Povidone-Iodine

Products

Povidone–iodine is commercially available as ointment, solution, gargle, ointment gauze, vaginal suppositories, and soap (Betadine, generic), among other products. It was developed in the 1950s and has been approved in many countries since 1969.

Structure and properties

Povidone–iodine is a complex of povidone and iodine. It has a content of 9.0 to 12.0% available iodine, based on the dried substance. Povidone-iodine exists as a yellowish brown to reddish brown amorphous powder that is soluble in water. The average molecular mass of povidone is approximately 40 kDa.

Effects

Povidone-iodine (ATC D08AG02) has antimicrobial properties against bacteria, fungi, viruses, some protozoa and, with prolonged exposure, additionally against spores. The effects are due to the oxidizing and halogenating (iodinating) effects of elemental iodine. Decolorization of the drugs indicates a loss of effect. Povidone-iodine additionally has anti-inflammatory properties. Resistance is not observed. Unlike tincture of iodine, the iodine is released more slowly, the effects last longer, and povidone-iodine causes fewer side effects. Thus, the povidone prolongs the duration of action and increases tolerability.

Indications

As a disinfectant for the prevention and treatment of infections. Povidone-iodine is used especially on the skin and mucous membranes.

Dosage

According to the technical and patient information. Application depends on the product. Some drugs can be used directly, others must be diluted beforehand.

Contraindications

  • Hypersensitivity
  • Hyperthyroidism or other manifest thyroid disease
  • Dermatitis herpetiformis Duhring
  • Before and after radio-iodine application
  • Newborns and infants under 6 months of age.
  • Use of the gargle concentrate in children under 6 years (risk of swallowing).
  • Pregnancy and lactation

Full precautions can be found in the drug label.

Interactions

Organic material such as proteins and pus may cause attenuation of effect. The same is true for other disinfectants such as silver sulfadiazine, hydrogen peroxide, taurolidine, and octenidine. Large-scale and prolonged use in patients on lithium therapy may induce hypothyroidism. Povidone-iodine should not be combined with mercury because the corrosive mercury iodide may form. However, disinfectants containing mercury are rarely used today.

Adverse effects

Possible adverse effects include allergic reactions and contact dermatitis. With prolonged treatment, wound healing disorders and local discomfort such as pain, a burning sensation, and a feeling of warmth may occur. If used for too long and in high doses, other side effects are possible:

The drugs are brown because of the iodine they contain and can leave stains on textiles. These can usually be removed with soap and water because povidone-iodine is water soluble. In the technical information, sal ammoniac is also recommended. In our view, this is not advisable because it could theoretically produce the explosive iodine nitrogen.