Rx Drugs Info

sodium phosphate p 32 (Sodium Phosphate, P-32solution 
[Mallinckrodt Inc.]

Rx Only.


Sterile, non-pyrogenic Sodium Phosphate P 32 is available for therapeutic application as an intravenous solution dosage form with a concentration of 24.8 megabecquerels (0.67 millicurie) per milliliter. The intravenous solution contains 1.6 milligrams per milliliter of sodium acetate as a buffer, 0.9% sodium chloride for isotonicity and may contain sodium hydroxide or hydrochloric acid for pH adjustment. The pH of the solution is between 5.0 and 6.0.


Phosphorus P 32 decays by beta emission with a physical half-life of 14.3 days.1 The mean energy of the phosphorus P 32 beta particle is 694.9 keV.

Table 1. Principal Radiation Emission Data
Radiation Mean Percent Per Disintegration Mean Energy (keV)
Beta-1 100.0 694.9

Kocher, David C., “Radioactive Decay Data Tables,” DOE/TIC 11026, page 70 (1981).


The range of the phosphorus P 32 beta particle, which has a maximum energy of 1.71 MeV, is 2.8 mm of aluminum.

To correct for physical decay of this radionuclide, the fractions remaining at selected time intervals before and after the day of calibration are shown in Table 2.

Table 2. Physical Decay Chart; Phosphorus P 32, Half-Life 14.3 days

*Calibration Day

Days Fraction Remaining Days Fraction Remaining
0* 1.000 30 0.233
1 0.953 35 0.183
2 0.908 40 0.144
5 0.785 45 0.113
10 0.616 50 0.089
15 0.483 55 0.070
20 0.379 60 0.055
25 0.297


Phosphorus is necessary to metabolic and proliferative activity of cells. Radioactive phosphorus concentrates to a very high degree in rapidly proliferating tissue.


The principal use of Sodium Phosphate P 32 is for the treatment of polycythemia vera, and it is effective for the treatment of chronic myelocytic leukemia and chronic lymphocytic leukemia. Sodium Phosphate P 32 is also used in palliative treatment of selected patients with multiple areas of skeletal metastases.


Sodium Phosphate P 32 should not be used as a part of sequential treatment with a chemotherapeutic agent.

In polycythemia vera, Sodium Phosphate P 32 should not be administered when the leukocyte count is below 5,000/cu mm, or a platelet count is below 150,000/cu mm.

In chronic myelocytic leukemia, Sodium Phosphate P 32 should not be administered when the leukocyte count is below 20,000/cu mm.

For treatment of bone metastases it is usually not administered when the leukocyte count is below 5,000/cu mm, and platelet count is below 100,000/cu mm.


This radiopharmaceutical should administered for intracavitary use.

Overdose of Sodium Phosphate P 32 may produce serious effects on the hemopoietic system. The blood and bone marrow should be carefully monitored at regular intervals.

Sodium Phosphate P 32 ordinarily does not localize in retinoblastomas.



As in the use of any other radioactive material, care should be taken to insure minimum radiation exposure to the patient, consistent with proper patient management, and to insure minimum radiation exposure to occupational workers.

Radiopharmaceuticals should be used only by physicians who are qualified by training and experience in the safe use and handling of radionuclides and whose experience and training have been approved by the appropriate government agency authorized to license the use of radionuclides.

Carcinogenesis, Mutagenesis, Impairment of Fertility

No long-term animal studies have been performed to evaluate carcinogenic potential, mutagenic potential, or whether Sodium Phosphate P 32 affects fertility in males or females.

Pregnancy Category C

Animal reproduction studies have not been conducted with Sodium Phosphate P 32. It is also not known whether Sodium Phosphate P 32 can cause fetal harm when administered to a pregnant woman or can affect reproductive capacity. Sodium Phosphate P 32 should be given to a pregnant woman only if clearly needed.

Ideally, examinations using radiopharmaceuticals, especially those elective in nature, of a woman of childbearing capability should be performed during the first few (approximately 10) days following the onset of menses.

Nursing Mothers

It is not known whether this drug is excreted in human milk. As a general rule, nursing should not be undertaken when a patient is being given Sodium Phosphate P 32.

Pediatric Use

Safety and effectiveness in pediatric patients have not been established.


None known.


The patient dose should be measured by a suitable radioactivity calibration system immediately prior to administration.

Oral administration of high-specific-activity Sodium Phosphate P 32 in the fasting state may equal intravenous administration.

Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.

Waterproof gloves should be used during the entire handling and administration procedure.

Maintain adequate shielding during the life of the product and use a sterile, shielded syringe for withdrawing and injecting the drug.

For polycythemia vera, intravenous dosages from 37 to 296 megabecquerels (1 to 8 millicuries) are given depending upon the stage of disease and size of the patient. Repeat doses must be adjusted to individual needs.

For chronic leukemia, the individual dose is 222 to 555 megabecquerels (6 to 15 millicuries), usually administered with concomitant hormone manipulation.


The estimated absorbed radiation doses2 to an average patient (70 kg) following intravenous administration of 555 megabequerels (15 millicuries) of Sodium Phosphate P 32 are shown in Table 3.

Table 3. Absorbed Radiation Doses
Absorbed radiation doses for 555 megabecquerels (15 millicuries)
Tissue grays rads
Skeleton 9.45 945
Liver 0.93 93
Spleen 1.10 110
Brain 0.45 45
Testes 0.15 15
Ovaries 0.12 12
Total Body 1.50 150

Method of Calculation: “S”, Absorbed Dose per Unit Cumulated Activity for Selected Radionuclides and Organs, MIRD Pamphlet #11 (1975).


Catalog Number 461

Sodium Phosphate P 32 is supplied as a sterile, non-pyrogenic solution in single dose vials containing 185 megabequerels (5 millicuries) of phosphorus P 32. Each milliliter contains 24.8 megabecquerels (0.67 millicuries) sodium phosphate P 32 at the time of calibration, 1.6 milligrams sodium acetate and 9 milligrams sodium chloride. The solution may contain sodium hydroxide or hydrochloric acid for pH adjustment.


Store at controlled room temperature 20-25°C (68-77°F).

Storage and disposal of Sodium Phosphate P 32 Solution should be controlled in a manner that is in compliance with the appropriate regulations of the government agency authorized to license the use of this radionuclide.

The U.S. Nuclear Regulatory Commission has approved distribution of this radiopharmaceutical to persons licensed to use byproduct material listed in Section 35.300, and to persons who hold an equivalent license issued by an Agreement State.

Revised 11/2000
Mallinckrodt Inc.
St. Louis, MO 63134


Sodium Phosphate P 32 (Sodium Phosphate, P-32)
Product Code 0019-N461 Dosage Form SOLUTION
Route Of Administration INTRAVENOUS DEA Schedule
Name (Active Moiety) Type Strength
Sodium Phosphate, P-32 (Sodium Phosphate, P-32) Active 0.67 MILLICURIE  In 1 MILLILITER
sodium acetate Inactive 1.6 MILLIGRAM  In 1 MILLILITER
sodium chloride Inactive 0.9 MILLIGRAM  In 1 MILLILITER
sodium hydroxide Inactive  
hydrochloric acid Inactive  
Characteristic Appearance Characteristic Appearance
Color Score
Shape Symbol
Imprint Code Coating
# NDC Package Description Multilevel Packaging
1 0019-N461-F0 1 VIAL In 1 CAN contains a VIAL
1 7.5 MILLILITER In 1 VIAL This package is contained within the CAN (0019-N461-F0)

Revised: 03/2007Mallinckrodt Inc.

Data are from FDA and U.S. National Library of Medicine.