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# Zinc (Elemental)
## Overview
Zinc is an essential trace element involved in DNA synthesis, protein metabolism, and immune function. It is commonly administered as a salt (e.g., zinc sulfate, gluconate, acetate). "Elemental zinc" refers to the actual amount of zinc in the compound; note that bioavailability differs by salt form.
## Primary Indications
* Treatment/prevention of zinc deficiency.
* Parenteral nutrition (trace element supplementation).
* Wilson’s disease (zinc acetate).
* Adjunctive therapy for acute diarrhea (WHO/UNICEF guidelines).
## Adult Dosing
* **Dietary Deficiency:** 25–50 mg elemental zinc daily.
* **Wilson’s Disease:** 50 mg elemental zinc (as acetate) 3 times daily, taken at least 1 hour before or after meals.
* **Maximum Daily Intake (Tolerable Upper Limit):** 40 mg/day for healthy adults to avoid copper deficiency. Higher doses for therapeutic indications require clinical supervision.
## Pediatric Dosing
* **Dietary Deficiency:** 0.5–1 mg/kg/day elemental zinc.
* **Acute Diarrhea (WHO Recommendation):** 6 months to 5 years: 20 mg elemental zinc daily for 10–14 days. Infants <6 months: 10 mg daily for 10–14 days.
* **Maximum Daily Intake:** Varies by age; generally avoid exceeding 4 mg/day (1–3 years) to 34 mg/day (14–18 years) for long-term supplementation.
## Dose Adjustments
* **Renal Impairment:** No formal standardized adjustment, but monitor for accumulation in severe impairment.
* **Hepatic Impairment:** Generally safe, but monitor in patients with cirrhosis.
* **Copper Status:** Reduce or discontinue dose if signs of hypocaremia develop.
## Contraindications
* Hypersensitivity to zinc salts.
* Acute supplementation is not recommended in the absence of deficiency except for specific therapeutic indications (e.g., Wilson’s disease, diarrhea).
## Adverse Effects
* **Common:** Nausea, vomiting, epigastric pain, diarrhea, metallic taste.
* **Serious:** Copper deficiency (manifesting as sideroblastic anemia or neutropenia) with chronic high-dose use.
## Key Drug Interactions
* **Tetracyclines/Fluoroquinolones:** Zinc complexes with these antibiotics, significantly reducing their absorption. Space doses by at least 2–4 hours.
* **Penicillamine:** Zinc decreases absorption of penicillamine; space by at least 2 hours.
* **Iron Supplements:** Concurrent high-dose oral iron may inhibit zinc absorption.
## Monitoring
* **Serum Zinc levels:** Often unreliable; assess clinical symptoms (dermatitis, alopecia, impaired wound healing).
* **Copper studies:** Monitor serum ceruloplasmin and copper levels during long-term high-dose therapy (>40 mg/day) to prevent deficiency.
## Clinical Pearls
* **Bioavailability:** Zinc acetate is often considered to have better bioavailability and fewer GI side effects than sulfate.
* **Food interaction:** High-fiber or high-phytate foods (whole grains, legumes) significantly decrease zinc absorption.
* **Administration:** If GI upset occurs, zinc can be taken with food, although this may reduce absorption.
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**Educational Disclaimer:** This information is for educational purposes only. Dosing and clinical protocols may vary by institution and patient-specific factors. Always verify current prescribing information, local pediatric protocols, and safety guidelines before administration.
