Osimertinib, as a targeted drug for EGFR mutant non-small cell lung cancer, has clear contraindication requirements, including specific disease states, drug interactions, and special population restrictions, which must be strictly followed to avoid serious adverse reactions. The following categories describe their contraindications and clinical basis in detail.

1. Absolute contraindications

(1) Interstitial lung disease (ILD)/pneumonia: Patients diagnosed with ILD are permanently contraindicated as it may worsen respiratory failure or even be fatal.

(2) QT interval prolongation with arrhythmia: If baseline QTc>500ms or if there is tip twisting ventricular tachycardia, it is contraindicated and the medication needs to be permanently discontinued.

(3) Severe cardiomyopathy: It is contraindicated for symptomatic patients with congestive heart failure, as it may exacerbate the deterioration of heart function.

2 taboos for special populations

(1) Pregnancy period: Animal experiments have shown embryonic toxicity, and pregnant women using it may cause fetal malformation or death.

(2) Breastfeeding period: Medications may be secreted through breast milk, and lactating women need to discontinue medication or breastfeeding.

(3) Children: Safety and efficacy data for patients under 18 years old have not been established.

3 contraindications for drug interactions

(1) Strong CYP3A inducer: Avoid co administration with rifampicin, otherwise increase to 160mg/day and closely monitor.

(2) QT prolongation drugs: Combined use with amiodarone and other medications may cause fatal arrhythmias and should be avoided.

4 Other taboo situations

(1) Severe liver damage: There is no recommended dose for Child Pugh C patients, which may increase the risk of toxicity.

(2) End stage renal disease: Patients with creatinine clearance rate<15mL/min are contraindicated due to lack of safety data.