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Medical uses of silver

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Colloidal silver is a liquid suspension of microscopic particles of silver. A colloid is technically defined as particles which remain suspended without forming an ionic, or dissolved solution. The broader commercial definition of "colloidal silver" includes products that contain various concentrations of ionic silver, silver colloids, ionic silver compounds or bound proteins in purified water. Colloidal silver with concentrations of 30 parts per million (ppm) or less are typically manufactured using an electrolysis process, whereas colloidal silver with higher concentrations of 50 ppm or more are usually silver compounds that have been bound with a protein.

Colloidal silver is currently marketed for internal and external use as an alternative medical remedy though there is no scientific evidence of its effectiveness in vivo. Some in vitro studies demonstrate an anti-bacterial effect of electrically generated silver ions, although a study of a colloidal silver solution marketed on the Internet showed no such antimicrobial activity. Excessive ingestion of colloidal silver can result in argyria, a cosmetic condition in which the skin irreversibly turns blue or grey.

Historical applications

Silver has had some medicinal uses going back for centuries. In the early 1900s, silver gained regulatory approval as an antimicrobial agent. However, the use of silver diminished with the introduction of antibiotics in the early 1940s. A few prescription drugs containing silver are still available. Prior to 1938, colloidal silver was used as a germicide and disinfectant. Physicians used it as an eyedrop for ophthalmic problems, for various infections, and sometimes internally for diseases such as tropical sprue, epilepsy, gonorrhea, and the common cold.

Current applications

From approximately 1990, especially with the emerging problem of antibiotic resistance , there has been a resurgence of the promotion of colloidal silver as an alternative medicine treatment, marketed with claims that it can prevent or treat numerous diseases. In vitro evidence of an antimicrobial effect of colloidal silver is mixed; one study has found it to lack any antibacterial effect, while others have reported colloidal solutions of 5-30ppm as being effective against staphylococci and E.coli There have been no clinical trials showing that any preparation of colloidal silver is effective in vivo.

Colloidal silver products are legally available at health food stores in the United States and Australia and are marketed over the Internet as a dietary supplement. It is illegal in the U.S. and Australia for marketers to make claims of medical effectiveness for colloidal silver, but some websites still list its use for the prevention of colds and flu, and the treatment of more serious conditions such as diabetes, cancer, chronic fatigue syndrome, HIV/AIDS, and tuberculosis, among other diseases. There is no medical evidence that colloidal silver is effective for any of these claimed indications. Silver is not an essential mineral in humans; there is no dietary requirement for silver, and no such thing as a silver "deficiency".

Currently, there are no evidence-based medical uses for ingested colloidal silver. There are no clinical studies in humans demonstrating effectiveness, and a few reports of toxicity. The U.S. National Center for Complementary and Alternative Medicine has issued an advisory indicating that the marketing claims made about colloidal silver are scientifically unsupported, and that the silver content of marketed supplements varies widely and can pose risks to the consumer.

Use as water disinfectant

Electrolytically dissolved silver has been used as a water disinfecting agent. Silver was added as a disinfectant to the drinking water supplies of Russian Mir orbital station and the International Space Station. The World Health Organization includes silver in a colloidal state produced by electrolysis of silver electrodes in water, and colloidal silver in water filters as two of a number of water disinfection methods specified to provide safe drinking water in developing countries. Along these lines, a ceramic filtration system coated with silver particles has been created by Ron Rivera of Potters for Peace and used in developing countries for water disinfection.

Use in horticulture

Silver in ionic solutions like silver thiosulfate and silver nitrate (not suspended elemental silver) has been shown to be an ethylene inhibitor by competing with ethylene for binding sites by the plant receptors. Because of this property, solutions containing silver ions are sometimes used by florists to keep flowers fresh longer . Since ethylene is also involved in the "sexing" of plants, this property of blocking ethylene synthesis is also used for forcing male flowers on female plants. As a result, the use of ionic silver solutions has become popular in cannabis cultivation.

Adverse effects and interactions

Main article: Argyria

Chronic intake of silver products, especially colloidal silver, can result in silver or silver sulfide particles in the skin, a condition known as argyria, one symptom of which is blue or gray discoloration of the skin; similarly, it can lead to silver in the eye (argyrosis) and in other organs. The discoloration occurs when silver is deposited in the skin and then darkened by sunlight, just as silver particles in photographic film darken when exposed to sunlight. Localized argyria can occur as a result of topical use of silver-containing remedies, while generalized argyria results from the ingestion of colloidal silver. Argyria is usually permanent, and there is no known effective treatment; the only practical method of minimizing its cosmetic disfigurement is avoiding the sun. While argyria is usually benign and limited to skin discoloration, there are isolated reports of more serious neurologic, renal, or hepatic complications. A death has been reported in the medical literature as a result of colloidal silver use; in that case, a 71-year-old man developed status epilepticus which the authors felt was due to silver toxicity.

