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Cronyxin Injection (Canada)

This page contains information on Cronyxin Injection for veterinary use.
The information provided typically includes the following:
  • Cronyxin Injection Indications
  • Warnings and cautions for Cronyxin Injection
  • Direction and dosage information for Cronyxin Injection

Cronyxin Injection

This treatment applies to the following species:
Company: Bioniche Animal Health



Sterile Solution

DIN 02230652

50 mg/mL flunixin (equivalent to 83 mg flunixin meglumine)

For intravenous or intramuscular use in horses and for intravenous use only in cattle.

THERAPEUTIC CLASSIFICATION: Anti-inflammatory; analgesic; antipyretic

STRUCTURAL FORMULA AND CHEMISTRY: Flunixin meglumine is the N-methyl-glucamine salt of (2 (2’-methyl-3’-trifluoromethyl-anilino) nicotinic acid).

Molecular Formula: C14H11F3N2O2•C7H17NO5

Molecular Weight: 491.46


Each millilitre of Cronyxin solution contains 50 mg flunixin (equivalent to 83 mg flunixin meglumine USP), 0.1 mg edetate disodium, 2.2 mg sodium formaldehyde sulfoxylate, 4.0 mg diethanolamine, 207.2 mg propylene glycol, 5.0 mg phenol as preservative, hydrochloric acid to adjust pH and water for injection q.s.

INDICATIONS: Horses: Cronyxin is recommended for the alleviation of inflammation and associated pain in musculoskeletal disorders in the horse. Cronyxin is also recommended for the alleviation of visceral pain associated with colic in the horse.

Cattle: Cronyxin is indicated for the control of pyrexia associated with Bovine Respiratory Disease (BRD), endotoxemia and acute bovine mastitis. Cronyxin is also indicated for the control of inflammation associated with endotoxemia. In clinical studies, flunixin meglumine injectable as an adjunct to antibiotic therapy with oxytetracycline has been demonstrated to control pyrexia associated with bovine respiratory disease.

Clinical Pharmacology

Flunixin meglumine is a potent, non-narcotic, non-steroidal, analgesic agent with anti-inflammatory activity. Antipyretic activity has been demonstrated in cattle and in laboratory animals. It is significantly more potent than pentazocine, meperidine and codeine as an analgesic in the rat yeast paw test.

Horse: Flunixin is four times as potent on a mg per mg basis as phenylbutazone as measured by the reduction in lameness and swelling in the horse. Plasma half-life in horse serum is 1.6 hours following a single dose of 1.1 mg flunixin per kg. Measurable amounts are detectable in horse plasma at 8 hours post injection.

Cattle: Flunixin meglumine is a weak acid (pKa = 5.82) which exhibits a high degree of plasma protein binding (app. 99%). However, free (unbound) drug appears to readily partition into body tissues (Vss predictions range from 297 to 782 mL/kg). Total body water is approximately 570 mL/kg. In cattle, elimination occurs primarily through biliary excretion. This may, at least in part, explain the presence of multiple peaks in the blood concentration/time profile following IV administration.

In healthy cattle, total body clearance has been reported to range from 90 to 150 mL/kg/hr. These studies also report a large discrepancy between the volume of distribution at steady state (Vss) and the volume of distribution associated with the terminal elimination phase (Vβ). This discrepancy appears to be attributable to extended drug elimination from a deep compartment. The terminal half-life has been shown to vary from 3.14 to 8.12 hours.

Model and field studies have shown that flunixin can have short-term effect in the control of some inflammatory factors associated with endotoxemia and irritation (carregeenan).

Flunixin persists in inflammatory tissues and is associated with anti-inflammatory properties which extend well beyond the period associated with detectable plasma drug concentrations. These observations account for the counterclockwise hysteresis associated with flunixin’s pharmacokinetic/pharmacodynamic relationship. Therefore, prediction of drug concentrations based on the estimated plasma terminal half-life will likely underestimate both the duration of drug action and the concentration of drug remaining at the site of activity.

Dosage and Administration

Horses: The recommended dose for musculoskeletal disorders is 1.1 mg flunixin per kg (1 mL/45 kg) of body weight once daily. Treatment may be given by intravenous or intramuscular injection and repeated for up to 5 days. Intravenous studies show onset of activity is within 2 hours. Peak response occurs between 12 and 16 hours and duration of activity is 24 to 36 hours following intravenous and intramuscular administration.

The recommended dose for the alleviation of pain associated with equine colic is 1.1 mg flunixin per kg of body weight. Intravenous administration is recommended for prompt relief. Should colic symptoms recur, treatment may be repeated as necessary. Clinical studies show that pain symptoms were alleviated in 37% of treated horses within 15 minutes, and 74% within 30 minutes. The cause of colic should be determined and treated with concomitant therapy.

Cattle: The recommended dose for control of pyrexia associated with bovine respiratory disease and endotoxemia and control of inflammation associated with endotoxemia in cattle is 2.2 mg flunixin per kg (2 mL/45 kg) given by slow intravenous administration once a day for up to 3 days. The total daily dose should not exceed 2.2 mg flunixin per kg of body weight. Avoid rapid intravenous administration of the drug. Twenty-four (24) hours after administration, check if animal is febrile. Readminister only if the fever is 104°F (40°C) or higher.

