Indications
Therapy of polycythemia vera and polythrombocytemia and related disorders, leukemia and other neoplastic haematological disorders and in diagnosis for certain ocular tumors. Palliative treatment of painful bone metastasis from prostate, breast, lung and other carcinomas is reported but its myelotoxicity should be considered.
Dosage
The preparation is destined for direct oral or intravenous administration to the patient in aliquots varying in activity depending on therapeutic application. Recommended dose is 74 - 111 MBq (2 - 3 mCi) on 1 m2 of body surface but not more than 185 MBq (5 mCi) In leukemia approximately 37 - 74 MBq (1 to 2 mCi) is given weekly until the white blood cell count is sufficiently decreased.
Contraindications
If the patients platelet count is less than 15000 it is suggested not to administer the preparation.
Interactions
Interactions with other drugs are not known; with respect to the adverse effect on bone marrow, the product should not be administered simultaneously with chemotherapy and radiation therapy (or within a short interval after them), if the therapeutic effect does not outbalance the risk.
Pregnancy and lactation
When it is necessary to administer radioactive medicinal products to women of childbearing potential, information should always be sought about pregnancy. Breast feeding should be discontinued after administration because of the potential hazard to the suckling.
Undesirable effects
Therapy with P-32 Sodium orto-phosphate injection gives the risk of leukemia in 2 - 15 % of patients during 10 years (similar to chemotherapy).
Overdose
The preparation is delivered in portions prepared on request with the patient activity dose calculation performed by responsible physician. Should an accidental administration of an excess of radioactive substance occur, the radiation risk can be reduced by induction of a frequent voiding.
Composition
40 - 400 MBq of P-32 phosphoric acid
1 mg/ml of P in sodium orto-phosphate, Na2HPO4 x 12 H2O
0,9 mg/ml of Sodium chloride
The product does not contain any antimicrobial additives.
Product specification
Radiochemical purity > 99.0 %
Radionuclide purity > 99.5 %
pH 6.0 - 7.0
Pharmacological properties
After injection the soluble radiophosphate is concentrated by rapidly proliferating tissue. The blood cells precursors in the bone marrow divide and proliferate rapidly in health and even more so in these diseases. The radionuclide P-32 present in sodium orthophosphate-P-32 selectively concentrates in the mitotically active cells of the bone marrow and in trabecular and cortical bone.
Radiation dosimetry
Phosphorus - P-32 is a beta emitter (Emax = 1,71 MeV) with a physical half-life of 14,29 days. It gives off Bremsstrahlung. According to ICRP model, a fraction of 0.30 of intravenously administered activity is assumed to go to mineral bone and to be permanently retained, and 0.70 is assumed to be distributed in soft tissues. Phosphorus metabolism is complex. Activity deposited in soft tissues is assumed to be rapidly eliminated from the body (30%) and about 40% of activity possesses a 19-day biological half-life, the remaining 30% is reduced by radioactive decay. The high-energy beta emissions can present a substantial skin dose hazard.
The effective dose equivalent at adult patient (70kg) after administration of P-32 Sodium orthophosphate is 2.20 mSv/MBq. The radiation dose absorbed in breast is about 0.92 mGy/MBq, in the bone marrow 11.0 mGy/MBq and in bone surfaces about 11.0 mGy/MBq. In other organs, the absorbed radiation doses are lower (0.74 mGy/MBq).
Lifetime
14 days from the reference day.
Storage
Store at room temperature, 5 - 25 C, in accordance with regulations pertaining to health safety from ionizing radiation.
Special precautions
The radiopharmaceutical can be used by authorized personnel only.
It must be handled with care and appropriate safety measures should be used to minimalize radiation exposure of the clinical staff and the patient. The approvals for their acquisition and administration are subject to relevant national regulations.