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Megatope Iodinated I-131 Albumin 1 mCi/mL Injection, Solution, 8 mL — NDC 50914-7731-04 package photo
Label image from the product's FDA listing (DailyMed) — may show a different pack size or an older label revision.

Megatope Iodinated I-131 Albumin 1 mCi/mL Injection, Solution, 8 mL — NDC 50914-7731-4 (Billing 50914-7731-04)

by Iso-Tex Diagnostics, Inc. · 8 mL in 1 VIAL, MULTI-DOSE

This is a package of 8 mL of Megatope Iodinated I-131 Albumin 1 mCi/mL Injection, Solution from Iso-Tex Diagnostics, Inc., marketed since May 1996 and currently FDA-listed. It is this product's only package size.

NDC 50914-7731-04
🏷️ FDA NDC (as labeled) 50914-7731-4 billing pads the package segment with a zero
Rx only Brand On market Non-controlled ⇄ Compare with another NDC
🗂️ FDA directory synced Oct 8, 2026 · this listing last changed Jul 24, 2026 · sources: openFDA · FDA label (DailyMed) · FDA Orange & Purple Book · First Databank · CMS NADAC, ASP, Medicare & Medicaid · RxNorm
📋 All sources & update times →

This page is curated, coded, and maintained by

Compiled from public FDA, CMS, DailyMed, NADAC, and related drug data sources. Editorial policy

NDC database record

One package, one record: these facts belong to NDC 50914-7731-4 alone.

Record
FDA NDC Directory package listing · Human prescription drug
Code segments
50914 labeler · 7731 product · 4 package
Package marketed since
May 21, 1996
Sample package
No — commercial package
Listing certified through
Dec 31, 2026
Barcode (UPC-A, from the NDC)
3 5091477314 0
FDA record last changed
Jul 24, 2026

Identity & classification

Regulatory identifiers FDA, NLM and CMS codes for this package

FDA NDC (as labeled) 50914-7731-4
Product NDC 50914-7731
11-digit billing NDC 50914773104
NCPDP billing unit EA — each (per item)
UNII ACH35131L1
Application # BLA017837
SPL Set ID 62ca4278-8cc9-46b7-8f3c-303ce6a9c155
Mechanism of action Radiopharmaceutical Activity
DEA schedule Non-controlled
Marketing category BLA
Marketing status On market
FDA listing status Listed (active directory)
Marketing start 1996-05-21
Route INTRAVENOUS
Dosage form INJECTION, SOLUTION
Substance HUMAN SERUM ALBUMIN I-131
Biologic (Purple Book) 351(a)

Drug-database identifiers Medi-Span GPI and First Databank GCN / HICL / AHFS classification

GCN Seq No 083109
GCN 51983
HICL code 047851
Ingredient (HICL) Albumin, Iodinated I-131
HIC1 code Z
Therapeutic class — broad (HIC1) Body As A Whole
HIC2 code Z5
Therapeutic class — intermediate (HIC2) Radiopharmaceuticals/Radiopharmaceutical Adjuvants
HIC3 code Z5D
Therapeutic class — specific (HIC3) Radioactive Diagnostics, General
AHFS code 36:00.00.00
AHFS class Diagnostic Agents
FDB label name MEGATOPE VIAL
FDB brand name Megatope
Legend status F — Federal legend — prescription drug or device
Quick answers
  • GSN (GCN sequence number): 083109
  • GCN: 51983
  • HICL (First Databank): 047851
  • AHFS class code: 36:00.00.00
Why two NDCs? The FDA registers this code as 50914-7731-4 — a 5-4-1 layout, and that's what's printed on the package and shown on DailyMed. For insurance claims, every NDC is standardized to a uniform 11-digit 5-4-2 format by adding a zero to the package segment → 50914-7731-04. Same drug, same package — only the format differs.
Where does this data come from?
Identifiers from the FDA openFDA NDC Directory and Structured Product Labeling; RxCUI from RxNorm (NLM); GPI from Medi-Span; GCN / HIC / AHFS / legend from First Databank.

