Chrysotherapy is the use of gold salts to treat inflammatory diseases, most notably rheumatoid arthritis. Also called aurotherapy or simply gold therapy, it was for decades a cornerstone of rheumatoid arthritis management before newer drugs largely replaced it. Gold salts work by suppressing parts of the immune system that drive chronic joint inflammation, and while their use has declined significantly, they remain a recognized treatment option.
How Gold Salts Work in the Body
Gold salts reduce inflammation by blocking cells from releasing chemicals that damage joint tissue. One key action is inhibiting the production of prostaglandins, signaling molecules that promote swelling, pain, and stiffness. Because rheumatoid arthritis involves an immune system that essentially attacks its own joints, gold therapy aims to interrupt that cycle at the cellular level.
The precise immunological mechanisms are still not fully mapped out. Researchers have studied gold’s interactions with the immune system for decades, and in vitro and in vivo experiments have produced somewhat conflicting results. What’s clear from clinical experience is that gold salts slow joint destruction and reduce symptoms in many patients, even if the exact pathway remains debated.
Two Forms: Injections and Oral
Gold therapy comes in two main forms. The injectable version, gold sodium thiomalate, is given as an intramuscular shot. It absorbs rapidly, reaching peak blood levels within 3 to 6 hours. The oral form, auranofin, is taken as a daily pill, with effective doses in clinical trials falling around 6 to 9 mg per day.
The two forms differ meaningfully in how the body handles them. Injectable gold follows a three-phase decay pattern in the bloodstream, with a terminal half-life averaging 12.5 days. About 35% of an intravenous dose is excreted through urine within ten days, with another roughly 9% eliminated through stool via bile. Absorption from intramuscular injection can vary quite a bit between individuals, ranging from about 64% to complete absorption. This long half-life and variable absorption help explain why gold therapy requires careful, ongoing monitoring.
What Conditions It Treats
Rheumatoid arthritis is the primary indication. For many years, gold therapy was the go-to treatment for patients with progressive rheumatoid disease that wasn’t responding to basic anti-inflammatory drugs. It falls into the category of disease-modifying antirheumatic drugs (DMARDs), meaning it doesn’t just mask symptoms but actually slows the underlying disease process that erodes joints over time.
Gold has also been used in Felty’s syndrome, a complication of rheumatoid arthritis involving an enlarged spleen and low white blood cell counts. Its use beyond rheumatoid conditions, however, has always been limited.
Side Effects and Risks
Gold therapy carries a real risk of side effects, which is one reason its use requires close medical supervision. The most common problems in the first three months are skin rashes, mouth ulcers, and proteinuria (protein spilling into the urine, a sign of kidney stress). In a large study tracking toxicity over time, the incidence of rash was about 9.8 episodes per 10,000 patient-months during the first three months, with mouth ulcers at 4.0 and proteinuria at 1.8 per 10,000 patient-months.
The encouraging finding from long-term data is that these side effects tend to decrease over time. Patients who tolerate gold well through the first six months can generally continue treatment for up to three years or longer with an increasing margin of safety for skin, mouth, and kidney problems. The exception is thrombocytopenia, a drop in platelet counts that can impair blood clotting. This risk does not appear to decline with continued use, making regular blood monitoring essential throughout treatment.
A rare but distinctive side effect is chrysiasis, a permanent blue-gray discoloration of the skin caused by gold deposits. It’s cosmetically troubling but not medically dangerous.
Monitoring During Treatment
If you’re on gold therapy, expect regular lab work. Before starting, your doctor will order a complete blood count with differential, platelet count, liver function tests, and urinalysis. These tests check for preexisting kidney disease or blood abnormalities that would make gold therapy too risky.
Once treatment begins, the monitoring schedule depends on the form you’re taking. For injectable gold, blood counts and urinalysis are typically checked before every injection during the initial phase, then every one to three months once you’re on a stable maintenance dose. For oral auranofin, these labs are done monthly. Liver enzymes are checked every one to two months regardless of the form. The goal is to catch drops in platelet or white blood cell counts, rising protein in the urine, or liver stress before they become serious problems.
Where Gold Therapy Stands Today
Chrysotherapy has largely been overtaken by methotrexate and biologic DMARDs, which offer more predictable results and, in many cases, a more manageable side effect profile. Most rheumatologists today reach for methotrexate as a first-line DMARD, with biologics added when the response is insufficient.
That said, gold hasn’t disappeared entirely. A 48-week randomized, placebo-controlled trial found that adding intramuscular gold to methotrexate produced significant clinical improvement in patients whose arthritis wasn’t adequately controlled on methotrexate alone. This suggests gold still has a role as an add-on therapy for certain patients, particularly those who haven’t responded well to standard regimens. Its efficacy still appeals to some clinicians, even as the overall trend continues moving toward newer agents.