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# Zinc
## Overview
Zinc is an essential trace element required for protein synthesis, immune function, wound healing, and DNA synthesis. It exists as a cofactor for over 300 enzymes. Elemental zinc content varies significantly by salt (e.g., zinc gluconate, sulfate, acetate).
## Primary Indications
* Treatment and prevention of zinc deficiency.
* Adjunct therapy for pediatric acute diarrhea (WHO/UNICEF recommendation).
* Wilson disease (zinc acetate).
## Adult Dosing
* **Dietary Supplementation:** 15–30 mg elemental zinc daily.
* **Treatment of Deficiency:** 50–100 mg elemental zinc/day (divided doses). *Note: High doses (>40 mg/day) should be limited to short-term use due to copper depletion risk.*
* **Wilson Disease:** 50 mg elemental zinc orally three times daily.
* **Upper Respiratory Infection:** Zinc acetate lozenges (10–15 mg elemental zinc) every 2–3 hours while awake; do not exceed 100 mg elemental zinc/day.
## Pediatric Dosing
* **Acute Diarrhea (WHO Recommendation):** 6 months to 5 years: 20 mg elemental zinc daily for 10–14 days. Infants <6 months: 10 mg elemental zinc daily.
* **Deficiency:** 0.5–1 mg/kg elemental zinc daily; max dose 40 mg daily.
## Dose Adjustments
* **Renal Impairment:** No formal adjustments, but monitor closely in patients with renal failure.
* **Hepatic Impairment:** Use caution; zinc is excreted primarily via biliary routes.
## Contraindications
* Hypersensitivity to zinc salts.
* Acute supplementation during the initial recovery phase of Wilson disease (chelating agents are preferred).
## Adverse Effects
* **Common:** Nausea, vomiting, abdominal pain, diarrhea, metallic taste.
* **Serious:** Copper deficiency (manifesting as anemia, leukopenia, neutropenia) following chronic high-dose use.
## Key Drug Interactions
* **Antibiotics:** Zinc reduces absorption of tetracyclines and quinolones; space doses by at least 2–4 hours.
* **Penicillamine:** Zinc decreases absorption.
* **Copper:** High zinc intake induces metallothionein, which blocks copper absorption; chronic zinc supplementation requires copper monitoring or supplementation (typically 1–2 mg copper per 30 mg zinc).
## Monitoring
* **Serum Zinc:** Levels can be difficult to interpret due to acute phase reactions (zinc drops during inflammation).
* **Long-term use:** Monitor CBC, differential, and copper/ceruloplasmin levels to screen for drug-induced copper deficiency.
## Clinical Pearls
* **Salt Content:** Zinc gluconate is 14% elemental zinc; zinc sulfate is 23%; zinc acetate is 30%. Always calculate based on *elemental* zinc.
* **Administration:** Take with food if gastric distress occurs, though food (especially phytates/fiber) may reduce absorption.
* **Nasal Safety:** Avoid intranasal zinc products due to reports of permanent anosmia (loss of smell).
* **Dosing Protocols:** Pediatric diarrhea dosing protocols vary by regional public health guidelines; verify local facility protocols.
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*Disclaimer: This information is for educational purposes only. Always verify doses, indications, and contraindications against current clinical guidelines, manufacturer labeling, and institutional prescribing protocols before administration.*
