Zinc Acetate for Metabolic Disorders

INDICATIONS AND USAGE Zinc acetate therapy is indicated for maintenance treatment of patients with Wilson’s disease who have been initially treated with a chelating agent (See PRECAUTIONS: Monitoring Patients ).

DOSAGE AND ADMINISTRATION The recommended adult dose is 50 mg as zinc three times daily (See CLINICAL TRIALS ). Since 25 mg t.i.d. is also an effective dose in children 10 years of age or older or in women who are pregnant, it may be advisable to use a dose of zinc to 25 mg three times a day, as long as the patient is compliant with therapy. The dose can be raised to 50 mg t.i.d. if monitoring indicates a lessening of control (see PRECAUTIONS: Monitoring Patients ). Patients should take zinc acetate on an empty stomach, at least one hour before or two to three hours after meals. For additional information, see PRECAUTIONS .

WARNINGS Copper Deficiency Several post-marketing cases reported that zinc acetate taken over extended periods of time (i.e., months to years) may result in decreased enteral copper absorption and copper deficiency. The cases reported the following complications of copper deficiency: anemia, granulocytopenia, leukopenia, neutropenia, pancytopenia, thrombocytopenia, and myeloneuropathy. If a patient develops signs and/or symptoms of copper deficiency during treatment with zinc acetate, interrupt zinc treatment and measure zinc, 24-hr urinary copper, and non-ceruloplasmin bound copper (NCC) levels. Consider restarting zinc acetate treatment based on periodic monitoring of 24-hr urinary copper and NCC levels. Gastric Ulcer There have been postmarketing reports of gastric ulcers with long-term use of zinc acetate. The cases reported the complications of anemia and gastric ulcer perforation with peritonitis. In some cases, ulcers persisted after treatment until zinc acetate was discontinued. If a patient develops signs and/or symptoms of gastric ulcer during treatment with zinc acetate, discontinue zinc treatment. Most patients showed improvement after cessation of zinc treatment.

Drug Interactions Pharmacodynamic studies in Wilson’s disease patients failed to demonstrate drug interactions between zinc acetate (50 mg t.i.d.) and ascorbic acid (1 g daily), penicillamine (1 g daily), and trientine (1 g daily). Therefore, precautions for zinc acetate effects do not seem necessary when Wilson’s disease patients are taking vitamin C or approved chelating agents. However, no data are available to demonstrate that zinc acetate should be added to other drugs used for the treatment of Wilson’s disease patients or is safe.

ADVERSE REACTIONS The following adverse reactions associated with the use of zinc acetate were identified from postmarketing reports. Because these reactions were reported voluntarily from a population of uncertain size, it is not possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Gastrointestinal disorders: gastric irritation Investigations: elevations of serum alkaline phosphatase, amylase, and lipase lasting from weeks to months suggesting pancreatitis; the levels usually return to high normal within the first one or two years of zinc therapy.