Attention should be paid to the risks of diarrhea, hepatotoxicity, and drug interactions when using Tucatinib. Diarrhea may cause severe dehydration or kidney damage, requiring timely cessation of diarrhea and adjustment of medication; Liver toxicity requires regular monitoring of liver function; At the same time, it is necessary to avoid using CYP3A/CYP2C8 inducers/inhibitors and specific substrates in combination to enhance toxicity or reduce efficacy.

Diarrhea management

The median time of first onset of diarrhea is 12 days after medication, which may be accompanied by dehydration, hypotension, or acute kidney injury. If symptoms appear, immediate treatment should be given to stop diarrhea, and medication should be suspended, reduced, or permanently discontinued depending on the severity. The median relief time is about 8 days, and close monitoring of electrolytes and renal function is required.

2 Liver toxicity monitoring

May cause liver injury with ALT/AST>5 times the normal upper limit or bilirubin>3 times the normal upper limit. Liver function should be tested before medication and every 3 weeks. If abnormalities occur, the dosage should be adjusted or the medication should be stopped. Patients with severe liver dysfunction should follow medical advice to reduce their dosage.

3 drug interactions

(1) Avoid using strong CYP3A inducers or moderate CYP2C8 inducers in combination; (2) The use of potent CYP2C8 inhibitors should be reduced; (3) Be cautious when using CYP3A/P-gp substrates in combination, as it may cause serious toxicity; (4) Breastfeeding patients need to stop taking medication for 7 days before resuming breastfeeding.

4 Other precautions

Women of childbearing age need to confirm that they are not pregnant and adopt efficient contraception; Elderly patients do not require special dosage adjustments; If missed, there is no need to supplement. If overdose occurs, seek medical attention immediately. When serious side effects such as jaundice, epilepsy, or loss of consciousness occur, emergency treatment should be sought.