Name: Megatope

How is this medicine (Megatope) best taken?

Use Megatope as ordered by your doctor. Read all information given to you. Follow all instructions closely.

  • It is given as a shot into a vein.
  • A drug to protect the thyroid gland will be given to you. Take it as you have been told. If this is not done, the chance of thyroid cancer later in life may be raised. Talk with your doctor.

What do I do if I miss a dose?

  • Call your doctor to find out what to do.

What are some other side effects of Megatope?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if you have any side effects that bother you or do not go away.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-FDA-1088. You may also report side effects at


Federal (USA) law prohibits dispensing without prescription

Physical characteristics

Iodine 131 decays by beta and gamma emissions with a physical half-life of 8.08 days.1

Photons that are useful for detection and imaging studies are listed in Table 1.

External Radiation

The specific gamma ray constant for iodine 131 is 2.2 R/hour-millicurie at 1 cm. The 

first half-value layer is 0.24 cm lead (Pb). A range of values for the relative attenuation

of the radiation emitted by this radionuclide that result from interposition of various

thicknesses of Pb is shown in Table 2. To facilitate control of the radiation exposure

from this radionuclide, the use of a 2.55 cm thickness of Pb will attenuate the radiation

emitted by a factor of about 1,000.



In the use of any radioactive material, care should be taken to insure minimum 

radiation exposure to the patient and occupational workers consistent with proper

patient management. 

    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 

or whether iodinate I 131 albumin affects fertility in males and females.

Pregnancy Category C

Animal reproduction studies have not been conducted with Iodinated I 131 Albumin

Injection. It is also not known whether this agent can cause fetal harm when adminis-

tered to a pregnant woman or can affect reproduction capacity. Iodinated I 131

Albumin injection should be administered to a pregnant woman only if clearly


   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

Since iodine 131 is excreted in human milk during lactation, formula feedings should 

be substituted for breast feedings.

Pediatric Use

Safety and effectiveness in children have not been established.

Adverse reactions

Although the immunological properties of albumin human are believed to be virtually 

unaltered by the iodination process, there is a theoretical possibility that allergic

reactions may occur in patients receiving additional doses a number of weeks after an 

initial dose.


iodinated i-131 albumin injection, solution
Product Information
Product Type HUMAN PRESCRIPTION DRUG LABEL Item Code (Source) NDC:50914-7731
Route of Administration INTRAVENOUS DEA Schedule     
Active Ingredient/Active Moiety
Ingredient Name Basis of Strength Strength
Inactive Ingredients
Ingredient Name Strength
# Item Code Package Description
1 NDC:50914-7731-4 8 mL in 1 VIAL, MULTI-DOSE
Marketing Information
Marketing Category Application Number or Monograph Citation Marketing Start Date Marketing End Date
NDA NDA017837 06/01/1990
Labeler - Iso-Tex Diagnostics, Inc. (181202995)
Name Address ID/FEI Operations
Iso-Tex Diagnostics, Inc. 181202995 manufacture(50914-7731)
Revised: 04/2014   Iso-Tex Diagnostics, Inc.