Clinical

Label name MEGATOPE VIAL Ingredient Albumin, Iodinated I-131

Supplement & herbal interactions

🌿 Drug–supplement interaction checker →
Where does this data come from?
Plain-language summary from MedlinePlus (U.S. National Library of Medicine); supplement & herbal interactions and nutrient depletion data from the Natural Medicines database; our full guide is HelloPharmacist editorial content.

Pricing

A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.

Price systemPer mLPer package
Retail pharmacies payNADAC · weekly Not in the retail survey — common for institutional, discontinued, or low-volume packs.
Medicaid paysCMS SDUD · 12 mo No recent Medicaid claims on file for this NDC — rare and low-volume NDCs are suppressed in the public data.
Medicare drug plans payPart D · quarterly No Part D plan price is available for this NDC in our data.
ℹ️
No price is published for this exact package yet. CMS surveys NADAC per package size, so a different pack of the same drug often has one.
Where does this data come from?
NADAC (National Average Drug Acquisition Cost) is the CMS weekly pharmacy-acquisition-cost survey — what pharmacies pay. ASP (Average Sales Price) is the CMS Medicare Part B drug-payment file, published quarterly. Medicaid pays is computed by us from CMS State Drug Utilization Data (total reimbursed ÷ units, trailing 12 months) — gross of rebates and inclusive of dispensing fees, so it reflects what Medicaid paid, not an acquisition cost. Medicare drug plans pay is the median negotiated point-of-sale unit cost across plans listing this NDC in the CMS quarterly Prescription Drug Plan pricing files, before rebates. The VA pays is the federal contract price (FSS, and the statutory Big 4 ceiling where listed) from the VA National Acquisition Center pharmaceutical price file. All are free public government data; each measures a different payer, so the figures are not directly comparable.

Packaging — all sizes for this product

Package NDCDescription Marketing startMarketing endStatus
50914-7731-04 You're viewing this Main listing 8 mL in 1 VIAL, MULTI-DOSE 1996-05-21 — Active

Therapeutic equivalents

ProductLabelerPackNADAC/unitTEStatusPrice vs. this
Megatope 1 mCi/mLthis 50914-7731-04 Iso-Tex 8 ml — — FDA listed —
About this product: this is a biologic. Biologics don't have small-molecule generics — competition comes from FDA-licensed biosimilars (shown above), not generics.
Where does this data come from?
Equivalents are other NDCs of the same ingredient, form and route from the openFDA NDC Directory, ranked least-expensive-first by NADAC. Therapeutic-equivalence (AB) ratings come from the FDA Orange Book; biologics use the FDA Purple Book for biosimilar & interchangeable status.

Availability & biosimilar status

🏛️
1976
First FDA approval
Feb 1976
📍
2026
Currently FDA-listed
50 years listed
🧬
·
Biosimilars
see Purple Book
🧬Biologic — competition comes from biosimilars

Biologics have no small-molecule generics; biosimilar competition is tracked in the FDA Purple Book.

FDA Purple Book — biosimilars & interchangeables ⓘ
Reference product
Megatopeiodinated I-131 albumin
🔒 No FDA-licensed biosimilars or interchangeable biosimilars are listed yet for this biologic. It currently has no biosimilar competition in the FDA Purple Book.
Source: FDA Purple Book (purplebooksearch.fda.gov), matched on the reference product’s active ingredient.
Where does this data come from?
Patents and exclusivity from the FDA Purple Book (biologics), refreshed from public FDA data. Biosimilar launch timing is an estimate, not a guarantee.

Inactive Ingredients / Excipients

Inactive ingredients, also called excipients, are components of the drug product other than the active ingredient. They may include fillers, dyes, coatings, preservatives, flavors, or other formulation ingredients.

💡 Tap an ingredient (hover on desktop) to see what it is and why it’s used.

