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AHFS/Drugs.com International Drug Names
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ATCvet code
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Legal status
  • Veterinary use only
  • 3-[5-(4-Chlorophenyl)-1-(4-methoxyphenyl)pyrazol-3-yl]-N-hydroxy-N-methylpropanamide
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Chemical and physical data
Formula C20H20ClN3O3
Molar mass 385.85 g·mol−1
3D model (JSmol)
  • CN(C(=O)CCc1cc(n(n1)c2ccc(cc2)OC)c3ccc(cc3)Cl)O
  • InChI=1S/C20H20ClN3O3/c1-23(26)20(25)12-7-16-13-19(14-3-5-15(21)6-4-14)24(22-16)17-8-10-18(27-2)11-9-17/h3-6,8-11,13,26H,7,12H2,1-2H3 X mark.svgN
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Tepoxalin, marketed under the brand name Zubrin [1] among many others, is a non-steroidal anti-flammatory drug (NSAIDs) generally used in veterinary medicine to reduce swelling in animals with osteoarthritis. [1] In rare circumstances, Tepoxalin can also be used in human pharmacology to relieve pain caused by musculoskeletal conditions such as arthritis and hip dysplasia. [2]


In 1997, the drug was patented for veterinary use, replacing isoxazole for treating inflammation. [3] In 2017, the drug was withdrawn from the American market and can no longer be administered in the United States. [3]

Tepoxalin (C20H20ClN3O3) is produced by the condensation of a carboxyl group and an amino group. [1] There are many perspectives on whether the consumption of Tepoxalin on its own is more effective than combining it with other antihistamines, but when applied in veterinary medicine, Tepoxalin is regularly synthesised with other antihistamines. [1]


The Committee for Medicinal Products for Veterinary Use (CVMP) approves Tepoxalin to be used as a drug for animals to reduce inflammation and pain control. [3] Additionally, in Europe, Tepoxalin is approved by the EU Community Register of Medicinal Products and European Medicines Agency in the product categories of Veterinary Drug and Veterinary Pharmacotherapeutic Group categorised into the Musculo-skeletal System subcategory. [4]

Tepoxalin was first medically approved in the United States in 1998. The drug was taken off the market in 2017 and cannot be administered in the United States. [4] However, it still has Food and Drug Administration (FDA) approval. [4]

On the 4 September 2017, an application was submitted to the European Medicines Agency (EMEA) asking for an extension of marketing authorisation for Tepoxalin. [3] The EMEA criticised the quality, safety and efficacy data submitted and the application was declined. [3]

Pharmacology and biochemistry

Tepoxalin (C20H20ClN3O3) is produced by the condensation of a carboxyl group of 3-[5-(4-chlorophenyl)-1-(4-methoxyphenyl)pyrazol-3-yl] propanoic acid and an amino group of N-methylhydroxylamine. [3]  Condensation is a chemical reaction in which two or more molecules merge into form a larger molecule, with the simultaneous loss of a small molecule such as water or methanol. [3]

The drug works as a nonsteroidal anti-inflammatory drug (NSAID) to suppress both cyclooxygenase and lipoxygenase. [5] Cyclooxygenase and lipoxygenase produces COX-2 and 5-LOX enzymes respectively, these enzymes activate the swelling and inflammation that causes pain in animals. Tepoxalin is an inhibitor which blocks out theses enzymes to reduce the swelling and inflammation.  Additionally, it can be also used as a “dual-action” inhibitor to additionally suppress leukotriene and prostaglandin (E2). [5] Leukotriene and prostaglandin are also enzymes that activates inflammation in the body. [6]

Tepoxalin is produced into white, flavourless tablets that rapidly disintegrate when consumed by an animal. These tasteless tablets are branded as Zubrin on the market. [4] After consumption, Zubrin has a half-life of 120 minutes in the plasma (cytoplasm; the main part of the capsule) itself, whereas the entire metabolite (entirety of the capsule) has a half-life of 13 hours. [4] It is therefore usually prescribed to be taken once a day. [3]

Canine and feline uses

Available in an oral formulation, Tepoxalin is used to treat osteoarthritis in canine and feline species. [4] The use of Tepoxalin was more effective than the NSAID (nonsteroidal anti-flammatory drug), carprofen when administered in canines. As a result, the usage of carprofen was replaced with Tepoxalin in 1998. [7]

Tepoxalin can only be administered to dogs that weigh 3 pounds (1.4 kg) or larger at a dose of 10–20 mg/kg at a daily schedule. [6] The approximate duration of complete treatment is at most 14 days. [1] If treated for a prolonged period of time (more than 180 days), it may result in gastrointestinal irritation and gastric ulceration. The plasma concentration of Tepoxalin when administered varies between every dog, so there is no difference in administering between fed or fasted canines. [1]  However, there is a low water solubility and a high fat solubility, it is often prescribed to fed canines rather than fasted as this is more effective for Tepoxalin. [7]

