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phenylbutazone

M01AA01

Forms & Strengths

Oral tablets: 100 mg

Adult Dosing

Rheumatoid arthritis and osteoarthritis: 300 to 400 mg daily in divided doses
Gouty arthritis: Initial 400 mg, then 100 mg every 4 hours until acute attack subsides
Maximum daily dose: 400 mg; limit short-term therapy to 1 week

Pediatric Dosing

Safety and efficacy in pediatric patients have not been established; use is generally contraindicated

Indications

Short-term treatment of acute gouty arthritis
Severe rheumatoid arthritis and ankylosing spondylitis unresponsive to safer agents

Mechanism of Action

Nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase (COX-1 and COX-2), reducing prostaglandin synthesis

Contraindications

History of peptic ulcer disease or gastrointestinal bleeding
Significant renal or hepatic dysfunction
History of blood dyscrasias or bone marrow depression
Hypersensitivity to phenylbutazone or other NSAIDs
Cardiovascular disease, hypertension, or edema
Concurrent use with other ulcerogenic drugs or anticoagulants

Adverse Reactions

Agranulocytosis, aplastic anemia, thrombocytopenia
Peptic ulceration, gastrointestinal hemorrhage, perforation
Fluid retention, edema, hypertension, congestive heart failure
Hepatotoxicity, jaundice
Acute renal failure, nephrotic syndrome
Skin rashes, Stevens-Johnson syndrome

Drug Interactions

Anticoagulants (e.g., warfarin): increased bleeding risk due to displacement from plasma proteins and inhibition of metabolism
Oral hypoglycemics (e.g., sulfonylureas): enhanced hypoglycemic effect
Lithium: decreased renal clearance leading to increased toxicity
Antihypertensives and diuretics: reduced antihypertensive efficacy and increased nephrotoxicity
Methotrexate: increased hematologic toxicity due to reduced clearance

Curated Content: Needs Vetting Before Put to Clinical Use