Mercaptopurine is a chemotherapy drug used to treat acute lymphoblastic leukemia. Understanding its side effects, mastering relief methods, and proper storage are crucial for treatment safety.

1. Common Side Effects

1.1 Myelosuppression (incidence >20%)

(1) This is the most common and dose-related adverse reaction, presenting as anemia (fatigue, pallor), leukopenia (increased risk of infection), and thrombocytopenia (bleeding tendency).

(2) Severe or recurrent myelosuppression warrants screening for TPMT or NUDT15 gene defects.

1.2 Gastrointestinal Reactions (incidence 5%-20%)

(1) Include anorexia, nausea, vomiting, diarrhea.

(2) Some patients may develop oral ulcers, which resemble thrush rather than folate antagonist-induced ulcers.

1.3 Hepatotoxicity

(1) May manifest as jaundice (yellowing of skin, sclera), elevated liver enzymes, ascites, pruritus; severe cases can lead to hepatic necrosis or hepatic encephalopathy.

(2) Jaundice typically appears 1-2 months after treatment initiation, as early as 1 week or as late as 8 years.

1.4 Other Adverse Reactions

(1) Skin reactions: rash, hyperpigmentation, photosensitivity.

(2) Others: fatigue, fever, hyperuricemia, pancreatitis, hypoglycemia (especially in children under 6 years or with low BMI), alopecia, pulmonary fibrosis.

2. Methods to Alleviate Side Effects

2.1 Management of Myelosuppression

(1) Regular monitoring: Perform routine blood tests during treatment; the doctor will adjust the dose based on absolute neutrophil count.

(2) Genetic testing: Patients with severe or recurrent myelosuppression should be tested for TPMT and NUDT15 genes. Homozygous deficient patients may require dose reduction to 10% or less of the standard dose.

(3) Infection prevention: Practice hand hygiene, avoid crowded places; seek medical attention promptly if fever or sore throat occurs.

2.2 Relief of Gastrointestinal Reactions

(1) Dietary adjustments: Eat small, frequent meals; choose bland, easily digestible foods; avoid greasy, spicy foods.

(2) Fluid replacement: Maintain hydration during diarrhea or vomiting to prevent dehydration.

(3) Prompt reporting: Inform the doctor if severe nausea, vomiting, or diarrhea affects food intake, to assess whether treatment modification is needed.

2.3 Management of Hepatotoxicity

(1) Regular monitoring: Check liver function weekly at the start of treatment, then monthly thereafter.

(2) Immediate discontinuation: If signs of hepatotoxicity (e.g., jaundice, marked elevation of liver enzymes) occur, mercaptopurine should be stopped immediately.

(3) Avoid concomitant use: Avoid using other hepatotoxic drugs simultaneously.

2.4 Skin and Daily Protection

(1) Sun protection measures: Due to possible photosensitivity, apply sunscreen, wear long sleeves and a hat when going out.

(2) Observe rash: Inform the doctor if rash or hyperpigmentation appears; most cases resolve spontaneously.

3. Storage Conditions

3.1 Temperature Requirements

Store at 20°C to 25°C (68°F to 77°F); excursions permitted between 15°C and 30°C (59°F to 86°F).

3.2 Moisture Protection

Store in a dry place. Use tight containers (as defined by USP) for dispensing to prevent moisture absorption.

3.3 Safe Handling Reminder

(1) Mercaptopurine is a cytotoxic drug. Wear gloves when handling; avoid powder contact with skin or inhalation.

(2) Expired or unused medication should be disposed of according to hazardous drug disposal regulations and not thrown away with regular trash.