A number of case reports describe argyria after ingestion of colloidal silver marketed as an alternative-medicine treatment. Colloidal silver may theoretically reduce the absorption of some medications, including tetracycline and quinolone antibiotics and penicillamine, thereby reducing the effectiveness of those medications.

Government regulation

In August 1999, the U.S. Food and Drug Administration (FDA) banned colloidal silver sellers from claiming any therapeutic or preventive value for the product, noting that colloidal silver was being marketed for numerous diseases without evidence of safety or effectiveness. The product now has the status of a dietary supplement in the US; it can be promoted with general "structure-function" claims, but cannot be marketed as preventing or treating any illness. Following this ruling, the FDA has issued numerous warnings to Internet sites which have continued to promote colloidal silver as an antibiotic or for other medical purposes.

In 2002, the Australian Therapeutic Goods Administration (TGA) found that there were no legitimate medical uses for colloidal silver and no evidence to support its marketing claims. Given the associated safety risks, the TGA concluded that "efforts should be made to curb the illegal availability of colloidal silver products, which is a significant public health issue."

See also

References

  1. ^ "Colloidal Silver Products". National Center for Complementary and Alternative Medicine. December 2006. Retrieved 2008-10-06.
  2. Berger; et al. "Electrically Generated Silver ions: Quantitative Effects on Bacterial and Mammalian Cells. (Free full text PDF)". American Society for Microbiology. Antimicrobial Agents and Chemotherapy. {{cite journal}}: Explicit use of et al. in: |last= (help) Also at PubMed http://www.ncbi.nlm.nih.gov/pubmed/944551
  3. Hall; et al. "In vitro effects of low intensity direct current generated silver on eukaryotic cells". Journal of Oral and Maxillofacial Surgery Feb 1988. {{cite journal}}: Explicit use of et al. in: |last= (help) Official Journal of the American Association of Oral and Maxillofacial Surgeons.
  4. Tien DC, Tseng KH, Liao CY, Tsung TT (2008). "Colloidal silver fabrication using the spark discharge system and its antimicrobial effect on Staphylococcus aureus". Med Eng Phys. 30 (8): 948–52. doi:10.1016/j.medengphy.2007.10.007. PMID 18069039. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  5. ^ van Hasselt P, Gashe BA, Ahmad J (2004). "Colloidal silver as an antimicrobial agent: fact or fiction?". J Wound Care. 13 (4): 154–5. PMID 15114827. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  6. ^ Chopra, Ian (February 16, 2007). "The increasing use of silver-based products as antimicrobial agents: a useful development or a cause for concern?". Journal of Antimicrobial Chemotherapy. 59: 587. doi:10.1093/jac/dkm006. ISSN doi=10.1093/jac/dkm006. {{cite journal}}: Check |issn= value (help); Missing pipe in: |issn= (help)
  7. ^ "About Herbs: Colloidal Silver". Memorial Sloan-Kettering Cancer Center. 2008-07-25. Retrieved 2008-10-03.
  8. Searle, A.B. (1920). "Chapter VIII: Germicides and Disinfectants". The Use of Colloids in Health and Disease. Gerstein - University of Toronto : Toronto Collection: London Constable & Co.
  9. Roe, A. Legge. "COLLOSOL ARGENTUM AND ITS OPHTHALMIC USES". British Medical Journal (Br Med J). Br Med J 1915, 1, 104 (bmj.1.2820.104): 104.
  10. Macleod, C.E.Alex (February 03, 1912). "ELECTRIC METALLIC COLLOIDS AND THEIR THERAPEUTICAL APPLICATIONS". Lancet. 179 (4614): 322–323. doi:10.1016/S0140-6736(01)66545-0. {{cite journal}}: Check date values in: |date= (help)
  11. Searle, A.B. (1920). "Chapter IX: Colloidal Remedies and Their Uses". The Use of Colloids in Health and Disease. Gerstein - University of Toronto : Toronto Collection: London Constable & Co.
  12. Cantlie, James (November 15, 1913). "SOME RECENT OBSERVATIONS ON SPRUE". British Medical Journal (BMJ) (Br Med J 1913, 2, 1282–1302): 1296–1297.
  13. Fung MC, Bowen DL (1996). "Silver products for medical indications: risk-benefit assessment". J. Toxicol. Clin. Toxicol. 34 (1): 119–26. doi:10.3109/15563659609020246. PMID 8632503.
