© 2003-17 Susan K. Mikota DVM and Donald C. Plumb, Pharm.D. Published by
Elephant Care International
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Elephant specific information, if available, is in blue.
Chemistry – Zinc acetate occurs as white crystals or granules. It has a faint acetous odor and effloresces slightly. One gram is soluble in 2.5 ml of water and in 30 ml of alcohol.
Zinc sulfate occurs as a colorless granular powder, small needles, or transparent prisms. It is odorless but has an astringent metallic taste. 1.67 grams are soluble in one ml of water. Zinc sulfate is insoluble in alcohol and contains 23% zinc by weight.
Storage/Stability/Compatibility – Store zinc acetate crystals in tight containers. Unless otherwise recommended by the manufacturer, store zinc sulfate products in tight containers at room temperature.
Pharmacology – Zinc is a necessary nutritional supplement; it is required by over 200 metalloenzymes for proper function. Enzyme systems that require zinc include alkaline phosphatase, alcohol dehydrogenase, carbonic anhydrase and RNA polymerase. Zinc is also necessary to maintain structural integrity of cell membranes and nucleic acids. Zinc dependent physiological processes include sexual maturation and reproduction, cell growth and division, vision, night vision, wound healing, immune response, and taste acuity.
When administered orally, large doses of zinc can inhibit the absorption of copper.
Uses/Indications – Zinc sulfate is used systemically as a nutritional supplement in a variety of species. Oral zinc acetate has been shown to reduce copper toxicity in susceptible dog breeds (Bedlington Terriers, West Highland White Terriers) with hepatic copper toxicosis. Zinc sulfate is also used topically as an astringent and as weak antiseptic both for dermatologic and ophthalmic conditions.
Pharmacokinetics – About 20-30% of dietary zinc is absorbed, principally from the duodenum and ileum. Bioavailability is dependent upon the food in which it is present. Phytates can chelate zinc and form insoluble complexes in an alkaline pH. Zinc is stored mostly in red and white blood cells, but is also found in the muscle, skin, bone, retina, pancreas, liver, kidney and prostate. Elimination is primarily via the feces, but some is also excreted by the kidneys and in sweat. Zinc found in feces may be reabsorbed in the colon.
Contraindications/Precautions/Reproductive Safety – Zinc supplementation should be carefully considered before administering to patients with copper deficiency.
No documented adverse effects associated with zinc therapy during pregnancy apparently exist, but neither have adequate, well-controlled studies been performed.
Adverse Effects/Warnings – Large doses may cause GI disturbances. Hematologic abnormalities may occur with large doses, particularly if a coexistent copper deficiency exists.
Overdosage/Acute Toxicity – Signs associated with overdoses of zinc, include hemolytic anemia, hypotension, jaundice, vomiting and pulmonary edema. Suggestions for treatment of overdoses of oral zinc, include removing the source, dilution with milk or water and chelation therapy using edetate calcium disodium (Calcium EDTA). Refer to that monograph for possible doses and usage information.
Drug Interactions – Large doses of zinc can inhibit copper absorption in the intestine. If this interaction is desirable, separate copper and zinc supplements by at least two hours. Penicillamine and ursodiol may potentially inhibit zinc absorption; clinical significance is not clear. Zinc salts may chelate oral tetracycline and reduce its absorption; separate doses by at least two hours. Zinc salts may reduce the absorption of some fluroquinolones (e.g., enrofloxacin).
For zinc-related dermatoses:
a) Rapidly growing dogs: 10 mg/kg day PO of zinc sulfate. (Willemse 1992)
b) For zinc-responsive dermatoses found in Siberian huskies, Alaskan malamutes, Great Danes, and Doberman pinschers: Zinc sulfate: 10 mg/kg PO with food either once daily or divided q12h. Alternatively, zinc methionine: 2 mg/kg PO once daily. Correct any dietary imbalances (high calcium and phytate). Lifetime therapy usually required. If vomiting occurs, lower dose or give with food.
For syndrome seen in puppies: Dietary corrections alone usually resolve the syndrome, but zinc supplementation as above, can expedite process. Some puppies require supplementation until maturity. (Kwochka 1994)
For adjunctive therapy of severe hepatic lipidosis:
a) 7 -10 mg/kg PO once daily, in B-Complex mixture if possible. (Center 1994)
a) an Asian elephant with skin lesions responded to 2 g zinc carbonate /day (Schmidt, 1989).
a) Schmidt,M.J. 1989. Zinc deficiency, presumptive secondary immune deficiency and hyperkeratosis in an Asian elephant: A case report. Proc.Am.Assoc.Zoo Vet. Pages: 23-31
Abstract: Zinc deficiency in an Asian elephant caused a secondary immune deficiency, and skin lesions which included superinfected vesiculobullae above the toenails and hyperkeratosis on the extensor surfaces of both elbows and on the tail. The elephant responded to therapy with an immune stimulant drug, but the chronic recurring skin lesions did not heal until after zinc supplementation was added to the diet. Additional excerpt: Dramatic improvement was noted within two weeks after the elephant was started on 2 g zinc carbonate per day. Lesions resolved by eight weeks. Subsequently, the dietary zinc level was adjusted from 21.56 mg/kg of feed to 53.6 mg/kg of feed on a dry matter basis.
Monitoring Parameters/Client Information – See above
Dosage Forms/Preparations/FDA Approval Status/Withholding Times –
Veterinary-Approved Products: None (for systemic use).
Several vitamin/mineral supplements contain zinc, however.
Zinc Acetate is available from chemical supply houses.
Zine Sulfate Injection: 1 mg/ml (as sulfate) in 10 & 30 ml vials; 5 mg/ml in 5 & 10 ml vials; 1 mg/ml (as 2.09 mg chloride) in 10 ml vials; Zinca-Pak® (Smith & Nephew SoloPak); generic, (Rx)
Zinc Sulfate Oral Tablets 66 mg (15 mg zinc); 110 mg (25 mg zinc); 200 mg (45 mg zinc); Zinc 15® (Mericon);Orazinc® (Mericon); Generic; (OTC)
Zinc Sulfate Oral Capsules 220 mg (50 mg zinc); Orazinc® (Mericon), Verazinc® (Forest), Zinc-220® (Alto), Zincate® (Paddock), generic; (Rx or OTC depending on product)
Zinc sulfate is also available in topical ophthalmic preparations.