Equipalazone

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Medically reviewed

Marina Burgos

Last updated on 10/01/2026

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Equipalazone

Quick Facts

The active ingredient is Phenylbutazone, which is supplied in multiple forms, including oral powder, oral paste, and solution for injection. It belongs to the Non-steroidal anti-inflammatory drug (NSAID) class, and its general purpose is to manage inflammatory conditions in horses and ponies. Phenylbutazone is an entirely synthetic compound.


What Type of Medicine is Equipalazone (Phenylbutazone)?

Equipalazone is the commercial name for a veterinary medicinal product whose active agent is the synthetic compound Phenylbutazone. This key ingredient is classified as a Non-steroidal anti-inflammatory drug (NSAID) and chemically belongs to the pyrazolone derivative group. This classification defines the medicine's core function: to therapeutically modulate and reduce the body's generalized inflammatory response. Its status as an NSAID means it shares fundamental mechanisms with other anti-inflammatory agents, though it retains a unique chemical profile that has been clinically recognized for its rapid onset of symptomatic relief.


Composition and Available Forms of Equipalazone

The composition of Equipalazone is centered on its single active ingredient, Phenylbutazone. This substance is supplied in various dosage forms to accommodate different initial treatment needs, including a solution for injection for professional, controlled delivery, as well as preparations intended for oral administration, such as an oral powder and an oral paste. This multi-form availability is a differentiating factor, ensuring that the active agent can be introduced effectively either parenterally or via the mouth. The oral preparations are specifically designed for ease of use in the target patient group, often integrated with feed for consumption.


General Purpose and Therapeutic Principles

The general purpose of Equipalazone is to manage the symptoms of inflammation and associated discomfort by providing combined therapeutic effects. Phenylbutazone delivers three fundamental physiological actions: it is strongly anti-inflammatory, acts as an analgesic (relieving pain), and is antipyretic (reducing fever). Phenylbutazone's effects are achieved through its inhibition of prostaglandin synthesis. A typical use scenario involves managing the discomfort, tenderness, and swelling associated with musculoskeletal inflammatory conditions, aiming to stabilize the animal's condition.

Regulatory References

  1. VMD Product Information Database

What side effects are possible with Equipalazone?

Possible Side Effects and Safety Information

Equipalazone (phenylbutazone) is an official non-steroidal anti-inflammatory drug (NSAID) with a documented low therapeutic index, meaning there is a narrow margin between the effective dose and a dose that may cause toxicity. The safety profile is structured around the risk of effects on major organ systems and the potential for severe reactions.

Documented Adverse Reactions by System

Adverse reactions are formally classified by the affected body system, with the most common documented risks centered on the digestive and urinary tracts:

  • Gastrointestinal Disorders: These include the risk of gastric intolerance, ulceration, and bleeding, which can be severe, especially in cases of overdosage.
  • Renal and Urinary Disorders: Documented risks involve kidney disorders and potential renal damage.
  • Blood and Lymphatic System Disorders: The label highlights the risk of blood dyscrasias, a serious adverse reaction.
  • Immune System Disorders: Hypersensitivity (allergic) reactions have been documented.

Frequency Classification

Adverse events are often described in regulatory documents according to how often they occur:

Frequency Category Examples of Documented Reactions
Rare (1 to 10 in 10,000) Gastric intolerance, renal disorder, collapse following intravenous injection.

High-Risk Situations and Restrictions

The official labeling contains specific safety cautions for use in vulnerable situations:

  • Population-Specific Cautions: Additional risks are documented for use in aged, debilitated, or young animals (under 6 weeks), requiring special clinical management. Use in dehydrated, hypovolaemic, or hypotensive animals should be avoided due to the increased risk of toxicity.
  • Pregnancy: The safety of phenylbutazone has not been established in pregnancy and use should be avoided, especially during the first trimester.
  • Long-Term Exposure: For long-term therapy, the response should be monitored at regular intervals by a veterinarian to manage potential risks associated with prolonged use.

This information structures the drug’s risk profile, emphasizing vigilance against gastrointestinal and renal effects, and adherence to specific limitations for high-risk animals.