In felines, Tepoxalin has an inhibitory action on COX-1 and 5-LOX enzymes in contrary in canines, Tepoxalin causes inhibition for COX-2 and 5-LOX enzymes. For felines, Tepoxalin is prescribed in doses between 5 and 10 mg/kg once daily for 3 consecutive days. Additionally, Tepoxalin can only be prescribed to felines over the weight of 3 pounds (1.4 kg). [8] When Tepoxalin is administered in cats, a drunken-like state afflicting the central nervous system has been recorded on rare occasions. [8]

Ill cat injected with NSAID, Tepoxalin Sick cat installing a catheter.jpg
Ill cat injected with NSAID, Tepoxalin

Equine use

When administered for horses, the formulation can be in a paste, powder or feed-in form which can be fed orally or it can be injected through the vein but no other place in the equine body, as it can cause tissue damage. [9] However, if Tepoxalin is injected repeatedly in the vein for a prolonged period of time, it can also cause tissue damage and edema (trapped fluid in tissue). [9]

Chronic inflammatory diseases are the most common diseases in horses. Phenylbutazone was formerly used as treatment, but when administered to horses at high doses, it can develop ulcers of the glandular stomach, oral cavity and colon. [10] Due to the major adverse effects of phenylbutazone, the replacement for Tepoxalin was made to be administered to horses to reduce muscular pain in 2003. [9]

In horses, the drug is intravenously administered at 10 mg/kg on a daily dose for 10 days respectively. [9] Doses may be doubled or tripled to treat severe pain, such as laminitis. The plasma (cytoplasm; the main part of the capsule) half-life of Tepoxalin is 4–8 hours, although the inflammatory entire metabolite (entirety of the capsule) half-life is 24 hours, so single dosing is more efficient for horses. When given at reasonable doses, the drug is non-toxic even when used repeatedly. [9]

Case of laminitis Laminitis embedding hc biovision.jpg
Case of laminitis

Adverse effects

There is a high incidence of adverse reports received for Tepoxalin by the Centre of Veterinary Medicine . [11] Common side effects of the consumption of Tepoxalin include vomiting, diarrhoea, blood in faeces, loss of appetite, fatigue, thirst, an increase in urination and behavioural changes. [7] In older and sensitive animals, loss of hair and abrasion of the skin may occur. [10] The drug cannot be used by animals during breeding, pregnancy or lactation as the drug can affect the foetus or infants. [10] In animals with a history of internal bleeding or low blood pressure, it can result in perforation of the stomach walls or intestinal mucosa. [10]

Older dogs are more prone to the adverse effects. [11] When administered to male canines, there are no effects to the male's fertility. However, when a female canine is treated during the organogenetic period, it may result in embryo foetal toxicity. [10] The outcome of this toxicity is a major reduction in foetal weight, incomplete formation of various bones and other skeletal malformations. In extreme cases,  it can result in the death of the foetus. [10]

Overdose can occur if administered in an excessive large dose. Signs of overdose or toxicity in canines and felines include tremors, seizures, abnormal behaviour, vomiting and weakness. [3]

Related Research Articles


Ketoprofen is one of the propionic acid class of nonsteroidal anti-inflammatory drugs (NSAID) with analgesic and antipyretic effects. It acts by inhibiting the body's production of prostaglandin.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are members of a drug class that reduces pain, decreases fever, prevents blood clots, and in higher doses, decreases inflammation. Side effects depend on the specific drug but largely include an increased risk of gastrointestinal ulcers and bleeds, heart attack, and kidney disease.

Ibuprofen Medication used for treating pain, fever, and inflammation

Ibuprofen is a medication in the nonsteroidal anti-inflammatory drug (NSAID) class that is used for treating pain, fever, and inflammation. This includes painful menstrual periods, migraines, and rheumatoid arthritis. It may also be used to close a patent ductus arteriosus in a premature baby. It can be used by mouth or intravenously. It typically begins working within an hour.

Diclofenac Nonsteroidal anti-inflammatory drug

Diclofenac, sold under the brand name Voltaren among others, is a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain and inflammatory diseases such as gout. It is taken by mouth, rectally in a suppository, used by injection, or applied to the skin. Improvements in pain last for as much as eight hours. It is also available in combination with misoprostol in an effort to decrease stomach problems.

Naproxen A nonsteroidal anti-inflammatory drug (NSAID) used to treat pain, menstrual cramps, inflammatory diseases such as rheumatoid arthritis, gout, and fever

Naproxen, sold under the brand name Aleve among others, is a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain, menstrual cramps, inflammatory diseases such as rheumatoid arthritis, gout and fever. It is taken orally. It is available in immediate and delayed release formulations. Onset of effects is within an hour and last for up to twelve hours.


Phenylbutazone, often referred to as "bute", is a nonsteroidal anti-inflammatory drug (NSAID) for the short-term treatment of pain and fever in animals.

COX-2 inhibitors are a type of nonsteroidal anti-inflammatory drug (NSAID) that directly targets cyclooxygenase-2, COX-2, an enzyme responsible for inflammation and pain. Targeting selectivity for COX-2 reduces the risk of peptic ulceration and is the main feature of celecoxib, rofecoxib, and other members of this drug class.

