin) in combination, as it may reduce efficacy; Inhibitors (such as ketoconazole) need to be reduced in dosage.

(2) The combination with BCRP/P-gp substrates (such as rosuvastatin) may increase the toxicity of the latter, and adverse reactions need to be monitored.

6. Medication for special populations

(1) Elderly patients are more prone to blood toxicity and need to be monitored more closely; The safety of pediatric patients has not been established.

(2) Individuals with QT prolongation risk, electrolyte imbalance, or a history of heart disease should undergo regular electrocardiogram examinations.