  • UNII ZIF514RVZR
    A protein derived from human blood plasma. In medicines, it acts as a stabilizer and binder, helping maintain drug potency and form, and may improve how the medication disperses or dissolves in the body.
  • UNII LKG8494WBH
    Benzyl alcohol is a clear liquid used as a preservative and solvent in medicines. It helps prevent bacterial and fungal growth and dissolves other ingredients to create uniform liquid formulations.

2 inactive ingredients listed in the exact product block matched to this NDC.

Where does this data come from?
Data sourced from official FDA Structured Product Labeling (SPL) via DailyMed — ingredient classCode="IACT" elements from the exact product block matched by this NDC. Label-section narrative from DailyMed / the openFDA label index is shown separately when available.

Inactive ingredient FAQ

Are inactive ingredients the same for every manufacturer?
No. Inactive ingredients can differ by manufacturer, dosage form, strength, and package / product version.
Why might an inactive ingredient be missing?
Some SPLs do not provide a complete structured inactive-ingredient list, and older or unusual labels may only include the information in narrative text.
Can inactive ingredients matter?
Yes. They can matter for allergies, intolerances, dyes, gluten / lactose concerns, preservatives, and formulation differences — but confirm with a pharmacist or the manufacturer when it’s clinically important.

Manufacturer & labeler

LabelerIso-Tex Diagnostics, Inc.
FDA applicationBLA017837 (BLA)
Labeler code50914
First marketedMay 1996
Product typeHuman Prescription Drug
Portfolio3 products on file

More NDCs from Iso-Tex Diagnostics, Inc. labeler code 50914

The labeler markets the product; the application holder owns the FDA approval. They’re often the same company but can differ (e.g. a repackager or an authorized generic). A mailing address / phone appears here when the manufacturer includes it in the product’s FDA label (not all do).
Where does this data come from?
Labeler, application holder and registered establishment from the FDA openFDA NDC Directory and Drugs@FDA; address/contact from the product’s FDA label.

Full prescribing information FDA SPL

The complete FDA label for this product — the official prescribing information, verbatim, section by section. Very long sections are excerpted here and marked; the full text is on DailyMed (linked in the sources below). Jump with a chip, search within the label, or expand everything.
🎯 Indications and Usage ⏱️ Dosage and Administration ⛔ Contraindications ⚠️ Warnings 🤒 Adverse Reactions 🧬 Clinical Pharmacology 📦 How Supplied / Storage and Handling 📦 Storage and Handling 📋 Description ⚠️ Precautions 📄 Package Label / Principal Display Panel
🎯 Indications and Usage 18 words ▾

INDICATIONS AND USAGE MEGATOPE is indicated in adults for use in determinations of total blood and plasma volumes.

⏱️ Dosage and Administration ~3 min read ▾

DOSAGE AND ADMINISTRATION Premedication Administer 10 drops of Strong Iodine Solution, USP (e.g., Lugol’s Solution) three times daily, beginning at least 24 hours before administration of MEGATOPE and continue for 1 week or 2 weeks thereafter to minimize the uptake of iodine-131. Recommended Dosage The recommended dose of MEGATOPE for total blood or plasma volume determination in adult patients is from 0.185 MBq to

1.85MBq (5 microCi to 50 microCi) administered intravenously. When a procedure such as a blood volume is to be repeated, do not exceed

7.4MBq (200 microCi) in any 1 week. Administration Instructions • Measure the patient dose using a suitable dose calibrator immediately prior to administration. • Use a shielded syringe for withdrawing and injecting MEGATOPE. • Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration whenever solution and container permit. MEGATOPE is a colorless to very pale yellow solution.

Do not use MEGATOPE if excessive coloration is present. • The expiration date given on the MEGATOPE vial label pertains to the stability of MEGATOPE and not to the radioactivity level. Blood Volume Determination Preparation of Reference Solution 1. Remove the amount from the vial to be used in the procedure identical in volume to the dose to be administered to the patient.

