Usage
- Zinc acetate is primarily indicated for the maintenance treatment of Wilson’s disease, a genetic disorder characterized by excessive copper accumulation in the body. It is used after initial chelation therapy to prevent copper reaccumulation. It can also be used to treat zinc deficiency.
- Pharmacological classification: Mineral supplement, chelating agent (in the context of Wilson’s disease).
- Mechanism of action: Zinc acetate blocks copper absorption in the intestines and promotes its excretion. It induces the production of metallothionein, a protein that binds to copper within the intestinal cells. This prevents copper from entering the bloodstream and facilitates its elimination through the feces.
Alternate Names
- Zinc diacetate
- Brand names: Galzin, Wilzin
How It Works
- Pharmacodynamics: Zinc acetate exerts its therapeutic effect by reducing copper absorption and increasing its excretion. In Wilson’s disease, this helps prevent the toxic buildup of copper in vital organs like the liver and brain.
- Pharmacokinetics:
- Absorption: Absorbed in the small intestine, absorption is reduced when taken with food.
- Distribution: Primarily stored in skeletal muscle and bone.
- Metabolism: Not extensively metabolized.
- Elimination: Excreted primarily in feces and to a lesser extent in urine.
- Mode of action: Zinc induces the synthesis of metallothionein in the intestinal cells. Metallothionein has a high affinity for copper. The copper bound to metallothionein is not absorbed and is eliminated when the intestinal cells are shed. This reduces the net uptake of copper from the diet.
- Receptor binding, enzyme inhibition, or neurotransmitter modulation: Zinc acetate’s primary mechanism does not involve receptor binding, direct enzyme inhibition, or neurotransmitter modulation. Its action focuses on inducing metallothionein production.
- Elimination pathways: Primarily fecal excretion through the shedding of intestinal cells containing copper-bound metallothionein; minor renal excretion.
Dosage
Standard Dosage
Adults:
- Wilson’s Disease: 50 mg elemental zinc (equivalent to approximately 150 mg zinc acetate) three times daily. A lower dose of 25 mg elemental zinc three times daily may be used if the patient is compliant with therapy and copper levels are well-controlled. The maximum dose is 50 mg five times daily.
Children:
- Wilson’s Disease:
- 1 to 6 years: 25 mg twice daily.
- 6 to 16 years (under 57 kg): 25 mg three times daily.
- 16 years and older or body weight over 57 kg: 50 mg three times daily.
- Zinc Deficiency: Based on age and Recommended Dietary Allowance (RDA) for elemental zinc:
- 0-6 months: 2 mg/day
- 7-12 months: 3 mg/day
- 1-3 years: 3 mg/day
- 4-8 years: 5 mg/day
- 9-13 years: 8 mg/day
- 14-18 years (Males): 11mg/day, (Females): 9mg/day.
Special Cases:
- Elderly Patients: Similar to adult dosing, but initiate at a lower dose and adjust based on clinical response and monitoring of zinc levels.
- Patients with Renal Impairment: No specific dose adjustments are available, caution is recommended.
- Patients with Hepatic Dysfunction: No specific dose adjustments for Wilson’s disease, as the medication is used to treat a hepatic condition. For zinc deficiency, adjust dose as needed based on zinc level monitoring.
- Patients with Comorbid Conditions: Consider the impact of comorbid conditions on copper and zinc metabolism, and adjust the dosage based on individual patient needs.
Clinical Use Cases
Zinc acetate’s clinical use is primarily focused on Wilson’s disease management. There are no specific dosage guidelines for its use in clinical settings like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations. Zinc acetate is not indicated for these cases.
Dosage Adjustments
Dose adjustments may be necessary based on therapeutic monitoring of copper levels (for Wilson’s disease) or serum zinc levels (for zinc deficiency). Pregnancy may require dose reduction.
Side Effects
Common Side Effects
- Gastric irritation (nausea, vomiting, stomach cramps). This can be minimized by taking the medication with a small amount of protein-rich food or between meals.
Rare but Serious Side Effects
- Anemia (monitor hemoglobin levels).
- Liver toxicity (monitor liver function tests).
- Leukopenia and neutropenia.
- Elevated gastric pH.
