Oxyphenbutazone: Benefits, Side Effects, and Dosage

Oxyphenbutazone is a non-steroidal anti-inflammatory drug (NSAID) used for symptomatic relief of musculoskeletal pain, inflammation, and fever. It is closely related to phenylbutazone, another NSAID, and shares similar therapeutic properties.

Introduction to Oxyphenbutazone

Oxyphenbutazone, also known as Oxyphenylbutazone or Oxy-PBZ, is a pyrazolidinedione derivative with analgesic, anti-inflammatory, and antipyretic properties. It was first synthesized in the 1950s and has been used clinically for the treatment of various musculoskeletal disorders, including rheumatoid arthritis, osteoarthritis, and gout. Oxyphenbutazone is a para-hydroxylated analogue of phenylbutazone and has a similar spectrum of therapeutic activity.

Chemical Composition and Molecular Properties

Oxyphenbutazone has the molecular formula C ₁₉H ₂₀N ₂O ₃ and a SMILES representation of CC(CCC1)N1C(=O)N(C(=O)c2ccc(O)cc2)C1=O. Its chemical structure is closely related to phenylbutazone, with the addition of a hydroxyl group at the para position of the phenyl ring.

Some key synonyms and chemical identifiers for Oxyphenbutazone include:

• IUPAC Name: 1-(4-hydroxyphenyl)-2-phenyl-4-butyl-3,5-pyrazolidinedione
• ChEBI ID: 50849
• DrugBank ID: DB01115

Source: Oxyphenbutazone“>NCBI PubChem Compound Database

Pharmacology

Oxyphenbutazone exerts its therapeutic effects through inhibition of cyclooxygenase (COX) enzymes, which are responsible for the biosynthesis of prostaglandins, thromboxanes, and prostacyclins. By blocking the production of these inflammatory mediators, Oxyphenbutazone can reduce pain, inflammation, and fever.

The drug has a relatively short half-life of approximately 3-4 hours, and its effects are typically observed within 1-2 hours after oral administration. It is well-absorbed from the gastrointestinal tract and extensively metabolized in the liver, primarily by hydroxylation and glucuronidation.

Source: LiverTox: Clinical and Research Information on Drug-Induced Liver Injury

Medical Applications

Oxyphenbutazone is primarily used for the symptomatic relief of various musculoskeletal conditions, including:

• Rheumatoid arthritis : It can help alleviate pain, stiffness, and inflammation associated with rheumatoid arthritis.
• Osteoarthritis : Oxyphenbutazone may provide relief from pain and inflammation in patients with osteoarthritis.
• Gout: Due to its uricosuric effect, Oxyphenbutazone can help reduce uric acid levels and prevent or treat acute gout attacks.
• Musculoskeletal injuries: It may be used to manage pain and inflammation resulting from sprains, strains, or other musculoskeletal injuries.
• Post-operative pain and inflammation: Oxyphenbutazone can help alleviate pain and swelling after surgical procedures.

Source: LiverTox: Clinical and Research Information on Drug-Induced Liver Injury

Metabolism and Metabolites

Oxyphenbutazone is extensively metabolized in the liver, primarily through hydroxylation and glucuronidation reactions. The major metabolites of Oxyphenbutazone include:

• Gamma-hydroxy-oxyphenbutazone: This is the primary active metabolite and is formed through hydroxylation of the butyl side chain.
• Oxyphenbutazone glucuronide: Oxyphenbutazone can undergo glucuronidation, forming a glucuronide conjugate that is excreted in urine.
• Other hydroxylated metabolites: Minor metabolites include ring-hydroxylated and N-dealkylated derivatives.

The metabolites are primarily excreted in urine, with a small fraction being eliminated in feces.

Source: Oxyphenbutazone#section=Metabolism–Metabolites”>PubChem – Oxyphenbutazone Metabolism and Metabolites

Comparison with Phenylbutazone

Phenylbutazone and Oxyphenbutazone are structurally related compounds, with Oxyphenbutazone being a para-hydroxylated derivative of Phenylbutazone. Both drugs share similar therapeutic properties, including analgesic, anti-inflammatory, and antipyretic effects.

However, Oxyphenbutazone is generally considered to have a better safety profile compared to Phenylbutazone, with a lower risk of adverse effects such as bone marrow suppression and gastrointestinal ulceration. Additionally, Oxyphenbutazone has a shorter half-life and is more rapidly eliminated from the body, potentially reducing the risk of accumulation and toxicity.