Overdose and Emergency Response

The official regulatory profile for Equipalazone (Phenylbutazone) overdose describes a risk of serious and life-threatening toxicity across multiple physiological systems. Documented manifestations include severe gastrointestinal injury, such as peptic ulceration, bleeding, and perforation, which may be signaled by the presence of black or tarry stools. Overdose can also lead to potentially fatal blood dyscrasias, including aplastic anemia and agranulocytosis, as well as signs of acute organ failure like jaundice (hepatitis), severe kidney damage, and central nervous system effects such as convulsions and coma.

Regulatory guidance mandates immediate cessation of therapy at the first sign of adverse effects. Urgent medical attention must be sought immediately if specific signs are observed, including fever, unexplained bruising, sore throat, lesions in the mouth, or any change suggestive of a blood disorder or GI bleeding.

Management is generally symptomatic and supportive. In the context of overdose, this includes the institution of appropriate countermeasures and the necessity for close patient monitoring of hematological and organ function. Individuals with pre-existing impaired renal or hepatic function, along with elderly or debilitated patients, are officially identified as groups facing an increased risk of severe toxicity.

Therapeutic Uses of Equipalazone

What Equipalazone Treats: Main Uses and Benefits

The therapeutic application of Equipalazone (Phenylbutazone) is used across domains where additional symptomatic support is needed, primarily focusing on conditions in horses and ponies that involve symptoms related to inflammatory or irritative states. The medication is used to manage symptoms related to physical discomfort arising from conditions such as osteoarthritic changes, chronic arthritis, laminitis, bursitis, and carpitis.


Key Therapeutic Focus

This medicine is applied across conditions presenting with acute or disruptive episodes of pain, stiffness, and lameness that are associated with inflammation. It plays a role in managing symptoms that create noticeable physiological strain, such as localized swelling, heat, tenderness of soft tissues, and systemic fever.

“The primary goal of use is to help ease the overall symptom burden, contributing to easing the overall symptom load during periods when symptoms intensify.”

This supportive relief may assist with maintaining a sense of stability when symptoms are more noticeable and helps patients cope more steadily with difficult symptomatic episodes.

Quick Fact: Supports Management of Pain, Swelling, and Fever

Regulatory References

  1. DailyMed drug label for Phenylbutazone

Eligibility and Restrictions for Use

Eligibility and Contraindications for Equipalazone

The eligibility to use Equipalazone (Phenylbutazone) is strictly defined by official regulatory documents for its licensed target species, horses and ponies.


Eligibility Status Applicable Population or Condition
Absolute Contraindication Animals with severe cardiac, hepatic, or renal disease; those with a history of blood dyscrasia; or a possibility of gastrointestinal ulceration/bleeding; known hypersensitivity to Phenylbutazone.
Use Restricted / Avoid Animals that are dehydrated, hypovolaemic, or hypotensive. Very young animals (under six weeks old) and aged or debilitated animals.
Pregnancy / Lactation Avoided whenever possible as safety in pregnant or lactating mares has not been established by regulatory authorities.
Food Safety Exclusion Use is not authorized for horses intended for human consumption; treated horses are permanently prohibited from the food supply.

Official prescribing information also prohibits the concurrent use of Equipalazone with other non-steroidal anti-inflammatory drugs (NSAIDs). If the medicine is used in very young or aged animals, the label states they may require special clinical management.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Official regulatory documents define specific interaction patterns for Equipalazone (Phenylbutazone) that dictate administration rules and prohibited combinations. The co-administration of Equipalazone with other Non-steroidal Anti-inflammatory Drugs (NSAIDs) is strictly prohibited and requires a mandatory timing separation of at least 24 hours. Similarly, concomitant use with corticosteroids is classified as a contraindicated combination in some regulatory labels due to the heightened risk of gastrointestinal adverse effects.

Pharmacodynamic and Exposure Interactions

Category Documented Interaction Outcome
Pharmacodynamic Aminoglycoside antibiotics should be avoided due to the potential for nephrotoxic effects. Adverse reactions are exacerbated by co-administration with anticoagulants and other non-steroidal anti-phlogistics.
Exposure-Altering Competition for plasma protein binding with highly protein-bound drugs may increase the non-bound, pharmacologically active concentration of the co-administered drug, potentially leading to toxic effects.

