Gold salts are ionic chemical compounds of gold. The term, which is a misnomer, has evolved into a synonym for the gold compounds used in medicine. The application of gold compounds to medicine is called "chrysotherapy" and "aurotherapy." The first reports of research in this area appeared in 1935, primarily to reduce inflammation and to slow disease progression in patients with rheumatoid arthritis. The use of gold compounds decreased since the 1990s because of numerous side effects and monitoring requirements, limited efficacy, and very slow onset of action. Most chemical compounds of gold, including some of the drugs discussed below, are not, in fact, salts but are examples of metal thiolate complexes.
The use of injected gold salts is indicated for rheumatoid arthritis. However, the use of gold is now rare due to numerous side effects, the need for continual patient monitoring, limited efficacy and slow onset of action. The efficacy of orally administered gold is even more limited than injectable gold compounds.
Mechanism in arthritis
The mechanism by which gold drugs affect arthritis is unknown.
Gold salts for rheumatoid arthritis are administered by intramuscular injection but can also be administered orally (although the efficacy is low). Regular urine tests to check for protein (indicating kidney damage) and blood tests are needed.
A 1997 review (Suarez-Almazor ME et al.) reports that treatment with intramuscular gold (parenteral gold) reduces disease activity and joint inflammation. Gold salts taken by mouth are less effective than by injection. Three to six months are often required before gold treatment noticeably improves symptoms.
One noticeable side-effect of gold-based therapy is the coloring of the skin in shades of mauve to a purplish dark grey when exposed to sunlight, if the salts are taken on a regular basis over a long period of time . Excessive intake of gold salts while undergoing chrysotherapy result – through complex redox processes – in the saturation by relatively stable gold compounds of skin tissue and organs (as well as teeth and ocular tissue in extreme cases), a condition known as chrysiasis, similar to a certain extent to argyria which is related to silver salts and colloidal silver. Chrysiasis can ultimately lead to acute renal failure (such as tubular necrosis, nephrosis, glomerulitis ), severe heart conditions, hematologic complications (leukopenia, anemia): while some effects can be healed with moderate success, the pigmentation of the skin is considered permanent.
Other side effects
Other side effects of gold salts include kidney damage, itching rash, and ulcerations of the mouth, tongue and pharynx. Approximately 35% of patients discontinue the use of gold salts because of these side effects. Kidney function must be monitored continuously while taking gold salts.
Types of gold salts
- Auranofin (UK & U.S.)
- Aurothioglucose (Gold thioglucose) (U.S.)
- Disodium aurothiomalate
- Sodium aurothiosulfate (Gold sodium thiosulfate)
- Sodium aurothiomalate (Gold sodium thiomalate) (UK)
- Shaw III, C. F. (1999). "Gold-Based Medicinal Agents". Chemical Reviews 99 (9): 2589–600. doi:10.1021/cr980431o. PMID 11749494.
- Forestier J. (1935). "Rheumatoid arthritis and its treatment with gold salts - results of six years experience.". J Lab Clin Med 20: 827–40.
- William O. Foye; Thomas L. Lemke; David A. Williams (1 September 2007). Foye's principles of medicinal chemistry. Lippincott Williams & Wilkins. pp. 989–. ISBN 978-0-7817-6879-5. Retrieved 14 November 2010.
- Bingham, C. Updated, 2012. Rheumatoid Arthritis Treatment. Johns Hopkins Medical. http://www.hopkinsarthritis.org/arthritis-info/rheumatoid-arthritis/ra-treatment/#gold
- Clark P, Tugwell P, Bennett KJ, Bombardier C, Shea B, Wells GA, Suarez-Almazor ME. Injectable gold for rheumatoid arthritis. Cochrane Database of Systematic Reviews 1997, Issue 4. Art. No.: CD000520. doi:10.1002/14651858.CD000520.
- "BMJ case reports: Chrysiasis" http://casereports.bmj.com/content/2009/bcr.07.2008.0417.full
- Drug Reference for EMS Providers, Richard K.Beck, 2002, pp. 164–165: auranofin and Aurothioglucose side effects & overdose
- Auranofin complete list of warnings,precautions and reactions http://www.drugs.com/pro/ridaura.html and various inflammations
- Aurothioglucose Suspension adverse effects : http://www.healthdigest.org/topics/category/979-aurothioglucose-suspension-dosage-interactions-side-effects-how-to-use
- Gold sodium thiomalate: adverse effects including allergy to gold, tolerance to gold decreasing with age, skin and renal complications. http://web.squ.edu.om/med-Lib/MED_CD/E_CDs/Focus%20on%20Nursing%20Pharmacology%202000/mg/gold_sodium_thiomalate_%28gold%29.htm
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- "HMS researchers find how gold fights arthritis: Sheds light on how medicinal metal function against rheumatoid arthritis and other autoimmune diseases." Harvard University Gazette (2006)
- "Aurothioglucose is a gold salt used in treating inflammatory arthritis". MedicineNet.com
- "About gold treatment: What is it? Gold treatment includes different forms of gold salts used to treat arthritis." Washington.edu University of Washington (December 30, 2004)