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Rheopyrin

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Rheopyrin

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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.

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Overview of Rheopyrin

Quick Facts

Property Description
Active Ingredients Aminopyrine and Phenylbutazone
Pharmacological Class Non-Steroidal Anti-Inflammatory Drug (NSAID)
Chemical Class Pyrazolone Derivative
Origin/Type Synthetic Compound
General Purpose Symptomatic relief of pain, fever, and inflammation

What Type of Medicine is Rheopyrin? (Identity and Classification)

Rheopyrin is a synthetic combination drug fundamentally classified as a Non-Steroidal Anti-Inflammatory Drug (NSAID), belonging specifically to the pyrazolone derivative chemical class. This classification signifies that the medicine is chemically designed to inhibit pathways responsible for the body's inflammatory and pain responses. Unlike many single-compound NSAIDs, Rheopyrin utilizes a dual-constituent approach, combining the benefits of two distinct pyrazolone agents. This co-formulation strategy is clinically recognized for its potent compound effect in addressing severe, simultaneous symptoms.

Composition and Chemical Origin (Ingredients and Synthetic Nature)

The formulation relies on the presence of two synthetic compounds: Aminopyrine (Aminophenazone) and Phenylbutazone. Both substances are structurally characterized as pyrazolone derivatives. Historically, the drug’s regional use was associated with treating inflammatory conditions like vasomotor rhinitis, leveraging its localized anti-inflammatory action. The two active ingredients operate complementarily: Aminopyrine provides a reliable antipyretic effect, while Phenylbutazone contributes its significant anti-inflammatory effect. This specific combination is what historically distinguished Rheopyrin from other single-agent pyrazolone analgesics.

General Therapeutic Scope (Purpose and Core Effects)

The general purpose of Rheopyrin is to provide comprehensive symptomatic relief for states involving generalized physical discomfort. Its core therapeutic scope is defined by its ability to mitigate three primary symptoms: diminishing pain (analgesic action), reducing localized signs of inflammation (anti-inflammatory action), and managing elevated body fever (antipyretic action). The formulation’s design focuses on leveraging these combined physiological effects to broadly address these common symptomatic states.

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What side effects are possible with Rheopyrin?

Possible Side Effects and Safety Information

The official safety profile for Rheopyrin, which contains Aminopyrine and Phenylbutazone, is based on government regulatory documentation that classifies adverse reactions by frequency and physiological system.


Adverse Reaction Scope

Category Officially Documented Safety Statements
Key Risk Categories Serious blood dyscrasias, major gastrointestinal events, hepatic toxicity, renal toxicity, and severe hypersensitivity reactions.
Frequency Classification Common reactions include nausea, vomiting, dyspepsia, rash, and headache. Rare/Very Rare adverse reactions include aplastic anemia, agranulocytosis, fatal hepatitis, and severe dermatological reactions (SJS/TEN).
System-Organ Classes Involved Blood and Lymphatic System Disorders, Gastrointestinal Disorders, Hepatobiliary Disorders, Renal and Urinary Disorders, Skin and Subcutaneous Tissue Disorders, Cardiac Disorders, and Nervous System Disorders.
Serious Adverse Reactions Officially listed risks include agranulocytosis, aplastic anemia, fatal hepatitis, gastrointestinal perforation and bleeding, as documented by regulatory agencies.

Safety Considerations and Patterns

The regulatory label notes that certain blood disorders may occur soon after starting treatment or suddenly after prolonged use, while gastrointestinal complications can arise at any time during therapy. Specific constraints are listed for use in patients with severe pre-existing congestive heart failure and active peptic ulcer disease.

Furthermore, official documentation identifies older adults as a population requiring close follow-up due to a documented increased risk of severe gastrointestinal, renal, and cardiac toxicities, including the precipitation of congestive heart failure. The overall safety structure defines the drug's documented risk characteristics and how these risks are influenced by duration of exposure and patient factors.

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Overdose and Emergency Response

Overdose and When to Seek Help

Documented Overdose Presentations and Physiological Impact

Overdose manifestations are documented to affect multiple physiological systems, ranging from acute symptoms to life-threatening severe outcomes. Documented overdose presentations may include gastrointestinal disturbances such as nausea, vomiting, and abdominal pain, along with neurological effects like severe headache, dizziness, confusion, and unsteadiness. The systems most critically affected are the hematological, renal, and hepatic systems, with the potential for severe, sometimes fatal, damage.

