Gold sodium thiosulfate is a gold-containing compound used in two main contexts: as an injectable treatment for rheumatoid arthritis and as a standard substance in skin patch testing to detect gold allergy. It belongs to a class of medications known as gold salts, which have been used in medicine since the late 1920s. If you’ve come across this term, it was likely on a patch test result or in connection with arthritis treatment.
Why Gold Is Used in Medicine
The medical use of gold compounds, sometimes called chrysotherapy, dates back to 1929, when French physician Jacques Forestier demonstrated that ionic gold compounds could relieve joint pain in rheumatoid arthritis patients and sometimes produce complete remission. Over the following decades, gold salts became a mainstay of rheumatoid arthritis treatment, with roughly 70 to 75% of patients responding positively.
Gold salts have also been tested for psoriatic arthritis, juvenile idiopathic arthritis, lupus, and Sjögren syndrome. Their use has declined significantly since newer biologic drugs became available, but gold compounds remain relevant in allergy testing and are still prescribed in some cases.
How Gold Salts Work Against Inflammation
Gold compounds target the inflammatory pathways that drive joint damage in rheumatoid arthritis. They block the activation of a key signaling complex called NF-kB, which normally triggers the production of inflammatory enzymes in the joints. They also interfere with pro-inflammatory signaling molecules like TNF-alpha, IL-6, and IL-1beta, all of which play central roles in the chronic inflammation that erodes cartilage and bone.
The leading theory for how gold achieves this is that gold atoms bind to sulfur-containing amino acids in the active sites of these inflammatory proteins, essentially disabling them. This broad anti-inflammatory effect is what made gold salts effective for so many patients, but it’s also what makes them capable of affecting healthy tissues and causing side effects.
Gold Sodium Thiosulfate in Allergy Testing
One of the most common reasons people encounter gold sodium thiosulfate today is through patch testing for contact allergies. Dermatologists apply a small amount of the compound to the skin, typically on the back, and check for a reaction after 48 to 96 hours. A positive reaction, usually redness and small blisters at the test site, indicates sensitivity to gold.
Gold allergy is more common than most people expect. When gold sodium thiosulfate was added to a standard patch test series, 8.6% of 823 consecutive patients with suspected contact allergies tested positive. People with occupational exposure to gold dust or gold leaf are particularly at risk, but gold jewelry is the most common everyday source of exposure. A positive result doesn’t always mean you’ll react to gold jewelry, since the gold in most jewelry is alloyed with other metals, but it can explain persistent skin irritation around rings, necklaces, or piercings.
How the Body Processes Gold Compounds
Injectable gold salts are absorbed into the bloodstream and cleared slowly. After entering the blood, gold concentrations decline in three distinct phases, with a terminal half-life of about 12.5 days. This means gold stays in the body for weeks after each injection. The kidneys handle most of the elimination: about 35% of an intravenous dose appears in the urine within ten days, while roughly 9% exits through the stool via bile secretion.
Absorption from intramuscular injections is variable. In a small pharmacokinetic study, one subject absorbed 100% of an intramuscular dose while another absorbed only 64%, which partly explains why patients can respond differently to the same treatment schedule.
Side Effects and Risks
Gold salt therapy carries a meaningful risk of side effects, and this is one of the main reasons it fell out of favor as newer arthritis drugs arrived. The most common problems are skin reactions (rashes, mouth sores, and dermatitis) and kidney effects. Mild protein in the urine is frequently seen during treatment, while full nephrotic syndrome is less common but more serious. In one long-term series, about 45% of patients eventually stopped treatment because of rash, and 15% stopped because of kidney-related protein loss in the urine.
Blood cell abnormalities can also occur at any point during treatment or even after stopping. Low white blood cell counts and low platelet counts are the most common blood-related complications, though they happen less often than skin or kidney problems. Rarer but more concerning reactions include lung inflammation, liver problems involving blocked bile flow, and nerve damage in the hands and feet. Most side effects are mild and reversible, but deaths have been reported, usually from severe blood cell abnormalities.
Monitoring During Treatment
Because gold salts can affect the blood and kidneys, patients receiving chrysotherapy need regular lab work. Standard monitoring includes blood counts and urine tests at baseline, then every two weeks early in treatment, and every one to two months once a stable dose is reached. This schedule helps catch dropping blood counts or rising protein in the urine before they become dangerous.
Interestingly, measuring the actual concentration of gold in the blood hasn’t proven useful for predicting whether the treatment is working or whether side effects will develop. Most studies have found no reliable link between gold blood levels and clinical outcomes, so doctors rely on symptoms and standard lab tests instead.
Who Should Avoid Gold Salt Therapy
Gold salts are generally avoided in people with pre-existing kidney disease, since impaired kidneys clear the compound more slowly and raise the risk of toxicity. Liver disease, heart disease, high blood pressure, and conditions involving fluid retention are also concerns because gold compounds can cause the body to hold onto extra water. People with a history of sulfite allergy or asthma may be at higher risk for adverse reactions. Gold therapy is also typically avoided during pregnancy due to the potential for fluid-related complications.