Comparative Pharmacology
Head-to-head clinical analysis: SODIUM IODIDE I 131 versus SODIUM PHOSPHATE P 32.
Peer-Reviewed Evidence
Head-to-head clinical analysis: SODIUM IODIDE I 131 versus SODIUM PHOSPHATE P 32.
SODIUM IODIDE I 131 vs SODIUM PHOSPHATE P 32
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Sodium iodide I 131 is a radioactive isotope that emits beta particles and gamma rays. It is taken up by the thyroid gland via the sodium-iodide symporter and incorporated into thyroid hormones. The beta radiation causes local destruction of thyroid tissue, reducing hormone production and treating hyperthyroidism or thyroid cancer.
Sodium phosphate P 32 is a radioactive isotope that emits beta particles, causing ionization and subsequent cell death, particularly in rapidly dividing cells. It is incorporated into DNA and RNA, concentrating in tissues with high metabolic activity such as bone marrow and neoplastic cells.
For thyroid ablation or therapy of thyrotoxicosis: 100-200 mCi (3.7-7.4 GBq) orally as a single dose. For diagnostic imaging: 5-10 μCi (0.185-0.37 MBq) orally.
Intravenous administration: 1.5 mCi (55.5 MBq) per 70 kg body weight, single dose. For polycythemia vera, oral dose: 3-5 mCi (111-185 MBq) as a single dose. Frequency is one-time or as needed based on response.
None Documented
None Documented
Physical half-life: 8.02 days. Effective half-life in euthyroid patients: ~5-7 days, but reduced to ~3-5 days in hyperthyroidism due to increased turnover. In thyroid cancer with remnant ablation, effective half-life may be longer (up to 8 days) due to reduced clearance.
Terminal elimination half-life: 14.3 days (range 13-16 days). Clinically relevant for bone marrow suppression monitoring; cumulative effect over multiple doses.
Primarily renal; approximately 90% excreted in urine within 72 hours, with the remainder eliminated via feces (biliary-fecal route, <10% in bile).
Renal: ~40% within 24 hours via glomerular filtration; Fecal: ~60% over 1-2 weeks as unabsorbed or secreted into bile. Total elimination approaches 100% after 2 weeks.
Category C
Category C
Radiopharmaceutical
Radiopharmaceutical