Sodium iothalamate I-125 injection

What Sodium iothalamate I-125 injection is used for

Quoted from the “Indications and Usage” section of the FDA-approved label.

GLOFIL-125 (Sodium Iothalamate I-125 Injection) is indicated for evaluation of glomerular filtration in the diagnosis or monitoring of patients with renal disease.

— FDA label: Glofil-125, Iso-Tex Diagnostics, Inc., effective December 9, 2019. Read the full label on DailyMed →

Label quoted: the one for the most common form (injection, solution, intravenous), Glofil-125, Iso-Tex Diagnostics, Inc.; it covers 1 product in the FDA NDC Directory. The side effects, interactions, dosage and pregnancy quotes below come from this same label.

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Boxed warning

A boxed warning (“black box”) is the FDA’s strongest warning on a drug label, for serious or life-threatening risks.

The label quoted above has no boxed warning.

Sodium iothalamate I-125 injection dosage

Quoted from the “Dosage and Administration” section of the FDA-approved label. Your own dose is the one your doctor prescribes: do not change it on your own.

Dosage The suggested dose range employed in the average patient (70 kg) is as follows: Continuous intravenous infusion: 20 to 100 μCi (0.74-3.7 megabecquerels) (Sigman, et al (1) method). Single intravenous injection: 10 to 30 µCi (0.37-1.11 megabecquerels) Cohen, et al (2) method) The patient dose should be measured by a suitable radioactivity calibration system immediately prior to administration.

Read more of this section

Technique Continuous intravenous infusion Sigman 1 method I. Preparation: Adequate diuresis (a urine flow exceeding 3 mL/min.) is established, preferably by an oral water load of 1,500 mL two hours prior to the beginning of the clearance study. 2. It is not necessary to withhold breakfast or admit the patient the night before. II. Procedure: After the establishment of adequate diuresis, a number 14 or 16 French Foley catheter is aseptically inserted into the bladder. An intravenous infusion of Lactated Ringers (Hartmanns) solution is started in each arm, one to maintain a site for injection of the GLOFIL-125, the other to serve as a site for serial withdrawal of blood. A two-way stopcock connects the needle and intravenous tubing of each arm. The dose is equally divided into (1) an intravenous priming dose to be injected as is and (2) a sustaining dose to be diluted in 30 to 60 mL of isotonic sodium chloride, depending on how many collection periods are anticipated. The priming dose is slowly injected into one arm. This is immediately followed by infusion of the sustaining solution through the same site, usually at the rate of 0.5 mL/min., by means of an automatic pump. During this infusion, the Lactated Ringers solution in the same arm is discontinued, and 40 to 45 minutes are allowed for equilibration in order to reach a state of constant plasma concentration of radioactivity. After attaining equilibrium, consecutive 15 minute collection periods are started. From the arm opposite the injection site, 5 mL of blood (allowing duplicate plasma counting volumes) is drawn six minutes prior to the midpoint of each collection period, placed in heparinized tubes, mixed, and centrifuged. The blood samples may be obtained through the two-way stopcock after discarding the first 30 mL aspirated into the syringe. This 30 mL contains the contents of the tubing, including infusion fluid, and must be cleared in order to obtain an undiluted blood sample. If desired, this step may be eliminated and blood samples obtained by direct venipuncture. During each collection period, total urine must be accurately collected and the volume accurately measured. Three such consecutive collection periods are sufficient for most clinical studies. III. Clearance Calculations: 1. Aliquots (1 mL each) of plasma and urine from each collection period are counted in a standard gamma-ray scintillation well detector. 2. All counts are corrected for background activity. 3. Glomerular filtration rate is calculated by the formula C=UV/P, in which: C = glomerular filtration rate in mL/min U= urinary concentration of radioactivity in net counts/min/mL V= urinary flow rate in mL/min P = plasma concentration of radioactivity in net counts/min/mL 4.

— FDA label: Glofil-125, Iso-Tex Diagnostics, Inc., effective December 9, 2019. This is part of the section. Read the full label on DailyMed →

When Sodium iothalamate I-125 injection should not be used

Quoted from the “Contraindications” section of the FDA-approved label.

GLOFIL-125 should not be administered via a central venous line.

— FDA label: Glofil-125, Iso-Tex Diagnostics, Inc., effective December 9, 2019. Read the full label on DailyMed →

Forms and how it is given

Companies that list this medicine

Labelers in the FDA NDC Directory: the company named on the package (maker or distributor), with the number of prescription products.

• Iso-Tex Diagnostics, Inc.1 product

FDA approval history

• NDA: New Drug Application: how a new (usually brand-name) medicine is approved.

Shortage status

The FDA drug shortage list does not show these products.

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Recalls

No recall linked to these products (by their NDC code) appears in the FDA enforcement reports.

Official identifiers

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Sources

1. FDA-approved label on DailyMed (National Library of Medicine) — Glofil-125, Iso-Tex Diagnostics, Inc., effective December 9, 2019; via openFDA, FDA data exported October 30, 2026, retrieved October 31, 2026
2. NDC Directory (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 30, 2026, retrieved October 31, 2026
3. Drugs@FDA (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 30, 2026, retrieved October 31, 2026
4. Drug recall enforcement reports (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 27, 2026, retrieved October 31, 2026
5. Drug shortages (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 30, 2026, retrieved October 31, 2026

openFDA data is provided by the FDA as is; it may be incomplete. Always rely on the label that comes with your medicine. FDA Enforcement Report search →

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