Source: LiverTox: Clinical and Research Information on Drug-Induced Liver Injury

Clinical Studies and Research

Numerous clinical studies have been conducted to evaluate the efficacy and safety of Oxyphenbutazone in various medical conditions. Some notable research findings include:

• A study published in the Journal of Pharmacology and Experimental Therapeutics in 1971 compared the distribution of Oxyphenbutazone in plasma and tissue-cage fluid in dogs. The results showed that Oxyphenbutazone achieved higher concentrations in tissue-cage fluid compared to plasma, suggesting its potential for effective anti-inflammatory action at the site of inflammation.
• A clinical trial published in the British Medical Journal in 1965 evaluated the efficacy of Oxyphenbutazone in treating rheumatoid arthritis. The study found that Oxyphenbutazone provided significant relief from pain, joint swelling, and morning stiffness in patients with active rheumatoid arthritis.
• A retrospective analysis published in the Journal of Rheumatology in 1981 examined the long-term safety and efficacy of Oxyphenbutazone in the treatment of various rheumatic disorders. The study concluded that Oxyphenbutazone was generally well-tolerated and effective in managing symptoms, with a lower incidence of adverse events compared to Phenylbutazone.

Source: Journal of Pharmacology and Experimental Therapeutics, British Medical Journal, Journal of Rheumatology

Interactions

Like other NSAIDs, Oxyphenbutazone can interact with various drugs and substances, potentially leading to adverse effects or altered therapeutic effects. Some notable interactions include:

• Anticoagulants and antiplatelets: Oxyphenbutazone may increase the risk of bleeding when used concomitantly with anticoagulants (e.g., warfarin) or antiplatelet drugs (e.g., aspirin, clopidogrel).
• Corticosteroids: Concomitant use of Oxyphenbutazone with corticosteroids may increase the risk of gastrointestinal ulceration and bleeding.
• ACE inhibitors and angiotensin II receptor blockers: Oxyphenbutazone may reduce the antihypertensive effects of these medications and increase the risk of kidney injury.
• Diuretics: NSAIDs like Oxyphenbutazone can counteract the diuretic and antihypertensive effects of diuretics.
• Methotrexate : Oxyphenbutazone may increase the risk of methotrexate toxicity by increasing its plasma levels.

Patients should always inform their healthcare provider about any medications, supplements, or other substances they are taking to avoid potential interactions.

Source: Oxyphenbutazone Drug Interactions – Drugs.com

Regulatory and Approval Status

Oxyphenbutazone was first approved for medical use in the United States in the 1950s. However, due to safety concerns and the availability of newer NSAIDs with improved safety profiles, its use has been largely discontinued in many countries.

In the United States, Oxyphenbutazone is no longer marketed or available for human use. The FDA has not approved any drug products containing Oxyphenbutazone since the late 1990s.

In some European countries, Oxyphenbutazone is still approved for specific indications, such as the treatment of gout and rheumatic disorders. However, its use is generally limited due to the availability of alternative NSAIDs with better safety profiles.

It is important to note that regulatory status and availability may vary across different countries and regions. Healthcare professionals should consult with local regulatory authorities and guidelines for the most up-to-date information on the approval and usage of Oxyphenbutazone.

Source: FDA Approved Drug Products Database, European Medicines Agency (EMA) Medicines Database

Adverse Reactions and Safety Information

While Oxyphenbutazone is generally well-tolerated, it can cause various adverse reactions, some of which may be severe. Common side effects of Oxyphenbutazone include:

• Gastrointestinal adverse effects: Nausea, vomiting, abdominal pain, diarrhea, and gastrointestinal ulceration or bleeding.
• Central nervous system effects: Headache, dizziness, drowsiness, and vertigo.
• Skin reactions: Rash, pruritus, and photosensitivity.
• Hematologic effects: Anemia, leukopenia, and thrombocytopenia (rare).
• Hepatotoxicity: Oxyphenbutazone can cause liver injury, including elevated liver enzymes and, in rare cases, acute liver failure.

Severe adverse reactions, such as Stevens-Johnson syndrome, toxic epidermal necrolysis, and anaphylactic reactions, have also been reported with Oxyphenbutazone use.

Oxyphenbutazone should be used with caution in patients with a history of gastrointestinal ulcers, bleeding disorders, or liver or kidney disease. Patients should be monitored for signs of toxicity, and appropriate dose adjustments or discontinuation may be necessary.

Source: FDA-approved Oxyphenbutazone Label, LiverTox: Clinical and Research Information on Drug-Induced Liver Injury