The use of Tucatinib should focus on preventing diarrhea, hepatotoxicity, and reproductive risks. The dosage should be adjusted according to toxic reactions, and attention should be paid to drug interactions. Individualized medication plans are needed for special populations.

1. Serious Adverse Reaction Management

(1) Diarrhea

The median onset time of the first diarrhea is 12 days after medication, and immediate treatment and investigation of the cause are required. Suspend medication for grade 3 diarrhea and reduce dosage after recovery; Level 4 requires permanent discontinuation of medication.

(2) Hepatotoxicity

Monitor liver function before medication and every 3 weeks. ALT/AST>5 × ULN or bilirubin>3 × ULN should be temporarily discontinued, and for patients with liver failure, medication should be permanently discontinued.

2. Dose adjustment standard

According to the grading of toxicity reactions, the dosage can be reduced to 250mg per dose for the first time, and then further reduced to 200mg → 150mg → permanent discontinuation. The initial dose for patients with severe liver dysfunction should be 200mg/time.

3. Drug interactions

Avoid using strong CYP3A inducers and moderate CYP2C8 inducers in combination. When using potent CYP2C8 inhibitors, it is necessary to reduce the dosage. Use CYP3A and P-gp substrate drugs with caution.

4. Medication for special populations

(1) Pregnancy and lactation period

Pregnant women are prohibited from using contraception, and women of childbearing age should use contraception for at least 1 week after the last dose. Breastfeeding is prohibited within 7 days after taking medication during lactation.

(2) Liver dysfunction

Reduce the dose to 200mg/time twice daily for Child Pugh Class C patients. During the treatment period, it is necessary to strengthen liver function monitoring.

5. Medication operation matters

The recommended dosage is 300mg twice a day, with no restrictions on meals. Missing medication does not require supplementation, please take the medication according to the original plan next time. Drug overdose requires immediate medical attention.

6. Fertility related risks

Animal experiments have shown embryotoxicity, and efficient contraceptive measures should be taken during medication. Male patient partners also need to use synchronized contraception.