Zeuterin (''zū-tur-in'') is the trade name of an injectable product containing
zinc gluconate
Zinc gluconate is the zinc salt of gluconic acid. It is an ionic compound consisting of two anions of gluconate for each zinc(II) cation. Zinc gluconate is a popular form for the delivery of zinc as a dietary supplement providing 14.35% element ...
and the amino acid
arginine
Arginine is the amino acid with the formula (H2N)(HN)CN(H)(CH2)3CH(NH2)CO2H. The molecule features a guanidinium, guanidino group appended to a standard amino acid framework. At physiological pH, the carboxylic acid is deprotonated (−CO2−) a ...
, which is used for
sterilizing young male dogs without the removal of the testicles.
The product is injected directly into the testicle,
where the zinc gluconate destroys the
sperm
Sperm (: sperm or sperms) is the male reproductive Cell (biology), cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm ...
and causes
inflammation
Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and loss of function (Latin ''calor'', '' ...
, which leads to
fibrosis
Fibrosis, also known as fibrotic scarring, is the development of fibrous connective tissue in response to an injury. Fibrosis can be a normal connective tissue deposition or excessive tissue deposition caused by a disease.
Repeated injuries, ch ...
and causes sterility.
Sperm production continues for up to 60 days after product administration, and in some dogs does not stop completely, although the product is 99.6% effective when given to dogs aged 3-10 months of age.
Following administration, the testicles atrophy; the degree of atrophy may vary noticeably between testicles.
The male hormone,
testosterone
Testosterone is the primary male sex hormone and androgen in Male, males. In humans, testosterone plays a key role in the development of Male reproductive system, male reproductive tissues such as testicles and prostate, as well as promoting se ...
, is produced in limited quantities following treatment with Zeuterin, but after two years, testosterone production is similar to that in untreated dogs.
The continuing presence of testosterone means that, unlike surgical castration, chemical castration does not remove the risk of testosterone-associated disease, such as prostatic disease.
This method of chemical castration is
contraindicated
In medicine, a contraindication is a condition (a situation or factor) that serves as a reason not to take a certain medical treatment due to the harm that it would cause the patient. Contraindication is the opposite of indication, which is a rea ...
in cases of undescended testicles (
cryptorchidism
Cryptorchidism, also known as undescended testis, is the failure of one or both testes to descend into the scrotum. The word is . It is the most common birth defect of the male genital tract. About 3% of full-term and 30% of premature infant boy ...
), or if
scrotal
In most terrestrial mammals, the scrotum (: scrotums or scrota; possibly from Latin ''scortum'', meaning "hide" or "skin") or scrotal sac is a part of the external male genitalia located at the base of the penis. It consists of a sac of skin c ...
dermatitis
Dermatitis is a term used for different types of skin inflammation, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened ...
or testicular disease is present.
If the product is not injected correctly, scrotal ulceration and swelling may occur.
The manufacturer, Ark Sciences, certifies veterinarians to use Zeuterin after they have completed a 5-hour course regarding the correct location and manner to inject the drug.
In the
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
, this product was approved by the
Food and Drug Administration
The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respo ...
in 2003, under the trade name Neutersol, and was marketed from 2003 to 2005 by Pet Healthcare International.
In 2005, Pet Healthcare International severed ties with its manufacturing partner Addison Biologicals, and production of the drug stopped.
Ark Sciences acquired the intellectual property to Neutersol, rebranded it as Zeuterin, and relaunched it in 2014.
In 2016, Ark Sciences suspended distribution of Zeuterin.
Outside of the United States, Zeuterin is known by the trade name Esterilsol.
Zeuterin is based work done by Mostafa S. Fahim to develop a "drug, herein called Kastrin" for use on mammals: "the present treatment can be used on male sheep, pigs, horses and other similar mammals having scrotal testes, including human males."
[ Injectable male animal sterilant for selectively controlling the function of testes, US Patent 4156427A]
References
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Dog medications