Posology : מינונים

4.2     Posology and Method of Administration

Posology
The exact dose and duration of administration will depend on the nature and dosage of other cytotoxic drugs given in conjunction with thioguanine.

Thioguanine is variably absorbed following oral administration and plasma levels may be reduced following emesis or intake of food.

Thioguanine can be used at various stages of treatment in short term cycles. However it is not recommended for use during maintenance therapy or similar long-term continuous treatments due to the high risk of liver toxicity (see section 4.4).


Adults

The usual dosage of thioguanine is between 100 and 200 mg/m2 body surface area, per day.

Paediatric population

Similar dosages to those used in adults, with appropriate correction for body surface area, have been used.

Use in the elderly

There are no specific dosage recommendations in elderly patients (See dosage in renal or hepatic impairment).

Thioguanine has been used in various combination chemotherapy schedules in elderly patients with acute leukaemia at equivalent doses to those used in younger patients.


Dosage in renal or hepatic impairment
Consideration should be given to reducing the dosage in patients with impaired hepatic or renal function.


TPMT-deficient patients
Patients with inherited little or no thiopurine S-methyltransferase (TPMT) activity are at increased risk for severe tioguanine toxicity from conventional doses of tioguanine and generally require substantial dose reduction. The optimal starting dose for homozygous deficient patients has not been established (see sections 4.4 and 5.2).

Most patients with heterozygous TPMT deficiency can tolerate recommended tioguanine doses, but some may require dose reduction. Genotypic and phenotypic tests of TPMT are available (see sections 4.4 and 5.2).


Method of administration
Oral.