Home Drug Guide Phenylbutazone

Drug Guide

Generic Name

Phenylbutazone

Brand Names Butazolidin, Azolid

Classification

Therapeutic: Anti-inflammatory, analgesic, antipyretic

Pharmacological: Nonsteroidal anti-inflammatory drug (NSAID)

FDA Approved Indications

Not approved for human use in the United States; historically used for acute gout and rheumatic conditions in some countries

Mechanism of Action

Phenylbutazone works by inhibiting cyclooxygenase (COX-1 and COX-2), leading to decreased formation of prostaglandins, which are mediators of inflammation, pain, and fever.

Dosage and Administration

Adult: Typically 300-600 mg orally per day in divided doses, as prescribed by a healthcare professional.

Pediatric: Use is generally not recommended due to toxicity concerns.

Geriatric: Cautious use recommended; start at lower doses due to increased risk of adverse effects.

Renal Impairment: Dose adjustments may be necessary; use with caution.

Hepatic Impairment: Use with caution; monitor liver function.

Pharmacokinetics

Absorption: Well absorbed orally.

Distribution: Widely distributed in body tissues; crosses the placenta.

Metabolism: Metabolized primarily in the liver.

Excretion: Excreted mainly via the kidneys.

Half Life: Approximately 3-6 hours.

Contraindications

Hypersensitivity to phenylbutazone or other NSAIDs
History of blood dyscrasias
Active gastrointestinal ulcers or bleeding
Severe renal or hepatic impairment

Precautions

Use with caution in patients with cardiovascular disease, bleeding disorders, or asthma; risk of serious adverse effects, including blood dyscrasias and aplastic anemia.

Adverse Reactions - Common

Gastrointestinal upset (nausea, gastric pain) (Common)
Dizziness, headache (Common)

Adverse Reactions - Serious

Aplastic anemia (Rare)
Blood dyscrasias, including agranulocytosis and thrombocytopenia (Rare)
Hypersensitivity reactions, bronchospasm (Rare)
Hepatotoxicity (Rare)
Renal failure (Rare)

Drug-Drug Interactions

Aspirin, other NSAIDs, anticoagulants, corticosteroids (increased bleeding risk)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor CBC, liver and renal function tests regularly; watch for signs of bleeding or hypersensitivity.

Diagnoses:

Risk for bleeding
Impaired tissue perfusion related to adverse drug effects

Implementation: Use the lowest effective dose for the shortest duration; observe for adverse effects.

Evaluation: Assess pain relief, monitor for adverse reactions, and evaluate organ function periodically.

Patient/Family Teaching

Report any signs of unusual bleeding, bruising, sore throat, fever, jaundice, or rash.
Inform about potential side effects and the importance of regular monitoring.
Advise against use of alcohol or other NSAIDs concurrently.

Special Considerations

Black Box Warnings:

Serious adverse blood dyscrasias (aplastic anemia, agranulocytosis, thrombocytopenia) can occur; use only when benefits outweigh risks.

Genetic Factors: None well established.

Lab Test Interference: May affect liver function tests, blood counts.

Overdose Management

Signs/Symptoms: Severe gastrointestinal bleeding, blood dyscrasias, renal failure, hypotension.

Treatment: Supportive care; activated charcoal if recent ingestion; hemodialysis in severe cases; manage symptoms and provide supportive care.

Storage and Handling

Storage: Store at room temperature, away from moisture and light.

Stability: Stable under proper storage conditions.