The contraindications of Crizotinib mainly involve specific drug interactions, severe underlying diseases, and special physiological states, which need to be strictly avoided to reduce the risk of fatal adverse reactions. It is also important to pay attention to standard usage and dosage.

1. Taboos of drug interactions

(1) Prohibition of combination with potent CYP3A inducers (such as phenytoin, carbamazepine, rifampicin) may lead to a significant decrease in blood concentration of crizotinib and render it ineffective.

(2) Avoiding combination with potent CYP3A inhibitors (such as ketoconazole and clarithromycin) may increase the risk of QT interval prolongation and apical torsion ventricular tachycardia.

2. Contraindications for cardiovascular system

(1) Patients with congenital long QT syndrome or baseline QTc>500ms are contraindicated as crizotinib may exacerbate arrhythmia.

(2) Uncontrolled severe heart failure (NYHAIII-IV grade) is contraindicated, as the medication may further impair cardiac function.

3. Liver function contraindications

(1) It is contraindicated for patients with Child Pugh C grade liver dysfunction, as significant inhibition of crizotinib metabolism may lead to toxic accumulation.

(2) When active viral hepatitis is accompanied by ALT/AST>5 times ULN, it is contraindicated and medication should be evaluated after controlling the liver disease.

4. Taboos for special physiological states

(1) Prohibited during pregnancy, animal experiments have shown the risk of embryonic lethality and malformation, and women of childbearing age need to use contraception during the medication period.

(2) Prohibited during lactation, the medication can be secreted through breast milk and its safety for infants has not been established.

5. Other absolute taboos

(1) It is contraindicated for individuals allergic to crizotinib or excipients, as it may cause severe hypersensitivity reactions.

(2) Patients with severe renal insufficiency (eGFR<30mL/min) who have not undergone dialysis are prohibited from using it and need to adjust the dosage regimen.

6 Standard Dose Protocol

(1) Adult non-small cell lung cancer: 250mg per dose, taken orally twice a day, on an empty stomach or with food.

(2) ALK positive anaplastic large cell lymphoma in children: 280 milligrams per square meter twice a day for those with a body surface area ≥ 1.2 square meters; For those with an area of less than 1.2 square meters, take 250 milligrams per square meter twice a day.