Review of auranofin, an oral chrysotherapeutic agent

The chemistry, pharmacology, pharmacokinetics, clinical use and efficacy, adverse effects, and dosage of auranofin, an oral chrysotherapeutic agent used in treatment of rheumatoid arthritis, are reviewed. Auranofin is lipid-soluble and is monomeric in solution. It has a modulatory effect on both the humoral and cellular immune systems. Auranofin may be a condition-dependent immunoregulating agent rather than an immunosuppressive agent. It inhibits (1) monocyte-mediated antibody-dependent cellular toxicity, (2) release of enzymes from polymorphonuclear leukocytes that may contribute to the pathogenesis of rheumatoid arthritis, and (3) neutrophil activity. In patients with rheumatoid arthritis, 15-33% of an oral dose of auranofin 6 mg is absorbed. Peak plasma gold concentrations are achieved in one to two hours. Gold is highly protein bound. Elimination occurs through the feces and urine; 73-100% of auranofin gold is excreted. Plasma half-life is three weeks. Patients receiving auranofin 3 mg twice daily for rheumatoid arthritis reported improvement after five weeks of therapy; improvement has also been reported with lower doses. Diarrhea, rashes, and pruritus were the most common adverse effects. Auranofin is safe and effective for short- and long-term treatment of patients with rheumatoid arthritis. Its relative safety and potency compared with injectable gold salts and other drugs need further study.