Purinethol
Purinethol (mercaptopurine) is an immunosuppressive cytostatic agent and purine antagonist. It acts as an antimetabolite, interfering with nucleic acid (DNA and RNA) synthesis to inhibit the proliferation of rapidly dividing cells, particularly neoplastic leukocytes.
Dosage by Body Weight
The standard starting dose for pediatric and adult patients with acute lymphoblastic leukemia (ALL) is 1.5 to 2.5 mg/kg body weight once daily, or 50 to 75 mg/m² body surface area once daily. Dosage must be highly individualized based on clinical response, hematological tolerance, and genetic testing for TPMT (thiopurine S-methyltransferase) and NUDT15 variants.
- Body Weight
- Below 5 kg
- Dose
- 7.5 mg to 12.5 mg once daily
- Frequency
- Once daily
- Tracking Notes
- Must be calculated strictly by a pediatric oncologist, preferably using Body Surface Area (BSA). Assess genetic TPMT/NUDT15 status before starting.
- Body Weight
- 5-7 kg
- Dose
- 12.5 mg to 17.5 mg once daily
- Frequency
- Once daily
- Tracking Notes
- Calculated based on standard 2.5 mg/kg/day. Close monitoring of complete blood counts (CBC) is required.
- Body Weight
- 8-10 kg
- Dose
- 20 mg to 25 mg once daily
- Frequency
- Once daily
- Tracking Notes
- Calculated based on standard 2.5 mg/kg/day. Adjust dose if myelosuppression or hepatotoxicity occurs.
- Body Weight
- 11-15 kg
- Dose
- 27.5 mg to 37.5 mg once daily
- Frequency
- Once daily
- Tracking Notes
- Calculated based on standard 2.5 mg/kg/day. Administer on an empty stomach to ensure consistent absorption.
- Body Weight
- 16-20 kg
- Dose
- 40 mg to 50 mg once daily
- Frequency
- Once daily
- Tracking Notes
- Calculated based on standard 2.5 mg/kg/day. Regular liver function tests and CBC monitoring are mandatory.
| Body Weight | Dose | Frequency | Tracking Notes |
|---|---|---|---|
| Below 5 kg | 7.5 mg to 12.5 mg once daily | Once daily | Must be calculated strictly by a pediatric oncologist, preferably using Body Surface Area (BSA). Assess genetic TPMT/NUDT15 status before starting. |
| 5-7 kg | 12.5 mg to 17.5 mg once daily | Once daily | Calculated based on standard 2.5 mg/kg/day. Close monitoring of complete blood counts (CBC) is required. |
| 8-10 kg | 20 mg to 25 mg once daily | Once daily | Calculated based on standard 2.5 mg/kg/day. Adjust dose if myelosuppression or hepatotoxicity occurs. |
| 11-15 kg | 27.5 mg to 37.5 mg once daily | Once daily | Calculated based on standard 2.5 mg/kg/day. Administer on an empty stomach to ensure consistent absorption. |
| 16-20 kg | 40 mg to 50 mg once daily | Once daily | Calculated based on standard 2.5 mg/kg/day. Regular liver function tests and CBC monitoring are mandatory. |
Formulation
Purpose
Used primarily for the maintenance therapy of acute lymphoblastic leukemia (ALL) as part of a combination regimen. It is also used off-label for the treatment of moderate to severe inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis.
Generic Name
MercaptopurineScheduled Drug
Yes. This medicine should be supplied or used only according to applicable prescription and regulatory requirements.