2. Prepare a reference solution using 0.9% Sodium Chloride Injection, USP as a diluent. The recommended dilution is 1:4,000 [Dilution Factor (DF) = 4,000].

3. Determine the radioactivity concentration (net cpm/mL) of the reference solution. 4.

Assay the reference solution and the blood samples (Step 3 of Administration of Dose ) using the same geometric configuration. Administration of Dose 1. Inject the dose into a large vein in patient’s arm.

Measure the residual radioactivity in the syringe and needle. 2. Do not reuse the syringe.

Dispose the syringe in accordance with the US Nuclear Regulatory Commission or Agreement State regulations pertaining to the disposal of radioactive waste. 3. At 5 minutes and 15 minutes after injecting the dose, withdraw blood samples from the patient’s other arm with a sterile heparinized syringe.

Calculation of Blood Volume 1. Take a known aliquot from each blood sample and determine radioactivity concentration in net cpm/mL. 2.

Plot the 5-minute and 15- minute sample counts (net cpm/mL) on semilog graph paper using the average count value of each sample and determine the radioactivity concentration at injection time (zero time) by drawing a straight line through the 15-minute and 5-minute points to zero time. The x ordinate of the graph is the sample withdrawal time and the logarithmic y ordinate is radioactivity concentration in net cpm/mL. 3.

Calculate patient’s blood volume (in mL) using the following formula: Net cpm/mL reference solution x DF* = blood volume (in mL) Net cpm/mL patient's blood sample *DF: Dilution factor of reference solution Sample Blood Volume Calculations Volume of blood sample aliquot = 1 mL Volume of reference solution aliquot = 1 mL Net counts at zero time = 48,100 Net counts obtained from reference solution aliquot = 52,430 Using the formula above gives 52,430 x 4,000 = 4,360 mL 48,100 Serial Blood Volume Determinations • Use a low dose of MEGATOPE to permit repetitions as often as required by clinical circumstances. • In each determination after the first dose, correct the background radioactivity remaining in the blood from former determinations by subtracting the radioactivity concentration of a blood sample obtained before the injection of MEGATOPE (i.e., background blood sample) from the radioactivity concentration of a post-injection blood sample.

Background Blood Sample 1. Prior to injecting MEGATOPE, withdraw background blood sample from large vein in patient’s arm with a sterile heparinized syringe. 2.

Leaving needle in patient’s vein, detach syringe containing blood sample. 3. Attach syringe containing the dos… [Excerpted — this section continues on DailyMed.]

⛔ Contraindications 3 words ▾

CONTRAINDICATIONS None Known.

⚠️ Warnings 32 words ▾

WARNINGS Aseptic meningitis and pyrogenic reactions have been reported following cisternography with MEGATOPE. The safety and effectiveness of MEGATOPE for cisternography have not been established. MEGATOPE is not approved for this use.

🤒 Adverse Reactions 50 words ▾

ADVERSE REACTIONS The following adverse reactions have been identified with the use of radioiodinated albumin products. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Immune System Disorders: Hypersensitivity

🧬 Clinical Pharmacology 208 words ▾

CLINICAL PHARMACOLOGY Following intravenous injection, iodinated I 131 albumin is distributed throughout the intravascular pool within 10 minutes; extravascular distribution takes place more slowly. Iodinated I 131 albumin also can be detected in the lymph and in certain body tissues within 10 minutes after injection, but maximum distribution of radioactivity throughout the extravascular space does not occur until two to four days after administration. The time at which extravascular activity is maximal has been designated as the “equilibrium time.” When this point has been reached, the radioactivity remaining in the intravascular and extravascular spaces decreases slowly and exponentially in parallel fashion.

The administered radioactivity is eliminated almost entirely in the urine, only about 2 percent of the total dose ultimately appears in the feces. The biologic half-life of iodinated I 131 albumin is dependent upon a number of factors, and published studies have varied considerably in their reporting of this figure. It has ranged, in the literature, from below 10 days to over 20 days.

