Idelalisib (Zydelig) is an oral PI3Kδ inhibitor indicated for the treatment of relapsed chronic lymphocytic leukemia (CLL).

I. Dosage and Administration

1. Standard Dosage

(1) The recommended dose is 150 mg orally, twice daily.

(2) Administer doses approximately 12 hours apart, with or without food.

(3) Swallow tablets whole; do not chew, crush, or split.

2. Missed Dose Management

(1) If a dose is missed by less than 6 hours, take the missed dose immediately, and resume the subsequent dose per original schedule.

(2) If more than 6 hours have elapsed since the missed dose, skip the missed dose entirely, and take the next dose at the regular scheduled time.

(3) Do not take a double dose to compensate for a missed dose.

3. Dosage Adjustment

(1) For adverse reactions, the dose may be reduced to 100 mg twice daily.

(2) Discontinue treatment for severe or life-threatening toxicities. Upon recovery, restart therapy at 100 mg twice daily.

(3) Permanently discontinue treatment if toxicity recurs following dose reduction.

II. Warnings and Precautions

1. Monitoring Before and During Treatment

(1) Complete liver function tests and complete blood count (CBC) prior to treatment initiation.

(2) Monitor alanine transaminase (ALT) and aspartate transaminase (AST) every 2 weeks for the first 3 months of treatment, every 4 weeks for the subsequent 3 months, and every 1 to 3 months thereafter.

(3) Monitor complete blood count at least every 2 weeks for the first 6 months of therapy.

(4) All patients require prophylaxis against Pneumocystis jirovecii pneumonia (PCP).

2. Urgent Medical Attention Warning Symptoms

(1) Jaundice (yellowing of skin or sclera), dark urine, right upper abdominal pain, abnormal bleeding or bruising.

(2) An increase of ≥6 bowel movements per day from baseline.

(3) New or worsening cough, dyspnea, or hypoxia.

(4) Fever or any signs of infection.

(5) Severe abdominal pain accompanied by chills, nausea, and vomiting.

(6) Severe skin rash, blistering, or oral mucosal ulceration.

3. Contraception Requirements

(1) Females of reproductive potential must undergo pregnancy testing prior to treatment initiation. Effective contraception must be used throughout treatment and for 1 month after the final dose.

(2) Males engaging in sexual activity with female partners of reproductive potential must use effective contraception throughout treatment and for 3 months after the final dose.

III. Healthy Lifestyle Recommendations for Patients

1. Dietary Management

(1) High-fat meals increase drug absorption by 1.4-fold. Maintain a consistent administration pattern (with or without food) to avoid substantial fluctuations in plasma drug concentration.

(2) During diarrheal episodes, avoid greasy and spicy foods. Adopt small, frequent meals and adequate fluid intake to prevent dehydration.

2. Infection Prevention

(1) Given a 48% incidence of infection, patients should practice frequent hand hygiene, avoid crowded public areas, and wear face masks.

(2) Seek immediate medical care upon fever onset. Receive scheduled vaccinations; live vaccines are contraindicated.

3. Daily Self-Monitoring

(1) Record daily bowel movement frequency; monitor body weight and body temperature.

(2) Closely monitor for new-onset skin rashes.

(3) Attend regular follow-up appointments for complete blood count and liver function testing. Fatigue is a common adverse effect; ensure sufficient rest and moderate physical activity.

4. Drug Storage

(1) Store Idelalisib in the original container at 20°C to 30°C, and keep out of reach of children.

(2) Do not use if the container seal is damaged or missing.