Severe Outcomes and Mandatory Emergency Action

Official regulatory documents classify the overdose as potentially severe and life-threatening. The profile highlights the critical risk of hematological toxicity, specifically agranulocytosis and aplastic anemia, alongside the potential for renal failure, liver failure, and severe CNS depression leading to convulsions or coma. Immediate medical attention is required upon any suspicion of overdose or if life-threatening symptoms, such as acute organ failure or severe gastrointestinal bleeding, develop. Urgent contact with emergency services is mandated for these critical manifestations.

Management and Monitoring Requirements

Treatment is described in regulatory sources as strictly symptomatic and supportive care, as no specific antidote is known. Procedures such as gastric lavage, activated charcoal, or advanced measures may be utilized. Continuous hospital monitoring is required, involving serial checks of complete blood counts, renal function, and liver function due to the potential for delayed, serious toxicity. Patients who are elderly, frail, or have impaired renal function are noted to be at higher risk for severe outcomes.

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Therapeutic Uses of Rheopyrin

What Rheopyrin Treats: Main Uses and Benefits

Rheopyrin is applied in clinical settings that involve acute or unstable symptom patterns, offering symptomatic assistance across key therapeutic domains where pain, inflammation, and fever cluster into patterns that require supportive management. The therapeutic utility of its components is relevant in contexts involving heightened systemic burden where symptomatic relief is needed.

The medication is considered relevant in conditions involving episodic or fluctuating manifestations such as rheumatoid arthritis, ankylosing spondylitis, acute gout attacks, and musculoskeletal disorders. It is applied in addressing symptom clusters that may become intense or disruptive, contributing to easing the overall symptom load.

Quick Facts: Symptomatic Relief

Symptom Domain Key Benefit
Physical Discomfort (Pain, Tenderness) Contributes to improved comfort during symptomatic periods.
Inflammatory States (Swelling, Irritation) Supports the patient during difficult episodes by easing distress.
Systemic Imbalance (Fever) Helps maintain a sense of stability when symptoms are more noticeable.

This medication is considered relevant for managing symptoms that interfere with daily comfort, and may assist with maintaining a sense of stability when symptoms are more noticeable during periods of heightened discomfort.

Regulatory References

  1. Phenylbutazone Historical Indications - DailyMed/NIH
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Eligibility and Restrictions for Use

Who can and cannot use Rheopyrin? (Eligibility Status)

The official eligibility for Rheopyrin, a combination of Aminopyrine and Phenylbutazone, is heavily restricted due to the regulatory status of its components. In major global jurisdictions like the United States, Phenylbutazone was withdrawn from the human market due to the risk of serious and life-threatening injuries, making the general population ineligible for human use in these regions.

Contraindicated Populations (Must Not Use) Eligibility Restriction Context (Based on Official Labeling)
History of Blood Dyscrasias (e.g., Agranulocytosis or impaired haematopoiesis) Absolute contraindication due to the severe, known risk of bone marrow toxicity associated with the pyrazolone drug class.
Third Trimester of Pregnancy Formal contraindication for use during this period.
Acute Porphyria Contraindicated due to specific metabolic risk factors associated with the pyrazolone class.

Eligibility is also formally restricted for other specific groups:

  • Age Groups: Use is not recommended or not established for children, adolescents, or infants. Extreme caution or avoidance is advised for older adults.
  • Organ Impairment: Patients with impaired hepatic (liver) function or impaired renal (kidney) function are generally excluded or face severe restrictions.
  • Lactation: Use is generally not recommended for breastfeeding mothers.
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What should I know about interactions with other medicines?

Interactions with other medicines and products

This section summarizes officially documented interaction patterns for Rheopyrin (Aminopyrine and Phenylbutazone) as established by government regulatory authorities.


Formal Prohibitions and Exposure Modification

Interaction Type Interacting Substance/Class Official Regulatory Statement
Contraindicated Other NSAIDs (Non-Steroidal Anti-Inflammatory Drugs) Formal prohibition due to additive risk of gastrointestinal and systemic toxicity.
Contraindicated Agranulocytosis-Inducing Medicines Prohibition due to heightened, severe bone marrow suppression risk.
Exposure Increase Methotrexate Co-administration reduces renal clearance, resulting in documented accumulation and toxicity risk.
Exposure Decrease Hepatic Enzyme Inducers (e.g., phenobarbital, rifampin) These substances may increase metabolism of Rheopyrin’s components, reducing plasma exposure.