The recommended dose for control of pyrexia associated with acute bovine mastitis is 2.2 mg flunixin per kg of body weight given as a single intravenous injection. Administer slowly.

CONTRA-INDICATIONS: Horses: Do not administer intra-arterially. Inadvertent intra-arterial injection may cause adverse reactions. Signs can be ataxia, incoordination, hyperventilation, hysteria, and muscle weakness. Signs are transient and disappear without antidotal medication within a few minutes. Do not use in horses showing hypersensitivity to flunixin meglumine.

Cattle: Do not administer intra-arterially. Inadvertent intra-arterial injection may cause adverse reactions. Do not use in cattle showing hypersensitivity to flunixin meglumine. The drug is contraindicated in animals with hepatic disease, renal and cardiovascular impairment, gastro-intestinal ulceration and/or platelet disorders. It is also contraindicated in dehydrated animals.

CAUTIONS: The use of NSAIDs may be associated with gastro-intestinal, hepatic and renal toxicity. Patients at greatest risk for renal toxicity are those that are dehydrated, on concomitant diuretic therapy or those with renal, cardiovascular, and/or hepatic dysfunction Concurrent administration of potentially nephrotoxic drugs should be carefully approached. NSAIDs may inhibit prostaglandins that maintain normal homeostatic function. Such prostaglandin effects may result in clinically significant disease in patients with underlying or pre-existing disease that has not been previously diagnosed. Due to the potential for NSAIDs to induce gastro-intestinal ulceration, concomitant use of this drug with other anti-inflammatory drugs, such as other NSAIDs and corticosteroids should be avoided.

With the exception of the antibiotic oxytetracycline in cattle, studies to determine the activity of flunixin meglumine when administered concomitantly with other drugs have not been conducted. Drug compatibility should be monitored closely in patients requiring adjunctive therapy.

Discontinue use if hematuria or fecal blood are observed. Avoid rapid intravenous administration of the drug.

Horses: The effect of flunixin meglumine on reproduction in horses has not been determined. Studies on reproduction in rats and rabbits have shown no teratogenicity.

Cattle: Do not use in bulls intended for breeding as reproductive effects of Cronyxin in this class of cattle have not been investigated. NSAIDs are known to have potential effects on both parturition and the estrous cycle. There may be a delay in the onset of estrus if flunixin is administered during the prostaglandin phase of the estrous cycle. The effects of flunixin on imminent parturition have not been evaluated in a controlled study. NSAIDs are known to have the potential to delay parturition through a tocolytic effect. Do not exceed the recommended dose.

Adverse Reactions

During clinical studies no significant side effects were reported when the drug was injected slowly. In cattle, a temporary head thrashing can occur if the drug is injected too rapidly.

TOXICITY: No toxic effects were observed in rats given intramuscular flunixin 4 mg/kg/day for 28 days. No adverse effects were seen in dogs given a single intramuscular injection of 50 mg flunixin per kg. Higher doses resulted in salivation, panting, emesis and tremors. No toxic effects were observed in monkeys given intramuscular doses between 3 and 30 mg flunixin per kg per day for 28 days. Horse: Prolonged parenteral treatment in horses at 4.4 mg flunixin per kg body weight showed no untoward effects. Cattle: No flunixin-related changes (adverse reactions) were noted in cattle administered a 1X (2.2 mg flunixin per kg) dose for 9 days (three times the maximum recommended duration for bovine respiratory disease and endotoxemia and nine times the maximum recommended duration for acute bovine mastitis). Toxicity, such as blood in feces and/or urine, manifested itself at moderately elevated doses (3X and 5X) when flunixin was administered daily for 9 days (three times the maximum recommended duration for bovine respiratory disease and endotoxemia and nine times the maximum recommended duration for acute bovine mastitis).


Treated cattle must not be slaughtered for use in food for at least 6 (six) days after the latest treatment with this drug. Milk taken from treated animals within 36 hours after the latest treatment must not be used in food. Not for use in dry dairy cows or in veal calves. A withdrawal period has not been established in pre-ruminating calves. This drug is not to be administered to horses that are to be slaughtered for food. KEEP OUT OF REACH OF CHILDREN


Store between 15°C and 30°C (59°F and 86°F).

PRESENTATION: Cronyxin Injection 50 mg flunixin/mL (equivalent to 83 mg of flunixin meglumine/mL) is available in 100 mL multidose vials.

Manufactured by: Cross Vetpharm Group Ltd., Broomhill Road, Tallaght Dublin 24

Distributed by: Bioniche Animal Health Canada Inc., P.O. Box 1570, Belleville, ON Canada K8N 5J2

Date: February 10/12

NAC No.: 12150075

Distributed by VETOQUINOL N.-A. INC.
Telephone:   450-586-2252
Order Desk:   800-363-1700
Fax:   450-586-4649
Every effort has been made to ensure the accuracy of the Cronyxin Injection information published above. However, it remains the responsibility of the readers to familiarize themselves with the product information contained on the Canadian product label or package insert.

Copyright © 2019 Animalytix LLC. Updated: 2019-09-30