Purinetone Dosage/Direction for Use

Posology: 6-Mercaptopurine treatment should be supervised by a physician or other healthcare professional experienced in the management of the patients with ALL and APL (AML M3).
6-mercaptopurine may be taken with food or on an empty stomach, but patients should standardise the method of administration. The dose should not be taken with milk or dairy products. 6-mercaptopurine should be taken at least 1 hour before or 2 hours after milk or dairy products.
Special populations: Adults and paediatric population: For adults and children the usual dose is 2.5 mg/kg bodyweight per day, or 50 to 75 mg/m² body surface area per day, but the dose and duration of administration depend on the nature and dosage of other cytotoxic agents given in conjunction with 6-mercaptopurine.
The dosage should be carefully adjusted to suit the individual patient.
6-mercaptopurine has been used in various combination therapy schedules for acute leukaemia and the literature and current treatment guidelines should be consulted for details.
Studies carried out in children with acute lymphoblastic leukaemia suggested that administration of 6-mercaptopurine in the evening lowered the risk of relapse compared with morning administration.
Older population: It is advisable to monitor renal and hepatic function in these patients, and if there is impairment, consideration should be given to reducing the 6-mercaptopurine dosage.
Renal impairment: Consideration should be given to reducing the dosage in patients with impaired renal function.
Hepatic impairment: Consideration should be given to reducing the dosage in patients with impaired hepatic function.
Medicinal product interaction: When the xanthine oxidase inhibitors, such as allopurinol, oxipurinol or thiopurinol and 6-mercaptopurine are administered concomitantly it is essential that only 25% of the usual dose of 6-mercaptopurine is given since these agents decrease the rate of catabolism of 6-mercaptopurine. Concomitant administration of other xanthine oxidase inhibitors, such as febuxostat, should be avoided.
TPMT-deficient patients: Patients with inherited little or no thiopurine S-methyltransferase (TPMT) activity are at increased risk for severe 6-mercaptopurine toxicity from conventional doses of 6-mercaptopurine and generally require substantial dose reduction. The optimal starting dose for homozygous deficient patients has not been established. Most patients with heterozygous TPMT deficiency can tolerate recommended 6-mercaptopurine doses, but some may require dose reduction.
Patients with NUDT15 variant: Patients with inherited mutated NUDT15 gene are at increased risk for severe 6-mercaptopurine toxicity. These patients generally require dose reduction; particularly those being NUDT15 variant homozygotes. Genotypic testing of NUDT15 variants may be considered before initiating 6-mercaptopurine therapy. In any case, close monitoring of blood counts is necessary.
Route of administration: For oral use.