Products
Pure iodine is available in specialty stores. Potassium iodide is available as a drug in tablet form and as a dietary supplement, among other products. The name iodine is obsolete and should no longer be used. Iodine stands for the chemical element and iodide for the negatively charged anion that forms salts with cations. In everyday life, the terms iodine and iodide are also used interchangeably, although this is of course chemically incorrect.
Structure and properties
Elemental iodine (I2, Mr = 253.8 g/mol) exists as brittle, grayish-purple platelets or fine crystals with a metallic luster. The substance is very sparingly soluble in water. In ethanol 96%, however, iodine is soluble. The crystals sublime slowly at room temperature, i.e. they pass directly from the solid to the gaseous state. The phase transition can be accelerated by heating. This produces violet vapors with a pungent odor. With starch, iodine shows a blue coloration. Iodine belongs to the group of nonmetals and halogens. Unlike other representatives of this group with a lower atomic number, it is not gaseous (fluorine, chlorine) or liquid (bromine) at room temperature. Negatively charged iodine is called iodide. Commonly used is the salt potassium iodide, a white powder or colorless crystals that are very soluble in water. Another salt is sodium iodide. Iodine is a rare element that used to be extracted from seaweed (-species). It accumulates in algae, fish and mollusks. The human body contains only about 10 to 20 mg.
Effects
In the human body, iodine is needed as a trace element for the formation of the thyroid hormones thyroxine and triiodothyronine and is therefore an essential dietary component. Because Switzerland is a geologically iodine-poor area, iodide is added to table salt to ensure an adequate supply for the population.
Areas of application
Povidone-iodine (Betadine, generic) is used as a disinfectant to prevent and treat infections. It is mainly used on the skin and mucous membranes. Potassium iodide is taken for struma prevention and as a food supplement. For example, potassium iodide is added to some table salts, and it is also found in multivitamin preparations and in kelp tablets. Potassium iodide is also used as a drug to prevent iodine deficiency and for the treatment of diffuse euthyroid goiter in children and adolescents. Potassium iodide tablets are used for the prevention of thyroid cancer or other thyroid diseases in case of a nuclear accident. Finally, iodine is also used in diagnostics, for example in the form of radioisotopes and as a contrast agent. Iodine is contained in various active ingredients. These include amiodarone and the thyroid hormones. Traditional preparations include:
- Lugol’s solution 2% or 5% PH, an aqueous solution of iodine.
- Ethanolic iodine solution PH (tincture of iodine).
Dosage
According to the professional information. The daily requirement for adults is 150 to 250 µg of iodide, depending on age and national recommendations. If too little iodide is supplied, hypothyroidism and iodine-deficiency goiter, formerly known as “goiter,” may develop. Another possible consequence is the so-called cretinism. For the prevention of iodine deficiency, the consumption of iodized table salt, sea fish and foods prepared with the salt is recommended. Iodine is also present in bread, milk, cheese and eggs in many countries. Special multivitamin tablets are available for pregnant and nursing women. Adequate iodine intake is important at every stage of life.
Abuse
If ammonia solution is added to elemental iodine crystals, the labile and highly explosive iodine nitrogen (NI3). Dry iodine nitrogen explodes with a loud bang at even a slight touch, which can cause hearing damage and injury.
Contraindications
Contraindications include (selection, potassium iodide):
- Hypersensitivity
- Hyperthyroidism
- Autonomous adenoma
For complete precautions, see the drug label.
Adverse effects
Iodide supplementation is usually well tolerated, provided the maximum daily doses are respected.Very rarely, hypersensitivity reactions and hyperthyroidism are reported. When used locally as an antiseptic, skin reactions may occur. Iodide must not be overdosed because this can lead to poisoning and, in the worst case, to a fatal outcome. Symptoms of acute iodine poisoning include vomiting, pain, diarrhea, dehydration, and shock. Complaints of chronic overdose include a metallic taste, inflammation of mucous membranes, skin reactions, bleeding, fever, and irritability.