Meloxicam Nonsteroidal anti-inflammatory drug (NSAID)

Meloxicam, sold under the brand name Mobic among others, is a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain and inflammation in rheumatic diseases and osteoarthritis. It is used by mouth or by injection into a vein. It is recommended that it be used for as short a period as possible and at a low dose.


Ketorolac, sold under the brand name Toradol among others, is a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain. Specifically it is recommended for moderate to severe pain. Recommended duration of treatment is less than six days. It is used by mouth, by nose, by injection into a vein or muscle, and as eye drops. Effects begin within an hour and last for up to eight hours.


Flunixin is a nonsteroidal anti-inflammatory drug (NSAID), analgesic, and antipyretic used in horses, cattle and pigs. It is often formulated as the meglumine salt. In the United States, it is regulated by the U.S. Food and Drug Administration (FDA), and may only be lawfully distributed by order of a licensed veterinarian. There are many trade names for the product.

Carprofen Nonsteroidal anti-inflammatory drug

Carprofen, marketed under many brand names worldwide, is a nonsteroidal anti-inflammatory drug (NSAID) that veterinarians prescribe as a supportive treatment for various conditions in animals. It provides day-to-day treatment for pain and inflammation from various kinds of joint pain as well as post-operative pain. Carprofen reduces inflammation by inhibition of COX-1 and COX-2; its specificity for COX-2 varies from species to species.

Deracoxib Chemical compound

Deracoxib is a nonsteroidal anti-inflammatory drug (NSAID) of the coxib class, used in dogs to treat pain associated with osteoarthritis, or to prevent pain following orthopedic or dental surgery. It is available as beef-flavored tablets.

A prostaglandin antagonist is a hormone antagonist acting upon one or more prostaglandins, a subclass of eicosanoid compounds which function as signaling molecules in numerous types of animal tissues.

Meclofenamic acid

Meclofenamic acid is a drug used for joint, muscular pain, arthritis and dysmenorrhea. It is a member of the anthranilic acid derivatives class of nonsteroidal anti-inflammatory drugs (NSAIDs) and was approved by the US FDA in 1980. Like other members of the class, it is a cyclooxygenase (COX) inhibitor, preventing the formation of prostaglandins.


Maropitant (INN; trade name: Cereniasə-REE-nee-ə), used as maropitant citrate (USAN), is a neurokinin-1 (NK1) receptor antagonist which was developed by Zoetis specifically for the treatment of motion sickness and vomiting in dogs. It was approved by the FDA in 2007 for use in dogs and in 2012 for cats.


Difloxacin (INN), marketed under the trade name Dicural, is a second-generation, synthetic fluoroquinolone antibiotic used in veterinary medicine. It has broad-spectrum, concentration dependent, bactericidal activity; however, its efficacy is not as good as enrofloxacin or pradofloxacin.

Feline idiopathic cystitis (FIC) or feline interstitial cystitis or cystitis in cats, is one of the most frequently observed forms of feline lower urinary tract disease (FLUTD). Feline cystitis means "inflammation of the bladder in cats". The term idiopathic means unknown cause; however, certain behaviours have been known to aggravate the illness once it has been initiated. It can affect both males and females of any breed of cat. It is more commonly found in female cats; however, when males do exhibit cystitis, it is usually more dangerous.

Polysulfated glycosaminoglycan Injectable drug

Polysulfated glycosaminoglycan (PSGAG), sold under the brand name Adequan, is an injectable drug for dogs and horses that is used to alleviate the lameness, pain, and lowered range of motion caused by arthritis. It is made of repeat disaccharide units, and is similar to glycosaminoglycans already present in the cartilage; PSGAG thus easily integrates itself there. In vitro studies have shown it to inhibit the enzymes that degrade cartilage and bone, as well as suppress inflammation and stimulate the synthesis of replacement cartilage. While it can cause an increased risk of bleeding, it is relatively safe and has a high LD50. PSGAG is one of the most widely prescribed joint treatments for horses.

Balanced anesthesia Anesthetic technique

Balanced anesthesia is a anesthetic method for surgical patients during their operation, which was proposed by John Lundy in 1926.The purpose of balanced anesthesia is not only to be less dangerous than using only one drug to make patients general anesthesia but also to minimise the potential adverse side effects which may cause by the anesthetic agents. The concept of balanced anesthesia is that applying two or more narcotic drugs or techniques in order to help patients to ease pain, relax the muscles and have autonomous reflection suppression. In other words, it is an anesthesia method to maintain stable vital signs. According to patients’ status of significant organs, general condition and compensatory capacity of bodies, anesthetist needs to make use of adequate types, appropriate amounts of agents and the accurate anesthesia method, which will promote the surgery be both successful and efficient in a further way.


Grapiprant is a small molecule drug that belongs in the piprant class. This analgesic and anti-inflammatory drug is primarily used as a pain relief for mild to moderate inflammation related to osteoarthritis in dogs. Grapiprant has been approved by the FDA's Center for Veterinary Medicine and was categorized as a non-cyclooxygenase inhibiting non-steroidal anti-inflammatory drug (NSAID) in March 2016.


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