Gold salts are a group of complex chemical compounds containing gold, historically used in medicine. Their medical application is sometimes called chrysotherapy or aurotherapy. While their use has evolved, gold salts hold a significant place in the history of treating certain inflammatory conditions.
Chemical Composition and Properties
Gold salts are compounds where gold is bonded to other elements, often forming an ionic structure. Examples include gold sodium thiomalate, aurothioglucose, and auranofin. Gold sodium thiomalate and aurothioglucose contain gold in a thiolate complex, where gold is linked to a sulfur-containing organic molecule. Auranofin is an S-glycosyl compound where gold is coordinated to a sulfur atom within a sugar derivative.
These compounds typically appear as white to yellowish-white powders and are often very soluble in water, especially for injectable forms. For instance, gold sodium thiomalate readily dissolves in water, forming colorless to pale yellow solutions. This solubility aids their preparation and delivery in medical settings.
Therapeutic Applications
Historically, gold salts were primarily used in the treatment of rheumatoid arthritis (RA), a chronic autoimmune condition affecting the joints. They are classified as disease-modifying antirheumatic drugs (DMARDs) because they aim to slow the disease’s progression rather than just alleviating symptoms. Gold salts were once a cornerstone therapy for RA, with 70% to 75% of patients showing a response to treatment. They were also explored for other rheumatologic conditions like psoriatic arthritis, juvenile idiopathic arthritis, lupus erythematosus, and Sjögren’s syndrome.
The exact mechanism by which gold salts exert their therapeutic effects is not fully understood, but it is believed to involve modulating immune responses and reducing inflammation. Gold compounds may interfere with the activity of immune cells such as macrophages and lymphocytes, inhibiting their function and reducing the production of inflammatory chemicals. They might also decrease oxidative stress and inhibit certain enzymes involved in the inflammatory process. Despite their effectiveness for many years, the use of gold salts has declined significantly since the 1990s due to the development of newer, more targeted therapies with fewer side effects.
Administration and Potential Effects
Gold salts can be administered through different routes depending on the specific compound. Gold sodium thiomalate and aurothioglucose are typically given as intramuscular injections, often in the buttocks. Auranofin is an orally administered gold compound, taken as capsules. Treatment protocols often involve initial low doses that are gradually increased, with therapeutic effects sometimes taking several weeks or months to become noticeable.
Gold salts are associated with a range of potential side effects. Common effects include skin rashes, itching, and mouth sores. Gastrointestinal issues such as diarrhea, nausea, and abdominal cramps can also occur. More serious, though less frequent, side effects involve kidney problems, such as protein in the urine (proteinuria), and abnormalities in blood cell counts, including a decrease in white blood cells or platelets. Regular monitoring through blood tests and urinalysis is necessary during treatment to detect and manage adverse reactions promptly.