gold sodium thiomalate
Aurolate

Available forms
Available by prescription only
Injection: 50 mg/ml with benzyl alcohol

Indications and dosages
 Rheumatoid arthritis, psoriatic arthritis ◇, Felty’s syndrome ◇. Adults: Initially, 10 mg I.M.; then 25 mg in second week and continued for a third dose the following week. Continue until 1 g (cumulative) has been given, unless toxicity occurs. If improvement occurs without toxicity before initial 1-g dose, a maintenance dosage of 25 to 50 mg every other week for 2 to 20 weeks may be started. Then continue to every third and then every fourth week indefinitely. Weekly injections may be restarted any time, if needed. If patient doesn’t respond after reaching initial 1-g dose, then discontinue therapy, give 25 to 50 mg I.M. for another 10 weeks, or increase dose by 10 mg q 1 to 4 weeks (maximum dose per injection is 100 mg).
Children: 10-mg test dose; then 1 mg/kg weekly. Continue as listed for adults. Maximum single dose for children younger than age 12 is 50 mg.
 Palindromic rheumatism ◇. Adults: Initially, 10 to 15 mg I.M. weekly until 1-g dose is reached.
 Pemphigus ◇. Adults: Initially, 10 mg I.M.; then 25 mg I.M. for second week followed by 50 mg I.M. weekly. When patient is off corticosteroid therapy, maintenance dosage of 25 to 50 mg I.M. q 2 weeks may be administered.

Pharmacodynamics
Antarthritic action: Gold sodium thiomalate is thought to be effective against rheumatoid arthritis by altering the immune system to reduce inflammation. Although the exact mechanism remains unknown, these compounds have reduced serum levels of immunoglobulins and rheumatoid factors in patients with arthritis.

Pharmacokinetics
Absorption: Absorption is rapid.
Distribution: Higher tissue levels occur with parenteral gold salts, with a mean steady state plasma level of 1 to 5 mcg/ml. Drug is distributed widely throughout the body in lymph nodes, bone marrow, kidneys, liver, spleen, and tissues. About 85% to 90% is protein-bound.
Metabolism: Not broken down into its elemental form. The half-life with cumulative dosing is 14 to 40 days.
Excretion: About 70% is excreted in the urine, 30% in feces.

Contraindications and precautions
Contraindicated in patients hypersensitive to drug; those with hepatitis, exfoliative dermatitis, or a history of severe toxicity from previous exposure to gold or heavy metals; and patients with severe uncontrollable diabetes, renal disease, hepatic dysfunction, uncontrolled heart failure, marked hypertension, systemic lupus erythematosus, colitis, or Sjögren’s syndrome. Also contraindicated in patients with urticaria, eczema, hemorrhagic conditions, or severe hematologic disorders and in those who have recently received radiation therapy.

Interactions
Drug-drug. Drugs known to cause blood dyscrasias: Causes additive risk of hematologic toxicity. Avoid use together.
Drug-lifestyle. Sun or ultraviolet light exposure: May cause photosensitivity reactions. Advise patient to take precautions.

Adverse reactions
CNS: confusion, hallucinations, seizures.
CV: bradycardia, hypotension.
EENT: corneal gold deposition, corneal ulcers.
GI: metallic taste, stomatitis, diarrhea, anorexia, abdominal cramps, nausea, vomiting, ulcerative enterocolitis.
GU: proteinuria, nephrotic syndrome,nephritis, acute tubular necrosis, hematuria, acute renal failure.
Hematologic: thrombocytopenia (with or without purpura), aplastic anemia, agranulocytosis, leukopenia, eosinophilia, anemia.
Hepatic: hepatitis, jaundice.
Skin: diaphoresis, photosensitivity, rash, dermatitis, erythema, exfoliative dermatitis.
Other: anaphylaxis, angioedema.

Effects on lab test results
• May increase BUN, creatinine, and liver enzyme levels.
• May increase eosinophil count. May decrease hemoglobin, hematocrit, and platelet, granulocyte, and WBC counts.

Overdose and treatment
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 corticosteroids to facilitate removal of the gold when corticosteroid treatment alone is ineffective.

Special considerations
 ALERT Administer all gold salts I.M., preferably intragluteally. Normal color of drug is pale yellow; don’t use if it darkens.
• Vasomotor adverse effects are more common with gold sodium thiomalate than with other gold salts.
 ALERT Adverse reactions to gold are considered severe and potentially life-threatening.
• Most adverse reactions are readily reversible if drug is discontinued immediately.
• If adverse reactions are mild, some rheumatologists order resumption of gold therapy after 2 to 3 weeks’ rest.
• 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.
• Obtain pregnancy test before starting therapy.
• Obtain patient’s urine for analysis for protein and sediment changes before each injection.
• Monitor CBC and platelet count monthly or before every other injection. Stop drug if platelet count drops below 100,000/mm³, hemoglobin drops from baseline, granulocytes are less than 1,500/mm³, leukocytes are less than 4,000/mm³, or eosinophils are greater than 5%.
• Patient should remain recumbent for 10 to 20 minutes and remain under medical observation for 30 minutes after administration because of possible anaphylactic reaction.
Breast-feeding patients
• Use in breast-feeding women isn’t recommended.
Pediatric patients
• Use in children younger than age 6 isn’t recommended.
Geriatric patients
• Administer usual adult dose. Use cautiously in patients with decreased renal function.

Patient education
• Inform patient that beneficial drug effect may take 3 months.
• Explain that vasomotor adverse reactions-faintness, weakness, dizziness, flushing, nausea, vomiting, diaphoresis-may occur immediately after injection. Advise patient to lie down until symptoms subside.
• Tell patient that stomatitis is commonly preceded by a metallic taste and to report this symptom immediately.
• Advise patient to immediately report rash or other skin problems.

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