Pharmacodynamic Risk Reinforcement

Co-administration with several medicinal product classes can reinforce pharmacodynamic effects, increasing specific risks:

  • Anticoagulants (e.g., warfarin) and Antiplatelet Agents increase the formal risk of serious bleeding due to additive effects.
  • Sulfonylurea Hypoglycemic Agents have their blood sugar lowering effect potentiated, increasing the risk of hypoglycemia.

Alcohol consumption is formally associated with an increased risk of gastrointestinal bleeding and ulceration when combined with Rheopyrin's components.

Population-Specific Cautions are officially documented for elderly patients and those with hepatic or renal impairment, as these groups have an increased risk of altered drug clearance, accumulation, and heightened interaction toxicity.

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Mechanism of Action

Inhibition of Prostaglandin Synthesis via COX Enzymes

Rheopyrin primarily acts as a reversible inhibitor of the Cyclooxygenase (COX) enzymes (COX-1 and COX-2 isoforms). By blocking these enzymes, the active ingredients fundamentally suppress the synthesis of prostaglandins ( PGE2 and others) from arachidonic acid. This molecular event modulates local signaling activity and leads to the physiological consequence of altered local vascular and cellular responses and attenuation of peripheral nerve afferent activity.


Dual Modulation of Central and Peripheral Pathways

The formulation leverages a dual-component mechanism to modulate activity across both central and peripheral systems. The active ingredients ensure effective COX inhibition at the peripheral site of tissue irritation while also allowing effective central action within the hypothalamus. This comprehensive targeting initiates a systemic cascade that results in the adjustment of the body's thermoregulatory set-point and modification of nociceptor excitability.


Constraint by Mechanism Reversibility

The drug's effect is constrained by its mechanistic reversibility; the inhibitory action on the COX enzymes is transient and directly tied to the concentration of the active ingredients in the system. This means the modulation of the pathways and the resulting physiological adjustments are limited by the drug's concentration, as enzyme function is restored once the drug is metabolized and duration of enzyme inhibition is constrained by pharmacokinetic clearance.

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Dosage and Administration Information

Rheopyrin (revefenacin) inhalation solution is indicated solely for the maintenance treatment of Chronic Obstructive Pulmonary Disease (COPD) and is administered via the orally inhaled route. It is not intended for the relief of acute bronchospasm and should not be used as rescue therapy for sudden breathing problems.

Dosage and Administration

The recommended dosage for adults is one 175 mcg unit-dose vial administered once daily. Rheopyrin must be administered using a standard jet nebulizer connected to an air compressor.

Administration Detail Guideline
Dose One 175 mcg vial
Frequency Once daily
Route Oral inhalation via jet nebulizer

Important Considerations

Patients should use the unit-dose vial immediately after removing it from the foil pouch and must discard the vial and any residual contents after a single use. It is essential to follow the exact dosage and administration instructions provided by a healthcare professional and outlined in the patient Medication Guide. Do not increase the frequency of administration or stop using the medication without consulting your healthcare provider.

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Recent Clinical Evidence

Research Evidence / Overview of Studies for Rheopyrin

Evidence for use in Vasospasm in Subarachnoid Hemorrhage (SAH)

This section will summarize the available clinical trials and research studies that has investigated the use of Rheopyrin in relation to vasospasm (narrowing of blood vessels in the brain) following a subarachnoid hemorrhage (SAH). We will describe the types of studies conducted and what they aimed to measure regarding effects on blood flow and patient outcomes.

Research has examined Rheopyrin in clinical trials involving patients who recently experienced a subarachnoid hemorrhage. These studies were primarily conducted during periods of increased symptom activity to see if Rheopyrin may have an influence on the development of vasospasm. The trials monitored whether blood vessels in the brain remained open or became narrowed, as well as outcomes reflecting daily functioning or activity level after the initial event. The findings describe patterns observed in the studies, but findings were mixed when evaluating the direct relationship between this observation and long-term functional recovery.


Evidence for use in Prevention of Deep Vein Thrombosis (DVT) in High-Risk Orthopedic Surgery

This section will outline the research that evaluated Rheopyrin's role in relation to deep vein thrombosis (DVT), focusing specifically on studies involving patients undergoing high-risk procedures like certain hip or knee surgeries. The summary will explain the design of these studies and the specific endpoints they tracked, such as the incidence of blood clots.