Condition-Specific Constraints

The prescribing information establishes that use must be avoided in physiologically compromised animals that are dehydrated, hypovolaemic, or hypotensive. This constraint addresses a documented risk of increased toxicity when the drug is administered under these specific conditions. Furthermore, the administration of the oral powder is linked to food, as binding to substances like bran or oats may affect the rate of absorption.

Mechanism of Action

Equipalazone's mechanism of action centers on its active constituent, phenylbutazone, which functions as a non-selective inhibitor of the cyclooxygenase (COX) enzyme system. This system comprises two primary isoforms: COX-1 and COX-2.

Molecular and Intracellular Pathways

The drug molecule acts as a non-competitive, time-dependent inhibitor of both COX-1 and COX-2, primarily accumulating at sites of altered capillary permeability. In the arachidonic acid cascade, COX enzymes catalyze the conversion of arachidonic acid into unstable intermediates, specifically prostaglandin G2 ( PGG2) and then prostaglandin H2 ( PGH2).

Downstream Cascades and System-Level Consequences

Phenylbutazone's inhibitory interaction blocks the active site of both COX isoforms, arresting the initial oxygenation and subsequent peroxidase steps. This functional blockade results in a significant, concentration-dependent reduction in the intracellular biosynthesis of downstream prostanoids, including prostaglandins, prostacyclin ( PGI2), and thromboxanes ( TXA2). The systemic physiological consequence is a broad modulation of cellular processes mediated by these lipid mediators, including afferent nerve signaling and local vascular and tissue fluid dynamics.

Dosage and Administration Information

How Equipalazone is Used

Equipalazone (Phenylbutazone) is administered according to a specific, short-term protocol. Usage is governed by the form of the medicine and a dosing schedule that transitions from an initial loading phase to a lower maintenance dose.


Administration Routes and Forms

Administration is performed via two primary routes:

  • Oral: Available as oral powder and oral paste forms, which are administered via the mouth. The powder is typically administered by being mixed into a small quantity of the animal's feed to facilitate intake, while the paste is applied directly to the back of the tongue.
  • Intravenous (IV): The solution for injection is for slow intravenous use only and is reserved for professional, controlled settings. The intravenous route is the only permitted parenteral path, and use via other parenteral routes is prohibited.

Official Dosing Protocol

The usage protocol begins with a high initial loading dose which is subsequently reduced to maintain the clinical effect using the lowest quantity of drug possible.

Administration Phase Daily Dose Range (Horse) Frequency Pattern
Initial Dose (Day 1) 4.4 mg/kg of body weight Divided doses (Twice Daily)
Maintenance Dose 2.2 mg/kg to 4.4 mg/kg Once or Twice Daily

Treatment duration is intended to be for the shortest duration possible required to control acute symptoms. Administration should be discontinued if no clinical response is observed within 4 to 5 days. The maintenance dose may be adjusted downwards after the first 24 hours to minimize drug exposure over the short course of treatment.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Equipalazone

Evidence Supporting Musculoskeletal Uses

Research has extensively evaluated Phenylbutazone (Equipalazone) for musculoskeletal disorders and chronic osteoarthritic conditions. Primary research includes Randomized Controlled Trials (RCTs) and controlled lameness models designed to explore short-term symptom changes in horses and ponies. Outcomes research examined included measurements of lameness scores and assessment of physical discomfort. However, uncertainty remains regarding the substance's relationship to the underlying joint disease itself, and findings have been mixed regarding specific markers of cartilage metabolism.


Studies on Localized Inflammatory Conditions

The substance was studied for conditions associated with acute or disruptive episodes, such as laminitis, bursitis, and carpitis. Research explored how symptoms evolved when the drug was used in these settings, monitoring changes in localized heat and swelling. The evidence is limited by the lower number of large-scale, dedicated RCTs for these specific indications compared to general pain studies.


Research on Post-Surgical Support

The research exploring the use of Phenylbutazone in the post-operative setting was studied for managing localized swelling and discomfort. This evidence is largely derived from settings with varying symptom burdens, consisting mainly of clinical monitoring protocols and observational studies. Evidence quality varies across studies because this area often relies on routine clinical data rather than dedicated controlled trials.


