auranofin
Ridaura

Available forms
Available by prescription only
Capsules: 3 mg

Indications and dosages
 Rheumatoid arthritis, psoriatic arthritis ◇, active systemic lupus erythematosus ◇, Felty’s syndrome ◇. Adults: 6 mg P.O. daily, administered either as 3 mg b.i.d. or 6 mg once daily. After 4 to 6 months, may be increased to 9 mg daily (3 mg t.i.d.). If response remains inadequate after 3 months at 9 mg daily, discontinue drug.

Pharmacodynamics
Antarthritic action: Auranofin suppresses or prevents, but doesn’t cure, adult or juvenile arthritis and synovitis. It is anti-inflammatory in active arthritis. This drug is thought to reduce inflammation by altering the immune system. Auranofin has been shown to decrease high serum levels of immunoglobulins and rheumatoid factors in patients with arthritis. However, the exact mechanism of action remains unknown.

Pharmacokinetics
Absorption: When administered P.O., 25% of the gold in auranofin is absorbed through the GI tract.
Distribution: 60% protein-bound and distributed widely in body tissues. Oral gold from auranofin is bound to a higher degree than gold from the injectable form. Synovial fluid levels are about 50% of blood levels. No correlation between blood-gold levels and safety or efficacy has been determined.
Metabolism: The metabolic fate of auranofin isn’t known, but it’s believed that drug isn’t broken down into elemental gold.
Excretion: 60% of absorbed auranofin (15% of the administered dose) is excreted in urine and the remainder in feces. Average plasma half-life is 26 days, compared with about 6 days for gold sodium thiomalate.

Contraindications and precautions
Contraindicated in patients with history of severe gold toxicity, necrotizing enterocolitis, pulmonary fibrosis, exfoliative dermatitis, bone marrow aplasia, severe hematologic disorders, or history of severe toxicity caused by previous exposure to other heavy metals.
  Use cautiously with other drugs that cause blood dyscrasias or in patients with renal, hepatic, or inflammatory bowel disease; rash; or bone marrow depression. Drug isn’t recommended for use in pregnant women.

Interactions
Drug-drug. Drugs that may cause blood dyscrasias: Cause additive hematologic toxicity. Monitor hematologic studies.

Adverse reactions
CNS: confusion, hallucinations, seizures.
EENT: conjunctivitis.
GI: diarrhea, abdominal pain, nausea, stomatitis, glossitis, anorexia, metallic taste, dyspepsia, flatulence, constipation, dysgeusia, ulcerative colitis.
GU: proteinuria, hematuria, nephrotic syndrome, glomerulonephritis, acute renal failure.
Hematologic: thrombocytopenia (with or without purpura), aplastic anemia, agranulocytosis, leukopenia, eosinophilia, anemia.
Hepatic: jaundice, hepatic dysfunction.
Respiratory: interstitial pneumonitis.
Skin: rash, pruritus, dermatitis, exfoliative dermatitis, urticaria, erythema, alopecia.

Effects on lab test results
• May increase ALT, AST, and alkaline phosphatase levels.
• May increase eosinophil count. May decrease hemoglobin and platelet, granulocyte, and WBC counts.

Overdose and treatment
Overdose may cause severe neurotoxicity.
 In acute overdose, empty gastric contents by induced emesis or gastric lavage. When severe reactions to gold occur, corticosteroids, dimercaprol (a chelating agent), or penicillamine may be given to aid recovery. Prednisone 40 to 100 mg daily in divided doses is recommended to manage severe renal, hematologic, pulmonary, or enterocolitic reactions to gold. Dimercaprol may be used together with steroids to facilitate the removal of the gold when steroid treatment alone is ineffective. Use of chelating agents is controversial, and caution is recommended. Appropriate supportive therapy is indicated, as needed.

Special considerations
• Serum protein-bound iodine test, especially when done by the chloric acid digestion method, gives false readings during and for several weeks after gold therapy. Tuberculin skin test may have an enhanced response. Consider this when interpreting results.
• Monitor CBC, platelet count, urinalysis, and kidney and liver function tests before therapy for baseline and then monthly.
• Discontinue drug if platelet count decreases to below 100,000/mm³.
• Monitor patient for signs of toxicity, which include leukocyte count less than 400/mm³, granulocyte count less than 1,500/mm³, decreased platelet count to 150,000/mm³, proteinuria, hematuria, pruritus, rash, stomatitis, and persistent diarrhea.
• Advise monitoring for uncontrolled diarrhea; dose reduction or temporary discontinuance of drug may relieve diarrhea.
• When switching from injectable gold, initial dose is 6 mg P.O. daily.
• To encourage patient compliance with follow-up, initial prescription should be for 2 weeks and subsequent prescriptions for 1 month.
Pregnant patients
• There are no adequate and controlled studies, but clinical experience doesn’t indicate evidence of adverse effects on the fetus.
Breast-feeding patients
• Drug isn’t recommended for use during breast-feeding.
Pediatric patients
• Controlled clinical trials for the treatment of juvenile rheumatoid arthritis in children ages 4 to 16 are ongoing. Safe dosage hasn’t been established; use in children isn’t recommended.
Geriatric patients
• Administer usual adult dose. Use cautiously in patients with decreased renal function.

Patient education
• Emphasize importance of monthly follow-up to monitor patient’s platelet count.
• Reassure patient that beneficial drug effect may be delayed for 3 months. However, if response is inadequate after 6 to 9 months, auranofin will probably be discontinued.
• Encourage patient to take drug as prescribed and not to alter the dosage schedule.
• Diarrhea is the most common adverse reaction. Tell patient to continue taking drug if he experiences mild diarrhea; however, tell him to call immediately if blood appears in stool.
• Tell patient to continue taking concomitant drug therapy, such as NSAIDs, if prescribed.
• Dermatitis is a common adverse reaction. Advise patient to report rash or other skin problems immediately.
• Stomatitis is another common adverse reaction. Tell patient that stomatitis is often preceded by a metallic taste and that he should call immediately if this occurs.

Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE THREATENING.
◆ Canada only
◇ Unlabeled clinical use