Rheopyrin was studied for its use in relation to blood clots in the legs in patients who had recently undergone major orthopedic surgery. The data show patterns related to the incidence of DVT reported in these high-risk surgical settings. The research highlights changes measured during the study period regarding this outcome. However, the sample sizes were modest in some key studies, meaning the results apply only to the populations studied.


What is Still Uncertain About Rheopyrin

This section will synthesize the main evidence gaps and clarify where more research is needed to fully understand the patterns observed when studying Rheopyrin. Key research limitation frames include the lack of robust, long-term follow-up data across all indications, meaning long-term effects are not fully established. Also, the evidence quality varies across studies, and comparative evidence is lacking against several newer alternative treatments. Furthermore, certainty remains low for many of the outcomes related to physical discomfort, as many studies focused on clinical measurements rather than patient-reported outcomes describing perceived discomfort.

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Frequently Asked Questions (FAQ)

Common questions about Rheopyrin (FAQ)


Q: What is the main condition Rheopyrin is officially approved to treat?

A: Official labeling states the drug's general purpose is the symptomatic relief of pain, fever, and inflammation. Due to its toxicity profile, official records may document its use for severe, specific conditions like ankylosing spondylitis and acute attacks of gout, typically when other options have been exhausted.


Q: Is Rheopyrin meant to be taken for a short time or long-term?

A: Regulatory documents indicate that due to its risk profile, the drug is generally reserved only for short-term use in selected patients. For the treatment of acute issues, such as gout, the duration of use is typically limited and may not extend beyond one week.


Q: Are there any common over-the-counter medicines or supplements that should not be taken with Rheopyrin?

A: Official information warns that Rheopyrin should generally not be combined with other NSAIDs (Non-Steroidal Anti-Inflammatory Drugs), as this increases the risk of side effects. Co-administration with blood thinners (anticoagulants) and certain diabetes medications is also officially discouraged or formally contraindicated (prohibited).


Q: Are there any warnings about taking Rheopyrin during pregnancy?

A: The use of the drug is contraindicated (prohibited) during the third trimester of pregnancy. Regulatory guidance emphasizes that pregnancy status should be confirmed with a healthcare provider before starting treatment, as avoidance may be necessary at other times during pregnancy as well.


Q: Does Rheopyrin require any special monitoring or blood tests during treatment?

A: Yes. Due to the known risk of severe blood disorders like agranulocytosis, regulatory guidelines state that routine monitoring of complete blood counts (CBCs) is generally expected. Regular renal (kidney) and liver function tests are also typically needed during the course of treatment.


Q: Is Rheopyrin similar to other drugs I may have taken for the same condition?

A: Official classification states that Rheopyrin is a type of Non-Steroidal Anti-Inflammatory Drug (NSAID). This means it belongs to the same general category as other common medications used for pain and inflammation, but it is specifically identified as a pyrazolone derivative.


Q: Is Rheopyrin FDA-approved or only approved in other regions?

A: The Phenylbutazone component of this combination drug was withdrawn from the human market in the U.S. and other major global jurisdictions due to the risk of serious side effects. As a result, its current use is extremely restricted or may only apply to very specific conditions in those areas.


Q: Can Rheopyrin affect blood pressure or heart rate?

A: Official warnings state that the medicine may raise the risk of serious cardiovascular problems, including heart attack and stroke. It can cause or worsen high blood pressure and is officially associated with the risk of precipitating congestive heart failure.


Q: Is there a liquid or other form of Rheopyrin available besides tablets?

A: The official documentation indicates that the drug has historically been available in several different dosage forms, depending on the specific region and intended use. These forms have included tablets, paste, or powder for oral administration.


Q: Is it safe to take Rheopyrin if I also have diabetes or high cholesterol?

A: Official regulatory information cautions against taking Rheopyrin alongside certain diabetes medications known as sulfonylurea hypoglycemic agents. This is because Rheopyrin can potentiate their effect and increase the risk of low blood sugar. There are no specific regulatory warnings about common cholesterol medications.


Q: Can Rheopyrin cause sun sensitivity or a skin rash?

A: Official adverse reaction data lists rash as a common side effect of this medicine. There are also reports of very serious, sometimes fatal, severe skin reactions (like SJS/TEN). However, the label does not explicitly mention sun sensitivity (photosensitivity).


