Over-the-counter medicine
Potassium iodide Brand names: Iosat; first approved as Thyro-Block
Potassium iodide (Iosat) is an over-the-counter medicine with an FDA approval on record since 1979. FDA's NDC Directory lists it from 3 generic labelers.
- Generic listed
- Over the counter
Check it at the source: the potassium iodide FDA label on DailyMed (effective October 3, 2025, Anbex Inc.); the NDA 18307 record on Drugs@FDA; every potassium iodide label on DailyMed.
Highlights of the record
FDA label of October 3, 2025; NDC Directory, Drugs@FDA and Orange Book, October 8, 2026
Used for
From the label: indications and usageHelps prevent radioactive iodine from getting into the thyroid gland during a nuclear radiation emergency.
Forms and strengths
- 65 mg
- 130 mg
- 65 mg/ml
Tablet; solution.
On the market
- Earliest approval on file
- November 9, 1979 Thyro-Block, Meda Pharms; Drugs@FDA’s file, where older or withdrawn approvals can be missing
- Generic approvals
- 3 first September 10, 2002; 2 with a marketed status in Drugs@FDA
- Labelers listed (NDC)
- 4 of which 3 under generic applications, 1 under brand applications, repackagers included
Supply and safety
- Pharmacy cost (NADAC)
- Not in the survey
- Shortage (FDA)
- No current entry
- Recalls by its makers (FDA)
- No recall recorded
- FAERS reports
- 1,474 through July 30, 2026
What is potassium iodide used for?
From the label: indications and usageHelps prevent radioactive iodine from getting into the thyroid gland during a nuclear radiation emergency. Use along with other emergency measures recommended by public officials. INDICATIONS IOSAT™ (Potassium Iodide tablets, USP) is a thyroid blocking medicine that is used in a nuclear radiation emergency only.
Source: FDA drug label (IOSAT), Anbex Inc., effective October 3, 2025 (SPL set bab815ee-47ef-4c87-a60d-e0d7863ad871), via openFDA; the full label on DailyMed
Is there a generic for potassium iodide (Iosat)?
The FDA approved the first generic potassium iodide on September 10, 2002. 3 generic applications are approved; 2 of them carry a current (not discontinued) marketing status in Drugs@FDA; that status is not evidence that the generic is on sale.
FDA's NDC Directory lists potassium iodide from 3 labelers under a generic (ANDA) application and from 1 brand labeler. A listing means the company has registered the product for sale; it does not show that every pharmacy stocks it.
- 1979 earliest approval on file
- 2002 first generic approved
Source: Drugs@FDA, FDA NDC Directory and the Orange Book (openFDA bulk files, October 8, 2026)
What does the potassium iodide label say about other medicines?
The potassium iodide label names 1 other medicine in its interaction, contraindication or warning sections. The labels of 1 other medicine name potassium iodide. The sentences are the labels' own; a label lists what its studies and reports found, not every interaction.
| Medicine named | Section | What the label says |
|---|---|---|
| Lithium | drug interactions (prescription label) | Drug Interactions: Concurrent use with lithium or antithyroid drugs may potentiate the hypothyroid and goitrogenic effects of these medications. |
Source: FDA drug label (IOSAT), Anbex Inc., effective October 3, 2025 (SPL set bab815ee-47ef-4c87-a60d-e0d7863ad871), via openFDA; the full label on DailyMed
What do FAERS reports show for potassium iodide?
The FDA Adverse Event Reporting System holds 1,474 reports that list potassium iodide among the medicines taken, through July 30, 2026, each a report of something that happened, not proof the medicine caused it; 389 are coded as a death and 521 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is.
Reports received each year
The most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026
What next?
- Potassium iodide side effects
- the label's list beside FAERS reports
- Check an interaction
- what two or more labels say about each other