  14. Tien DC, Tseng KH, Liao CY, Tsung TT (2008). "Colloidal silver fabrication using the spark discharge system and its antimicrobial effect on Staphylococcus aureus". Med Eng Phys. 30 (8): 948–52. doi:10.1016/j.medengphy.2007.10.007. PMID 18069039. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  15. Fung MC, Weintraub M, Bowen DL (1995). "Colloidal silver proteins marketed as health supplements". JAMA. 274 (15): 1196–7. doi:10.1001/jama.274.15.1196. PMID 7563503. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  16. ^ Wadhera A, Fung M (2005). "Systemic argyria associated with ingestion of colloidal silver". Dermatol. Online J. 11 (1): 12. PMID 15748553.
  17. Newman M, Kolecki P (2001). "Argyria in the ED". Am J Emerg Med. 19 (6): 525–6. doi:10.1053/ajem.2001.25773. PMID 11593479. {{cite journal}}: Unknown parameter |month= ignored (help)
  18. ^ "Over-the-counter drug products containing colloidal silver ingredients or silver salts. Department of Health and Human Services (HHS), Public Health Service (PHS), Food and Drug Administration (FDA). Final rule". Fed Regist. 64 (158): 44653–8. 1999. PMID 10558603. {{cite journal}}: Unknown parameter |month= ignored (help)
  19. Spacecraft Water Exposure Guidelines for Selected Contaminants: Volume 1. U.S. National Academy of Sciences. 2004. p. 324.
  20. Solsona, Felipe (2003). "Water Disinfection" (PDF). World Health Organization. {{cite web}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  21. Richmond, Caroline (2008-10-16). "Ron Rivera: Potter who developed a water filter that saved lives in the third world". The Guardian. Retrieved 2009-05-16. {{cite news}}: Cite has empty unknown parameter: |coauthors= (help)
  22. Corbett, Sara (December 24, 2008). "Solution in a Pot". New York Times. Retrieved May 15, 2009.
  23. Committee on Creation of Science-based Industries in Developing Countries, Development, Security, and Cooperation, Policy and Global Affairs, National Research Council of the National Academies, Nigerian Academy of Science. (2007). Mobilizing Science-Based Enterprises for Energy, Water, and Medicines in Nigeria. Washington, D.C: National Academies Press. p. 39. ISBN 0-309-11118-8. {{cite book}}: |author= has generic name (help)CS1 maint: multiple names: authors list (link)
  24. Cassells, A. C. (2006). Dictionary of plant tissue culture. Haworth Press. p. 77. ISBN 1560229195, 9781560229193. {{cite book}}: Check |isbn= value: invalid character (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
  25. Constabel, Friedrich (1994). "1: Initiation, Nutrition, and Maintenance of Plant Cell and Tissue Cultures". Plant Cell and Tissue Culture. Springer. p. 5. ISBN 0792324935. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  26. Taking the mystery out of flower care solutions
  27. Mukerji, K G. (2000). "3: Sexual Differentiation in Higher Plants". Glimpses in Botany. APH Publishing. p. 10. ISBN 8176482048, 9788176482042. {{cite book}}: Check |isbn= value: invalid character (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
  28. Lansdown AB (2006). "Silver in health care: antimicrobial effects and safety in use". Curr Probl Dermatol. 33: 17–34. PMID 16766878.
  29. ^ Brandt D, Park B, Hoang M, Jacobe HT (2005). "Argyria secondary to ingestion of homemade silver solution". J. Am. Acad. Dermatol. 53 (2 Suppl 1): S105–7. doi:10.1016/j.jaad.2004.09.026. PMID 16021155. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  30. ^ Okan D, Woo K, Sibbald RG (2007). "So what if you are blue? Oral colloidal silver and argyria are out: safe dressings are in". Adv Skin Wound Care. 20 (6): 326–30. doi:10.1097/01.ASW.0000276415.91750.0f. PMID 17538258.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  31. Mirsattari SM, Hammond RR, Sharpe MD, Leung FY, Young GB (2004). "Myoclonic status epilepticus following repeated oral ingestion of colloidal silver". Neurology. 62 (8): 1408–10. PMID 15111684. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  32. Case reports of argyria related to colloidal silver products include:
  33. "Colloidal Silver Not Approved". U.S. Food and Drug Administration. 2007-02-12. Retrieved 2008-09-22.
  34. "FDA Warning Letter" (PDF). U.S. Food and Drug Administration. 2001-03-13. Retrieved 2008-09-22.
  35. "Regulation of colloidal silver and related products". Australian Therapeutic Goods Administration. 2005-11-09. Retrieved 2008-09-22.

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