- Copper deficiency may occur, especially in breastfeeding infants.
Long-Term Effects
- Chronic complications are primarily related to uncontrolled copper levels in Wilson’s disease, not specifically due to zinc acetate itself.
Adverse Drug Reactions (ADR)
- Symptoms suggesting severe liver toxicity (jaundice, severe fatigue) require immediate attention.
Contraindications
- Hypersensitivity to zinc acetate.
Drug Interactions
- Tetracycline and quinolone antibiotics: Reduced absorption of these antibiotics. Separate doses by at least 2 hours.
- Penicillamine: May decrease the effectiveness of zinc acetate.
- Iron: May decrease the absorption of both zinc and iron.
- Phosphorus-containing medications: Reduced zinc acetate absorption. Separate doses.
- Foods high in calcium or phytates may decrease zinc absorption. Take zinc acetate at least 1 hour before or 2-3 hours after meals.
Pregnancy and Breastfeeding
- Pregnancy: Zinc acetate may be used during pregnancy if the benefits outweigh the risks. Dose adjustments may be necessary. Consult with a healthcare professional before use during pregnancy.
- Breastfeeding: Breastfeeding is not recommended while taking zinc acetate due to the risk of zinc-induced copper deficiency in the infant. Copper status in breastfeeding infants should be monitored closely.
Drug Profile Summary
- Mechanism of Action: Induces metallothionein production, reducing copper absorption and increasing excretion.
- Side Effects: Nausea, vomiting, stomach cramps, anemia, liver toxicity (rare).
- Contraindications: Hypersensitivity.
- Drug Interactions: Tetracyclines, quinolones, penicillamine, iron, phosphorus-containing medications.
- Pregnancy & Breastfeeding: Use with caution during pregnancy if clearly needed; breastfeeding not recommended.
- Dosage: Adults: 50 mg elemental zinc three times daily. Children: Dose varies with age.
- Monitoring Parameters: Copper levels (24-hour urinary copper), serum zinc levels, liver function tests, complete blood count.
Popular Combinations
Zinc acetate is usually used as monotherapy for maintenance treatment of Wilson’s disease, after initial chelation therapy.
Precautions
- General Precautions: Monitor copper and zinc levels regularly. Evaluate liver function and complete blood counts periodically.
- Specific Populations: See section “Dosage - Special Cases.”
- Lifestyle Considerations: Alcohol consumption may exacerbate zinc deficiency. Advise patients to follow a balanced diet.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Zinc acetate?
A: For Wilson’s disease, adults typically take 50 mg elemental zinc (equivalent to approximately 150 mg zinc acetate) three times daily. Pediatric doses vary depending on age and weight. For zinc deficiency, doses are based on RDA for age.
Q2: How should zinc acetate be taken?
A: On an empty stomach, at least 1 hour before or 2-3 hours after meals. If gastric irritation occurs, it may be taken with a small amount of protein-rich food or between meals.
Q3: What are the common side effects of zinc acetate?
A: The most common side effects are gastrointestinal, including nausea, vomiting, and stomach cramps.
Q4: Can zinc acetate be used during pregnancy?
A: It can be used if clearly needed, but careful monitoring of copper status in both the mother and the fetus is essential. The dose may need to be adjusted.
Q5: Is it safe to breastfeed while taking zinc acetate?
A: Breastfeeding is not recommended while taking zinc acetate due to the risk of copper deficiency in the infant.
Q6: How does zinc acetate interact with other medications?
A: It can interact with tetracycline and quinolone antibiotics, penicillamine, iron, and phosphorus-containing medications. These interactions can reduce the absorption of these medications or decrease the effectiveness of zinc acetate. Consult the Drug Interactions section for details.
Q7: How is Wilson’s disease monitored during zinc acetate therapy?
A: Regular monitoring includes 24-hour urinary copper excretion, serum ceruloplasmin, and liver function tests.
Q8: What should I do if my patient experiences gastrointestinal side effects?
A: Suggest taking zinc acetate with a small amount of food or between meals. If side effects persist, consider dose adjustment.
Q9: What if a dose is missed?
A: Skip the missed dose and take the next dose at the regular scheduled time. Do not double the dose.
