Potassium iodide, symbolized as KI, is a white crystalline powder commercially used in various ways. It is the most frequently used salt of iodine, added in foods, tablets, eye drops and many other therapeutic formulations.
Thus, its uses are numerous, in terms of nutrition, therapeutic intervention and industrial application. In addition to powder and tablets, it is available in liquid form as SSKI (saturated solution of potassium iodide) with one drop containing about 50 mg of iodine.
Uses of Potassium Iodide
Industrial production of potassium iodide is done by combining potassium hydroxide (KOH) with iodine (I2). You can identify old or impure potassium iodide from its yellowish coloration (pure KI is white in color). This is due to conversion of iodide into iodine after reacting with carbon dioxide.
For internal iodine uses, potassium iodide is taken orally, as syrups, plain liquid, delayed-release tablets and uncoated tablets. Major potassium iodide uses are explained here.
Iodized salt, which we usually come across in the supermarket, is nothing but table salt treated with potassium iodide. The objective is to make people get sufficient amount of iodine through their diet, and reduce the risk of iodine deficiency diseases (e.g. goiter).
Our body requires stable iodine from foods for normal functioning of the thyroid glands. Nevertheless, people living in hilly regions and those areas with poor soil receive insufficient iodine, resulting in enlarged thyroid problems and other deficiency symptoms.
To minimize such cases, potassium iodide is used in supplemental form. In tablets with 130 mg KI, the iodine content is 100 mg.
Potassium iodide is a commonly used ingredient in expectorants. It acts on the salivary glands and loosens mucus from the air passageway, thereby reducing cough. Before thyroid related surgery, KI is given to candidates for proper preparation of the gland.
The SSKI is administered in patients with severe hypothyroidism cases for managing the symptoms. Another medicinal use of this saturated solution is in treatment of a chronic fungal disease called, sporotrichosis.
Exposure to radiation causes irreversible damage to the body system, the severity of which depends on the length of exposure and concentration of the radioactive substance.
When there is release of radioactive iodine during a nuclear event, the thyroid gland absorbs it, causing severe injury to the gland. For such a condition, stable potassium iodide is delivered to block radioactive salt of iodine and protect thyroid gland from injury.
In some regions, KI is used for drinking water treatment, and its dilute form is applied for sensitization purpose. Industrial uses of potassium iodide include making dyes, soaps, lubricants and photography film emulsions.
As you have seen, potassium iodide uses are not restricted to only food or nutrition, but this stable iodine salt is used in therapeutic industry and intervention as well. On the safer side, people who have underlying diseases should not take medicine containing KI without the doctor's advice, as it may exacerbate health symptoms or interact with medicine.
Also, potassium iodide is not recommended for pregnant women and nursing mothers. For patients who are currently on iodine supplements, taking complete course of the medication as directed by the doctor is crucial to get prompt results.