Duration of Effect and Long-Term Follow-up

Research has explored the duration over which measured symptom patterns are observed in the studied populations. Follow-up durations in core efficacy trials were typically limited to the short-term. Long-term effects are not fully established by prospective, controlled trials, and there is limited information for long-term outcomes regarding sustained use.


Evidence in Specific Populations and Subgroups

While the main research focused on adult horses, specific studies was observed in foals (younger animals) to assess the drug's physiological behavior. Regulatory documents also note that older or aged animals are a subgroup that was studied for how outcomes were measured. However, data for certain groups remain insufficient, and subgroup findings are uncertain due to modest sample sizes.


Key Limitations and Areas of Uncertainty

The research on Equipalazone has several key limitations. The study structure restricts the design of certain clinical trials. The follow-up durations were limited in many core efficacy studies. Additionally, known uncertainty surrounds the drug's relationship to tissue integrity, where findings were mixed regarding specific biomarkers of cartilage health.

Key Studies & References

  1. Phenylbutazone Monograph (2020) - RMTC
  2. DailyMed Drug Label for Phenylbutazone (Equine Oral Paste) - NIH/NLM
  3. ATCvet Classification: General Principles - WHO Collaborating Centre for Drug Statistics Methodology

Frequently Asked Questions (FAQ)

Common questions about Equipalazone (FAQ)

Q: How quickly should I expect to see an effect after using Equipalazone?

A: Clinical studies and official guidance suggest that a clinical effect may become apparent within the first 24 hours after administration. Regulatory guidance often advises discontinuing the treatment if no clinical response is observed within 4 to 5 days.


Q: What is the typical duration of action for Equipalazone?

A: Pharmacological studies indicate that the anti-inflammatory effects of the active ingredient are commonly monitored over a 24-hour period following a dose. This time frame is often relevant to drug monitoring protocols.


Q: Is it normal to see an improvement for a few days even after stopping Equipalazone?

A: Research indicates that residual pharmacological effects of the active ingredient can persist for 24 hours or longer following the last dose. This suggests that a sustained clinical effect beyond the cessation of treatment is possible.


Q: Why does Equipalazone sometimes cause fluid retention or swelling?

A: Like other Non-steroidal Anti-inflammatory Drugs (NSAIDs), Equipalazone's active ingredient works by inhibiting certain enzymes that can affect the body's fluid and electrolyte balance. Adverse reaction reports include the risk of fluid retention, as this class of drug can influence fluid balance.


Q: What kind of medical conditions prevent the use of Equipalazone?

A: Official product information states that Equipalazone is contraindicated (should not be used) if there is pre-existing severe conditions, including cardiac (heart), hepatic (liver), or renal (kidney) disease. It should also be avoided if there is a history of blood disorders or possible gastrointestinal bleeding/ulceration.


Q: Does Equipalazone interact with commonly used antibiotics?

A: Regulatory warnings specifically highlight a negative interaction with aminoglycoside antibiotics, advising they be avoided due to the potential for increased nephrotoxic (kidney-damaging) effects. Standard product information does not generally list specific interactions with all other classes of antibiotics.


Q: Are there any supplements or vitamins that interact with Equipalazone?

A: Official regulatory documents focus primarily on interactions with other medicines. However, available research has noted that certain substances, such as Vitamin K, may potentially interfere with the drug's effects, although this is not always systematically listed in product information.


Q: What is the importance of blood tests while on long-term Equipalazone therapy?

A: The official labeling indicates the importance of monitoring the patient's response at regular intervals during long-term therapy. This monitoring helps manage potential risks, including serious issues like blood dyscrasias (disorders of the blood components).


Q: What is the difference between Equipalazone powder and the oral paste form?

A: Both are provided for oral use, but studies suggest the absorption rate can differ between forms. The oral paste potentially exhibits a slower absorption profile compared to the powder.


Q: What research is available about the long-term safety of Equipalazone?

A: Official documentation notes that the follow-up periods in core efficacy trials were generally short-term. Therefore, the long-term effects are not fully established by prospective, controlled trials, and sustained long-term use has limited outcome data.


