GALZIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for GALZIN (GALZIN).
Galzin (zinc acetate) acts by blocking the absorption of copper from the gastrointestinal tract and promoting fecal excretion of copper, thereby reducing copper accumulation in tissues. It induces metallothionein in intestinal cells, which binds copper and prevents its entry into the portal circulation.
| Metabolism | Zinc acetate is excreted primarily in the feces (90%) and to a lesser extent in urine. It does not undergo significant hepatic metabolism; it is absorbed in the small intestine and transported via albumin. |
| Excretion | Renal: >90% as unchanged drug; biliary/fecal: <5%. |
| Half-life | Terminal half-life 43-63 days (mean 52 days) due to extensive tissue binding; requires 4-6 months to reach steady state. |
| Protein binding | ~90% bound to albumin and alpha-2-macroglobulin. |
| Volume of Distribution | Vd ~1.2-1.5 L/kg; reflects extensive tissue distribution, particularly in liver and brain. |
| Bioavailability | Oral: 20-40% (variable, food decreases absorption); IV: 100%. |
| Onset of Action | Oral: 2-4 weeks for clinical improvement in Wilson disease; IV: Not applicable. |
| Duration of Action | Duration of clinical effect: indefinite with continued dosing; tissue redistribution leads to prolonged action after discontinuation. |
50 mg orally three times daily, taken at least 1 hour before or 2 hours after meals.
| Dosage form | CAPSULE |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment. For severe renal impairment (GFR <30 mL/min/1.73 m²), reduce dose to 50 mg twice daily. |
| Liver impairment | No dose adjustment required for mild hepatic impairment (Child-Pugh A). Not recommended in moderate to severe hepatic impairment (Child-Pugh B or C) due to lack of data. |
| Pediatric use | Weight-based dosing: 1-2 mg/kg/day divided into 3 doses, not to exceed 50 mg three times daily. Safety and efficacy not established in children <5 years. |
| Geriatric use | No specific dose adjustment required. Start at low end of dosing range and monitor renal function due to age-related decline. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for GALZIN (GALZIN).
| Breastfeeding | Zinc is normally present in breast milk; therapeutic supplementation increases milk zinc concentration. M/P ratio not well characterized for pharmacological doses. Generally considered compatible with breastfeeding at recommended doses, but monitor infant for copper deficiency with prolonged high-dose maternal therapy. |
| Teratogenic Risk | Zinc is an essential trace element; therapeutic zinc supplementation has not been associated with major teratogenicity in human studies. However, excessive zinc intake may impair copper absorption and cause maternal copper deficiency, potentially affecting fetal development. Caution in first trimester due to theoretical risk of zinc-induced copper deficiency. |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to zinc acetate or any component of the formulation.","Patients with known copper deficiency."]
| Precautions | ["Can cause copper deficiency leading to hematologic (e.g., sideroblastic anemia, neutropenia) and neurologic effects (e.g., myelopathy).","Gastric irritation; should be taken with food.","May interact with chelating agents (e.g., penicillamine) and antibiotics (e.g., tetracyclines, fluoroquinolones).","Monitor serum zinc and copper levels regularly.","Use with caution in patients with renal impairment."] |
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| Fetal Monitoring | Monitor maternal serum zinc and copper levels regularly (e.g., every 1-3 months) to maintain zinc within therapeutic range (typically 70-150 µg/dL) and avoid copper deficiency (serum copper <70 µg/dL). Consider fetal ultrasound for growth monitoring if maternal copper deficiency suspected. |
| Fertility Effects | Zinc is essential for normal reproductive function; deficiency may impair fertility. Supplementation in deficient individuals may improve fertility. No known adverse effects on fertility with therapeutic doses; however, zinc-induced copper deficiency can cause hormonal imbalances affecting ovulation and spermatogenesis. |