Comparative Pharmacology
Head-to-head clinical analysis: SODIUM IODIDE I 123 versus SODIUM IODIDE I 131.
Peer-Reviewed Evidence
Head-to-head clinical analysis: SODIUM IODIDE I 123 versus SODIUM IODIDE I 131.
SODIUM IODIDE I 123 vs SODIUM IODIDE I 131
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Sodium iodide I 123 is a radioactive isotope that emits gamma radiation. Following oral or intravenous administration, it is rapidly absorbed and selectively concentrated in the thyroid gland via the sodium-iodide symporter (NIS). The emitted gamma rays allow for imaging of thyroid tissue and detection of abnormal uptake patterns.
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.
Oral: 400-800 μCi (14.8-29.6 MBq) for thyroid uptake studies; 150-300 μCi (5.6-11.1 MBq) for thyroid scan. Administer orally as a single dose.
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.
None Documented
None Documented
13.2 hours (physical T1/2); effective T1/2 ~13 hours in euthyroid; prolonged in hypothyroidism.
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.
Primarily renal (90%) as iodide; small amount feces (<5%) and negligible biliary.
Primarily renal; approximately 90% excreted in urine within 72 hours, with the remainder eliminated via feces (biliary-fecal route, <10% in bile).
Category C
Category C
Radiopharmaceutical
Radiopharmaceutical