Q: Does Equipalazone affect blood clotting, similar to some other NSAIDs?

A: The active ingredient inhibits a body system that influences platelet function, which plays a role in blood clotting. For this reason, the drug is generally contraindicated for concurrent use with anticoagulant medicines.


Q: Is Equipalazone an antibiotic or a painkiller?

A: Equipalazone is not an antibiotic. It is classified as a Non-steroidal Anti-inflammatory Drug (NSAID). Its function is to reduce inflammation, relieve pain (analgesic), and reduce fever (antipyretic).


Q: Why is Equipalazone powder sometimes given with feed?

A: Official administration instructions recommend mixing the powder into a small quantity of the feed. This is done to facilitate intake and help ensure the medicine is fully consumed by the patient.


Q: Is there a taste or flavor to Equipalazone powder or paste?

A: The active ingredient itself is a chemical compound, but some oral powder formulations contain an added Butter vanilla flavour as a non-active ingredient. This is included to help make the product more palatable.


Q: Does Equipalazone contain sugar or artificial sweeteners?

A: Regulatory product information lists all ingredients, including non-active excipients. While the drug itself is a synthetic chemical, specific formulations may contain various excipients, such as flavouring agents, depending on the manufacturer.


Q: Is it required to stop Equipalazone before certain health exams or procedures?

A: Because of its ability to relieve pain, the drug can potentially mask clinical signs of a condition. Certain regulatory bodies for activities like equestrian sports therefore require a mandatory withdrawal period before official examination or competition.


Q: What is the shelf life of Equipalazone powder once the box is opened?

A: Official storage instructions state that for powder formulations provided in multi-dose boxes, the product's shelf life after first opening the immediate packaging is typically 28 days. Single-dose sachets should generally be used immediately.


Q: What should be done in case of accidental skin contact with Equipalazone powder or paste?

A: Official safety data indicates that if accidental skin contact occurs, the exposed area should be washed thoroughly with soap and water. Any contaminated clothing should also be removed, as advised by safety sheets.


Q: Is Equipalazone considered a 'low therapeutic index' drug, and what does that mean?

A: Yes, Equipalazone is officially documented as having a low therapeutic index. This is a safety term meaning there is only a narrow margin between the dose that provides a therapeutic effect and a dose that may cause signs of toxicity.


Q: How is the active substance in Equipalazone absorbed into the system?

A: The active substance is absorbed through the gastrointestinal tract, but studies show the rate of absorption is slow and variable. This process is influenced by the presence or absence of feed in the digestive tract.


Q: Does the efficacy of Equipalazone change when mixed with different types of feed?

A: Official information indicates that binding to substances in feed, such as bran or oats, may affect the rate of absorption. This change in absorption can influence the time it takes for the drug to reach its peak concentration.


Q: Why is it important not to use Equipalazone in dehydrated subjects?

A: Use must be avoided in compromised animals that are dehydrated, hypovolaemic (low blood volume), or hypotensive (low blood pressure). Regulatory documents link these conditions to a documented risk of increased drug toxicity.


Q: Is it normal to have a reduced appetite after using Equipalazone?

A: Anorexia (reduced appetite) has been documented in official adverse event reports. It is recognized as one of the clinical signs of potential gastrointestinal adverse effects or toxicity associated with the active ingredient.


Q: How does Equipalazone compare to other anti-inflammatory drugs in its class?

A: In some studies, the clinical improvement observed with Equipalazone's active ingredient has been evaluated alongside other NSAIDs in its class for conditions like osteoarthritis.

How should Equipalazone be stored and disposed of?

How to Store and Dispose of Equipalazone

Official regulatory guidelines for Equipalazone (Phenylbutazone) storage and disposal depend on the specific formulation.


Storage Conditions and Stability

The solution for injection requires specific storage: Store in a refrigerator (2 C to 8 C) and protect from light. Both the oral paste and oral powder must not store above 25 C, and the powder must be kept in a dry place. The shelf life after first opening the immediate packaging is 28 days for both the paste and the injection.

Disposal and Safety

All formulations must be kept out of the sight and reach of children. Unused product and waste materials must be disposed of in accordance with national requirements, typically through take-back schemes. The medicine should not be disposed of via wastewater.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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