One important factor affecting the biologic half-life is the initial rate of excretion, and this depends in part on the quality of the iodinated I 131 albumin. With MEGATOPE, the biologic half-life in normal individuals has been reported to be approximately 14 days.

📦 How Supplied / Storage and Handling 45 words ▾

HOW SUPPLIED MEGATOPE (iodinated I 131 albumin) injection is a colorless to very pale yellow solution available in multiple-dose vials containing the following amounts of radioactivity on the date of calibration: Complete radioassay data for each vial are provided on the MEGATOPE vial label. MegaT-5

📦 Storage and Handling 13 words ▾

Store refrigerated at 2º to 8ºC (36° to 46°F) in suitable lead shield.

📋 Description ~1 min read ▾

DESCRIPTION Chemical Characteristics MEGATOPE (iodinated I 131 albumin) injection is a sterile, nonpyrogenic, radioactive diagnostic agent for intravenous use. Each mL contains albumin human (approximately 10 mg), dibasic sodium phosphate (16 mg), guanidine hydrochloride (not more than 0.4 mg), monobasic sodium phosphate (1.6 mg), sodium chloride for isotonicity, and benzyl alcohol (9 mg) as a preservative. The stabilizers acetyltryptophanate and sodium caprylate have a concentration of less than 0.89 mM.

The pH has been adjusted to 7.2 to 7.8 with sodium hydroxide or hydrochloric acid. Each vial contains 37 MBq/mL (1,000 microCi/mL) of radioactivity as iodinated I 131 albumin at time of calibration (see HOW SUPPLIED). Physical Characteristics Iodine-131 decays by beta and gamma emissions with a physical half-life of 8.02 days.

Photons that are useful for detection and imaging studies are listed in Table 1. 1 Evaluated Nuclear Structure Data File of the Oak Ridge Nuclear Data Project DOE (1985). External Radiation The specific gamma ray constant for iodine-131 is

2.2R/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. To correct for physical decay of iodine-131, the fractions that remain at selected intervals after the time of calibration are shown in Table 3. * Calibration time MegaT-1 MegaT-2 MegaT-3

⚠️ Precautions ~2 min read ▾

PRECAUTIONS General In the use of any radioactive material, care should be taken to minimize radiation exposure to the patient and healthcare providers consistent with proper patient management. Radiopharmaceuticals should be used by or under control of healthcare providers who are qualified by specific 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 iodinated I 131 albumin affects fertility in males or females.

Pregnancy Iodine-131 crosses the placenta and can permanently impair fetal thyroid function. MEGATOPE should be administered to a pregnant woman only if clearly needed. Administration of an appropriate thyroid blocking agent is recommended before use of MEGATOPE in a pregnant woman to protect the woman and fetus from accumulation of iodine-131 (see DOSAGE AND ADMINISTRATION).

There are no data on iodinated I 131 albumin use in pregnant women to evaluate for a drug-associated risk of major birth defects, miscarriage or other adverse maternal or fetal outcomes. Animal reproduction studies have not been conducted. All radiopharmaceuticals have the potential to cause fetal harm depending on the fetal stage of development and the magnitude of the radiation dose.

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 - 4% and 15 - 20%, respectively.

Nursing Mothers Iodine-131 is present in human milk. There are no data on the effect of iodinated I 131 albumin on the breastfed infant or milk production. Because of the potential for serious adverse reactions in the breastfed infant, including transient hypothyroidism, advise women not to breastfeed during treatment with MEGATOPE and for 80 days after the final dose.

Pediatric Use Safety and effectiveness of MEGATOPE in pediatric patients have not been established. Geriatric Use Clinical studies of MEGATOPE did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients.

📄 Package Label / Principal Display Panel 2 words ▾

Packaging MegaT-newlbl

Source: FDA Structured Product Labeling, mirrored from DailyMed / openFDA. Prefer the government’s original formatting? View this label on DailyMed ↗

Reported adverse events (FAERS)

Read carefully: FAERS reports are voluntary and unverified. Counts are not incidence, do not establish causation, are subject to reporting bias, and cannot be used to compare one drug to another. Shown for signal context only. Reports for Iodinated I-131 Albumin — the ingredient across all brands.

