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# Zinc (Elemental)
## Overview
Zinc is an essential trace element required for protein synthesis, wound healing, immune function, and DNA synthesis. It exists in various salt forms (e.g., gluconate, sulfate, acetate), and dosing must be based on **elemental** zinc content, not the weight of the salt.
## Primary Indications
Treatment and prevention of zinc deficiency; adjunctive therapy for Wilson’s disease (acetate form); management of acuity in pediatric diarrhea (WHO protocols).
## Adult Dosing
* **Dietary Supplementation:** 15–30 mg elemental zinc daily.
* **Deficiency Treatment:** 30–150 mg elemental zinc daily (administered in divided doses).
* **Wilson’s Disease:** 50 mg elemental zinc (as acetate) 3 times daily.
* **Upper Respiratory Infection (Common Cold):** If using lozenges, 75 mg/day started within 24 hours of symptom onset; clinical evidence is mixed and duration should not exceed 1–2 weeks to avoid toxicity.
## Pediatric Dosing
* **Dietary Reference Intake (0–6 months):** 2 mg/day.
* **Dietary Reference Intake (7–12 months):** 3 mg/day.
* **Dietary Reference Intake (1–3 years):** 3 mg/day.
* **Acute Diarrhea (WHO Recommendation):** 10 mg/day (infants <6 months) or 20 mg/day (children >6 months) for 10–14 days.
## Dose Adjustments
* **Renal Impairment:** No specific guidelines; however, zinc is primarily excreted via the GI tract. Use caution in severe impairment due to potential accumulation.
* **Hepatic Impairment:** No dosing adjustments available; monitor liver function if prolonged high-dose therapy is required.
## Contraindications
Hypersensitivity to zinc salts. Avoid excessive prophylactic dosing without documented deficiency.
## Adverse Effects
* **Common:** Nausea, vomiting, diarrhea, epigastric pain, metallic taste.
* **Severe (Chronic overdosage):** Copper deficiency (manifesting as anemia or leukopenia), suppressed immune function, and decreased HDL cholesterol.
## Key Drug Interactions
* **Quinolones/Tetracyclines:** Zinc significantly reduces the oral absorption of these antibiotics. Separate administration by at least 2–4 hours before or 4–6 hours after zinc.
* **Penicillamine:** Zinc decreases the absorption of penicillamine; separate dosing by 2 hours.
* **Copper:** High-dose zinc induces metallothionein, which traps copper in the gut, leading to dietary copper deficiency.
## Monitoring
* **Long-term high-dose therapy:** Monitor serum zinc levels, copper levels, and serum ceruloplasmin.
* **Hematology:** CBC to rule out sideroblastic anemia or neutropenia indicative of copper deficiency.
## Clinical Pearls
* **Salt Variations:** 100 mg of zinc sulfate contains ~23 mg of elemental zinc; 100 mg of zinc gluconate contains ~14 mg of elemental zinc. Always verify the elemental content on the label.
* **Administration:** Take with food if gastric irritation occurs, although absorption may be slightly reduced.
* **Toxicity:** Excessive oral intake over long periods is the primary cause of iatrogenic copper deficiency.
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**Disclaimer:** This information is for educational purposes only. Always consult current institutional protocols, the package insert, and clinical decision support tools (e.g., Lexicomp, UpToDate) before prescribing or administering any medication. Dosing may vary based on local clinical practice guidelines.
