Everything you need to know about Prevail Flunixin 50mg (250 ml)

If you’re a horse or cattle owner, it’s important to have the right medication on hand to alleviate pain and treat musculoskeletal disorders. Prevail Flunixin 50mg (250 ml) is a trusted option that can provide relief for your animals. In this article, we’ll dive deeper into the uses, dosage, precautions, and potential side effects of this medication. Let’s get started!

Understanding the Recommended Dosage

For Horses

When it comes to musculoskeletal disorders in horses, the recommended dosage of Prevail Flunixin is 0.5 mg per pound (1 mL/100 lbs) of bodyweight once daily. Administration can be either intravenous or intramuscular, and treatment can be repeated for up to 5 days. Studies have shown that the medication starts working within 2 hours, with the peak response occurring between 12 and 16 hours. The effects can last for 24-36 hours.

For the alleviation of pain associated with equine colic, the recommended dosage is also 0.5 mg per pound of bodyweight. Intravenous administration is recommended for prompt relief. Clinical studies have indicated that pain can be alleviated in less than 15 minutes in many cases. Treatment can be repeated if signs of colic recur. However, it’s important to identify and treat the underlying cause of the colic with concomitant therapy.

For Cattle

In the case of cattle, the recommended dosage is 1.1 to 2.2 mg/kg (0.5 to 1 mg/lb; 1 to 2 mL per 100 lbs) given by slow intravenous administration. It can be administered once a day as a single dose or divided into two doses administered at 12-hour intervals for up to 3 days. The total daily dose should not exceed 2.2 mg/kg (1.0 mg/lb) of bodyweight. It’s crucial to avoid rapid intravenous administration of the drug.

Safety Precautions and Contraindications

Prevail Flunixin is a powerful medication, and as such, there are some precautions and contraindications that you should be aware of.


When used as directed, there are no known contraindications for horses. However, intra-arterial injection should be avoided, as it can lead to adverse reactions such as ataxia, incoordination, hyperventilation, hysteria, and muscle weakness. These signs are transient and typically disappear within a few minutes without the need for antidotal medication. It’s also important not to use the medication in horses showing hypersensitivity to flunixin meglumine.

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Similarly, there are no known contraindications for cattle when Prevail Flunixin is used as directed. However, it should not be used in animals showing hypersensitivity to flunixin meglumine, and caution should be exercised when renal impairment or gastric ulceration is suspected.

Residue Warnings

If you have cattle, it’s essential to be aware of the residue warnings associated with Prevail Flunixin. Cattle must not be slaughtered for human consumption within 4 days of the last treatment. Additionally, milk taken during treatment and for 36 hours after the last treatment should not be used for food. This medication is not suitable for use in dry dairy cows. Please note that a withdrawal period has not been established for this product in preruminating calves, and it should not be used in calves intended for veal. Lastly, it’s important to know that Prevail Flunixin is not intended for use in horses intended for food.

Precautions and Potential Side Effects

As with any medication, there are precautions and potential side effects to consider.

Prevail Flunixin belongs to a class of drugs known as cyclo-oxygenase inhibitory NSAIDs, which may be associated with gastrointestinal and renal toxicity. The sensitivity to these adverse effects can vary among patients. Patients at the greatest risk for renal toxicity are those who are dehydrated, on concomitant diuretic therapy, or have renal, cardiovascular, and/or hepatic dysfunction.

Since many NSAIDs, including Prevail Flunixin, have the potential to induce gastrointestinal ulceration, it’s important to avoid or closely monitor concomitant use with other anti-inflammatory drugs such as other NSAIDs and corticosteroids.

Safety and Effect on Pregnancy


The effects of Prevail Flunixin on pregnancy in horses have not been determined. Additionally, studies to determine the activity of Prevail Flunixin when administered with other drugs have not been conducted. Therefore, it’s crucial to monitor drug compatibility closely in patients requiring adjunctive therapy.


For cattle intended for breeding, Prevail Flunixin should not be used, as the reproductive effects have not been thoroughly investigated. NSAIDs, including flunixin, are known to have potential effects on both parturition and the estrous cycle. If flunixin is administered during the prostaglandin phase of the estrous cycle, there may be a delay in the onset of estrus. The effects of flunixin on imminent parturition have not been evaluated in a controlled study, but NSAIDs are known to have the potential to delay parturition through a tocolytic effect. It’s important to adhere to the recommended dosage and not exceed it.

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Ensuring Safety and Minimizing Side Effects

Safety is of utmost importance when using any medication, and the same applies to Prevail Flunixin.


Extensive safety studies have been conducted with horses, demonstrating that a three-fold intramuscular dose of 1.5 mg/lb of bodyweight daily for 10 consecutive days is safe. No significant changes were observed in hematology, serum chemistry, or urinalysis values. Intravenous dosages of 0.5 mg/lb daily for 15 days, 1.5 mg/lb daily for 10 days, and 2.5 mg/lb daily for 5 days also produced no changes in blood or urine parameters. Following the recommended dose of 0.5 mg/lb administered intramuscularly, no injection site irritation was observed. However, some irritation was observed following a three-fold dose administered intramuscularly.


In cattle, no flunixin-related changes or adverse reactions were noted when administered at the one-time (1X) dose for nine days, which is three times the maximum clinical duration. Minimal toxicity was observed at moderately elevated doses (3X and 5X) when flunixin was administered daily for nine days. In some cases, there were occasional findings of blood in the feces and/or urine. Discontinue use if hematuria or fecal blood is observed.

Potential Adverse Reactions

In rare instances, horses may experience local reactions, such as localized swelling, sweating, induration, and stiffness following intramuscular injection, particularly in the neck area. It’s important to note that rare cases of fatal or nonfatal clostridial infections or other infections have been reported in association with intramuscular use of Prevail Flunixin in horses.

Both horses and cattle may experience anaphylactic-like reactions in rare instances, some of which have been fatal. These reactions are primarily reported following intravenous use.


To ensure the efficacy of Prevail Flunixin, it’s crucial to store it between 2° and 30°C (36° and 86°F).

For more information about Prevail Flunixin and its uses, you can visit Katten TrimSalon. Take care of your animals and provide them with the relief they need!