During the treatment of gefitinib, it is necessary to closely monitor four serious adverse reactions: differentiation syndrome, QT interval prolongation, pancreatitis, and liver toxicity. Early identification and timely intervention are the core strategies for reducing risks.

1、 Differentiation syndrome

1.1 Identification points: Possible symptoms include fever, difficulty breathing, low blood pressure, sudden weight gain, or peripheral edema.

1.2 Treatment measures: If any of the above symptoms occur, immediately contact a doctor for evaluation. After diagnosis, it is usually necessary to use glucocorticoid therapy and suspend medication until symptoms improve.

2、 QT interval prolongation

2.1 Monitoring requirements: Regular re examination of electrocardiogram is required before and during treatment. Patients with concomitant bradycardia, electrolyte imbalance, or taking other QT interval prolonging medications are at higher risk.

2.2 Treatment principle: If the QTc interval is significantly prolonged, the doctor may adjust the dosage, suspend administration, or permanently discontinue the medication. Avoid using drugs that may exacerbate this effect.

3、 Pancreatitis

3.1 Observation focus: Sudden severe upper abdominal pain (which can radiate to the back), nausea with vomiting.

3.2 Response strategy: If the above symptoms occur, seek medical attention immediately and test for serum amylase and lipase. After diagnosis, medication should be suspended and supportive treatment should be given.

4、 Hepatotoxicity

4.1 Monitoring items: Liver function should be rechecked weekly before and during the early stages of treatment, and monitored monthly after stabilization. Mainly observe the levels of transaminase and bilirubin.

4.2 Treatment measures: If there is a significant increase in liver enzymes, medication should be suspended. After recovery, under the guidance of a doctor, reactivate or permanently discontinue at a lower dose. At the same time, be careful to avoid co administration with other drugs that may potentially cause liver damage.