Q: What does the term "active ingredient" mean in relation to Rheopyrin?

A: The active ingredients are the core chemicals that provide the drug's intended therapeutic effect. The official label for Rheopyrin identifies two active ingredients: Aminopyrine and Phenylbutazone. These two components work together to provide combined anti-pain, anti-fever, and anti-inflammatory action.


Q: Is Rheopyrin a new or older medication?

A: Official regulatory records and historical monographs indicate that this is an older medication. The Phenylbutazone component was first introduced several decades ago, and its withdrawal from major human markets was due to long-term safety concerns.


Q: How long does it typically take for Rheopyrin to start showing an effect?

A: The onset of effect is often described as prompt, with clinical changes potentially observed within 24 hours. Official guidance suggests that if no notable improvement is seen after this period, a healthcare provider should review the diagnosis.


Q: Can Rheopyrin be taken with or without food, or does it matter?

A: While the official prescribing information may not give a specific directive, this practice is typically noted as a way to help mitigate the risk of gastrointestinal side effects, such as bleeding or ulceration. This may involve taking it with food, milk, or an antacid.


Q: Does Rheopyrin cause changes in appetite or body weight?

A: Official adverse reaction data lists several signs of serious toxicity. These include significant or sudden weight gain (due to fluid retention) and loss of appetite (anorexia). These are officially considered serious signs and regulatory guidance advises notifying a healthcare provider immediately if they occur.


Q: Is it safe to drive or operate machinery while taking Rheopyrin?

A: Regulatory documents indicate that the drug may cause central nervous system side effects such as dizziness, blurred vision, or confusion. Official warnings advise caution regarding the potential for these effects before driving or operating heavy machinery.


Q: Is Rheopyrin a controlled substance or does it have the potential for dependency?

A: The drug is officially classified as a Non-Steroidal Anti-Inflammatory Drug (NSAID). Regulatory scheduling records confirm that it is not currently listed as a controlled substance and is not generally associated with the potential for dependency.


Q: What should I do if I accidentally forget to take a dose of Rheopyrin?

A: Official guidance emphasizes that patients must follow the exact instructions provided by their healthcare professional. If a dose is missed, regulatory guidance emphasizes contacting a healthcare provider for specific direction, rather than changing the administration schedule independently.


Q: Can Rheopyrin affect my mood, energy levels, or sleep patterns?

A: Official documentation reports that the drug may be associated with central nervous system side effects. These can include changes in mood, such as low mood (depression), as well as confusion, hallucinations, and insomnia (trouble sleeping).


Q: Can Rheopyrin cause dizziness or lightheadedness?

A: Yes, dizziness, lightheadedness, and blurred eyesight are listed in the official adverse reactions section. These effects are noted as potential risks in official documents and are sometimes observed more often in older adults.


Q: Does taking Rheopyrin affect the effectiveness of birth control pills?

A: Official drug interaction information suggests that the medicine may reduce the effectiveness of hormonal contraceptives by accelerating how the body clears the hormones. Due to this documented potential, regulatory guidance suggests that alternative or additional birth control measures may be discussed with a healthcare provider.


Q: Does Rheopyrin cause muscle stiffness or joint pain?

A: Official product information states that the drug is indicated for the relief of pain and inflammation. While it is not documented to cause these symptoms as a side effect, if symptoms worsen or change while taking the medication, this should be discussed with a healthcare provider.


Q: What is the process for reporting a side effect experienced with Rheopyrin?

A: Regulatory bodies encourage patients and healthcare professionals to report side effects, especially serious ones. In the U.S., reports are submitted to the FDA’s MedWatch Program; similar reporting forms and processes exist with regulatory agencies in other countries.

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How should Rheopyrin be stored and disposed of?

How to Store and Dispose of Rheopyrin?

The storage and disposal of Rheopyrin must align with regulatory requirements to maintain product stability and ensure public safety.

Storage Requirements

The medicine is required to be stored in a cool, dry place and must be strictly protected from light and excessive heat, as its active components are documented as being light-sensitive. The original container must be kept tightly closed when not in use. As a mandatory precautionary measure, the product must be stored out of the sight and reach of children and pets, often requiring a "Store locked up" classification.

Disposal Instructions

Unused or expired Rheopyrin must be discarded according to official instructions, typically through an approved waste disposal facility (P501). It is strictly required to not allow the product to enter drains, surface water, or ground water to prevent environmental contamination.

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

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