Idelalisib, as a PI3K δ inhibitor, has side effects mainly including hepatotoxicity, severe infections, and gastrointestinal reactions, which need to be managed through strict monitoring and preventive measures. The following is an explanation from three aspects: serious side effects that require urgent treatment, common side effects that can be self relieved, and specific preventive measures.

1. Serious side effects requiring immediate medical attention

(1) Hepatotoxicity: Lethal elevation of ALT/AST may occur, accompanied by jaundice or coagulation abnormalities. Immediate discontinuation of medication and hospitalization for treatment are required.

(2) Severe diarrhea/colitis: Do not self administer antidiarrheal medication when experiencing bloody stools, dehydration, or persistent abdominal pain. Intravenous fluid replacement and hormone intervention are necessary.

(3) Pneumonia: manifested as fever accompanied by difficulty breathing, requiring chest CT examination and initiation of anti infective treatment.

2. Common side effects that can be self relieved

(1) Peripheral edema: Mild swelling in the face or limbs usually subsides within 2-4 weeks. It is recommended to elevate the limbs and limit sodium intake.

(2) Muscle and joint pain: can be treated with hot compress or nonsteroidal anti-inflammatory drugs (under the guidance of a doctor) to avoid exacerbating symptoms with vigorous exercise.

(3) Decreased appetite: Eat small meals frequently, prioritize high protein foods, and supplement with nutritional supplements if necessary.

3. Key preventive measures

(1) Infection prevention: During treatment, avoid contact with patients with infectious diseases. If fever or cough occurs, immediate blood routine examination is required.

(2) Bleeding management: Use a soft bristled toothbrush, avoid bumps, and regularly monitor platelet counts.

(3) Contraceptive requirements: Female patients should continue to use contraception for one month after discontinuing medication, while male patients should use contraception for three months.

4. Special precautions

(1) Drug interactions: Avoid using strong CYP3A inhibitors/inducers in combination, and refrain from using grapefruit products during medication.

(2) Monitoring frequency: Check liver function every 2 weeks for the first 3 months, and then recheck every month thereafter; Monitor electrolytes daily during diarrhea.