Top reported reactions

Headache1
Lacrimation Increased1
Nausea1

Reporter sex

2 reports
Female · 100%
Reports over time (by year) — tap or hover for the count & year
2022 2023 2024 2026 1 0
Most recent year is provisional (FAERS lags ~3 months).
Where does this data come from?
Adverse-event reports from the FDA Adverse Event Reporting System (FAERS) via openFDA. FAERS reports are voluntary and unverified — counts are not incidence and don’t establish causation.

About this NDC listing & data coverage

Finished prescription product
What data is (and isn’t) available for this NDC — tap to expand
NDC identity (package / product / labeler codes) ✓ Available
Labeler ✓ Available
Product & package description ✓ Available
Marketing category & status ✓ Available
Active ingredient / dosage form / route ✓ Available
FDA label (SPL via DailyMed) ✓ Available
Package photos ✓ Available
Inactive ingredients (structured) ✓ Available
NADAC pharmacy acquisition price (CMS) — Not published for this NDC CMS publishes NADAC only for NDCs reported in its retail-pharmacy survey.
Orange Book / therapeutic-equivalence data — Not published for this NDC Applies only to products approved under an NDA/ANDA; many listings are out of scope.
HCPCS J-code billing crosswalk — Not published for this NDC Most self-administered / retail products have no J-code — that is normal.
Medicaid utilization (CMS SDUD) — Not published for this NDC CMS reports utilization only for NDCs with Medicaid claims above its privacy threshold.
“Not published” reflects what the public FDA / CMS / NLM sources provide for this exact package code — it is a property of the data feeds, not a judgment about the product.

Questions about this listing

Why is there no price listed?
The pricing shown on our NDC pages comes from CMS NADAC, a voluntary survey of retail community pharmacy invoices. CMS does not publish a NADAC for every NDC — packages outside the retail survey (institutional and hospital products, bulk packages, discontinued items, and many OTC items) may never receive one. A missing price reflects the survey's scope, not this product's actual cost, and does not mean the product is free or unavailable.
Is the NDC printed on the package the same as the 11-digit billing NDC?
Yes, they identify this exact package in different formats. The form printed on the packaging and shown on DailyMed is the one the FDA registered. Insurance claims use a fixed 11-digit 5-4-2 format, so the short segment is padded with a leading zero and the dashes are dropped. The Identity section at the top of this page lists each form of this code.
Is this package still being marketed?
Yes, per the latest FDA NDC Directory data on this page: this package is listed as actively marketed, with no marketing end date reported by Iso-Tex Diagnostics, Inc.. Listing status can change — the directory data on this page refreshes weekly.
Who lists this product with the FDA?
Iso-Tex Diagnostics, Inc. is the labeler of record for this NDC — the company under whose FDA-assigned code the package is listed. The labeler may be the manufacturer itself or a distributor marketing the product under its own code.
Do I need a prescription for this product?
This NDC is listed with FDA as a prescription product, so it is dispensed under a prescriber's order. Your pharmacist can tell you whether any over-the-counter forms of the same medication exist.
This page identifies an FDA-listed package (the NDC) and reports public regulatory and pricing data about the listing. It is reference information, not a medical recommendation — talk to your pharmacist or prescriber about your own medication.
Where does this data come from?
Listing facts (marketing category, packager status, marketing dates) from the FDA openFDA NDC Directory; label availability from DailyMed; pricing coverage from CMS NADAC; equivalence scope from the FDA Orange Book.
← 50914-7729-02 · Iso-Tex 50915-0118-60 · Shandong →
For educational and professional reference only — not medical advice. Pricing reflects published NADAC and CMS ASP (free public data) and may differ from your acquisition cost; always verify before billing or dispensing.