Posology : מינונים

4.2   Posology and method of administration

Effective plasma levels are assumed to range between 0.01 and 0.15 g/ml. The dose must be determined exactly for each individual patient, ideally in relation to the body surface area (BSA).
Unless otherwise specified for certain combinations, cytarabine should be administered in the below indicated dosages:

Standard dosage
Induction therapy in patients with acute leukaemia
Intravenous injection 100-200 mg/m2 of body surface area, daily.
Intravenous infusion of 100 mg/m2 of body surface area, daily.
The above doses are suggested as a guideline and may be exceeded during therapy.
The duration of therapy is dependent on the clinical and morphological findings (bone marrow).
The patient may receive a treatment course of up to 7 days, which is followed by a treatment-free interval of 7-9 days to allow for sufficient recovery of the bone marrow; consolidation courses (often shorter) may subsequently be undertaken until remission or toxicity occurs.

Alternatively, therapy may be continued until bone marrow hypoplasia occurs, which is to be regarded as the tolerance limit.
Each consecutive treatment course (often shorter) must be preceded by a therapy-free interval of at least 14 days or until the bone marrow has sufficiently recovered.

Maintenance therapy in patients with leukaemia
75-100 mg/m2 of body surface area daily are administered once a month on five consecutive days, or once a week.

CNS involvement
Doses range from 5 mg/m2 to 75 mg/m2 of body surface once daily for 4 days or once every 4 days.
The most common dose is 30 mg/m2 of body surface every 4 days, until cerebrospinal fluid findings are normal, followed by one additional treatment.
The dosage schedule is usually governed by the type and severity of central nervous system manifestations and the response to previous therapy.

Lymphoma
This disease is generally treated using an appropriate combination therapy.

High-dose therapy
Unless otherwise specified, a high-dose of cytarabine is administered 3 g/m2 I.V. every 12 hours for 4-12 doses (repeated at 2-3 week intervals).
Therapies using 4-6 doses every 2 weeks or 9 doses every 3 weeks appear equally effective and less toxic.
Total dosage and duration of therapy must be determined by the treating clinician.
Depending on the number of infusions given, the treatment course may be repeated after the bone marrow has sufficiently recovered.

Combined chemotherapy
In cases of persistent leukaemia, administer additional courses (complete or modified) of any combination, as necessary, at 2-4 week intervals.
Cytarabine          100 mg/m2/day, by continuous I.V. infusion, on days 1-10 Doxorubicin         30 mg/m2/day, by I.V. infusion over 30 minutes, on days 1-3 Cytarabine           100 mg/m2/day, by I.V. infusion over 30 minutes every 12 hours, on days 1-7 Thioguanine          100 mg/m2/day, orally, every 12 hours, on days 1-7 Daunorubicin         60 mg/m2/day, by I.V. infusion, on days 5-7
Cytarabine           100 mg/m2/day, by continuous I.V. infusion, on days 1-7 Doxorubicin          30 mg/m2/day, by I.V. infusion, on days 1-3
Vincristine          1.5 mg/m2/day, by I.V. infusion, on days 1 and 5 Prednisolone         40 mg/m2/day, by I.V. infusion, every 12 hours, on days 1-5 
Cytarabine           100 mg/m2/day, by I.V. infusion, every 12 hours, on days 1-7 Daunorubicin         70 mg/m2/day, by I.V. infusion, on days 1-3
Thioguanine          100 mg/m2/day, orally, every 12 hours, on days 1-7 Prednisolone         40 mg/m2/day, orally, on days 1-7
Vincristine          1 mg/m2/day, by I.V. infusion, on days 1 and 7



Cytarabine            100 mg/m2/day, by continuous I.V. infusion, on days 1-7 Daunorubicin          45 mg/m2/day, by I.V. push, on days 1-3


Type and duration of therapy
Standard therapy
Alexan may be administered:
- intravenously as a continuous infusion,
- intravenous injection,
- intrathecal injection,
- in exceptional cases, also as a subcutaneous injection.
Due to the short half-life of cytarabine when applied intravenously, plasma levels in most patients fall below the minimum therapeutic value in less than one hour. Therefore, it is essential to split the daily dose in two or more separate doses to be given at equal intervals. Alexan solution for infusion may be prepared using physiological sodium chloride solution or 5% glucose solution. Duration of long-term infusions reportedly is in the range of 8-12 hours and 120-168 hours. Compared to single intravenous injection, administration of the same doses as a continuous infusion results in more pronounced adverse effects on the gastrointestinal tract.
In case of administration via the intrathecal route, the recommended procedure is to extract 5-8 ml of cerebrospinal fluid, mix it with the solution for injection in the same syringe and slowly re-inject the mixture.
Systemic toxicity is not expected with this method of application.
Subcutaneous injection is only applied in exceptional cases and generally only when used in maintenance therapy.
Intracutaneous injection must be avoided due to the risk of oedemas.

High-dose therapy
Alexan is administered as an intravenous infusion for 1-3 hours.
If administered by means of a perfusor, Alexan may also be given in its undiluted form.
For preparation of a diluted solution for infusion, physiological sodium chloride solution or 5% glucose solution may be used.
All Alexan preparations are compatible with each other and may be combined to prepare an individually prescribed dose. Thus no residual amounts of the medicinal product are generated.
Note: Cytarabine has been used intrathecally with hydrocortisone sodium succinate and methotrexate, both as prophylaxis in children with newly-diagnosed acute lymphocytic leukaemia, and in the treatment of meningeal leukaemia.
Prophylactic triple therapy has been reported to prevent CNS disease, and gives overall cure and survival rates similar to those seen in patients in whom CNS radiation and intrathecal methotrexate were used as initial CNS prophylaxis. The dose of Alexan was 30 mg/m2, hydrocortisone sodium succinate 15 mg/m2 and methotrexate 15 mg/m2.

Use in children
Children appear to tolerate higher doses than adults and where dose ranges are quoted, the children should receive the higher dose and the adults the lower.

Use in the elderly
There is no information to suggest that a change in dosage is warranted in the elderly.
Nevertheless, the elderly patient does not tolerate drug toxicity as well as the younger patient, and particular attention should thus be given to drug induced leucopenia, thrombocytopenia and anaemia with appropriate initiation of supportive therapy when indicated.
Use in infants
The safety of this drug for use in infants has not been established.