Piroxicam

From Anvita Health Wiki

Contents 1 Introduction 2 Indications 3 Dosage 4 Pharmacokinetics 5 Monitor 6 Adverse-effects 7 Drug-interactions 8 Laboratory 9 Mechanism-of-action 10 More General Terms 11 Additional Terms 12 Internet Database 13 References

Introduction

• Tradename: Feldene.

Indications

• temporary relief of minor aches, pains, fever & inflammation
• symptomatic treatment of acute & chronic rheumatoid arthritis
• osteoarthritis
• ankylosing spondylitis

Dosage

• 20 mg PO QD
• do not assess effect of therapy for 2 weeks
• use with caution or reduced doses in the elderly

• Tabs: 10, 20 mg.

Pharmacokinetics

• food delays absorption [5]
• metabolized in the liver by cyt P450 2C9
• onset of action is several hours
• duration of action is 24 hours
• elimination 1/2life is 48 hours
• 5% of drug is excreted unchanged in the urine
  

• elimination via liver
• 1/2life = 14-158 hours
• protein binding = >99 %
• elimination by hemodialysis = -
• elimination by peritoneal dialysis = -

Monitor

• liver function tests periodically [6]
  
• monitor with non steroidal anti-inflammatory agents (NSIADs)

Adverse-effects

• common (> 10%)

• rash, dizziness, abdominal cramps, heartburn, indigestion, nausea

• less common (1-10%)

• itching, tinnitus, fluid retention, headache, nervousness, vomiting

• uncommon (< 1%)

• congestive heart failure, hypertension, arrhythmias, epistaxis, confusion, hallucinations, aseptic meningitis, depression, peripheral neuropathy, urticaria, erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis, gastritis, GI ulceration, cystitis, agranulocytosis, anemia, hemolytic anemia, bone marrow depression, leukopenia, thrombocytopenia, hepatitis, angioedema, allergic rhinitis, toxic amblyopia, blurred vision, conjunctivitis, dry eyes, decreased hearing, polyuria, shortness of breath, polydypsia, tachycardia, hot flashes, drowsiness, insomnia, acute renal failure

• other

• GI effects & bleeding may be more prominent with piroxicam than with other NSAIDs
• high incidence of phototoxic skin eruptions
• worsening of renal insufficiency
  
• drug adverse effects of NSAIDs

Drug-interactions

• corticosteroids

• increase clearance of salicylates
• increased nephrotoxicity
• increased GI toxicity

• decreased anti-hypertensive effects of ACE inhibitors
• coumadin: prolonged bleeding time
• piroxicam decreases clearance & increases toxicity of:

• methotrexate
• Li+
• digoxin

• any drug which inhibits cyt P450 2C9 can increase piroxicam levels
• any drug which induces cyt P450 2C9 can diminish piroxicam levels
  
• drug interaction(s) of lithium carbonate with NSAIDs
• drug interaction(s) of NSAIDs with SSRIs
• drug interaction(s) of aspirin with NSAIDs
• drug interaction(s) of NSAIDs with beta blockers
• drug interaction(s) of NSAIDs with ARBs
• drug interaction(s) of NSAIDs with ACE inhibitors
• drug interaction(s) of NSAIDs, diuretics & angiotensin II receptor antagonists
• drug interaction(s) of NSAIDs, diuretics & ACE inhibitors
• drug interaction(s) of NSAIDs & loop diuretics
• drug interaction(s) of NSAIDs & aspirin

Laboratory

• specimen:

• serum, plasma, urine
• stable for 14 days at -20 degrees C

• methods: HPLC

Mechanism-of-action

• oxicam class NSAID
• analgesic, antipyretic, anti-inflammatory
• non-selective cyclooxygenase inhibitor

More General Terms

• non-steroidal anti-inflammatory agent (NSAID)
• peroxisome proliferator

Additional Terms

• cytochrome P450 2C9; cytochrome P450 BP-1; cytochrome P450 MP-4; S-mephenytoin-4-hydroxylase; limonene 6-monooxygenase; limonene 7-monooxygenase (CYP2C9, CYP2C10)

Internet Database

PubChem: 4856
PubChem: 5280452
PubChem: 5312135

References

1. The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
2. Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
3. Kaiser Permanente Northern California Regional Drug Formulary, 1998
4. Clinical Guide to Laboratory Tests, 3rd ed. Teitz ed., W.B. Saunders, 1995
5. Harrison's Principles of Internal Medicine, 14th ed. Fauci et al (eds), McGraw-Hill Inc. NY, 1998, pg 470
6. Prescriber's Letter 17(7): 2010 Recommended Lab Monitoring for Common Medications Liver Function Test Scheduling Detail-Document#: [1] (subscription needed) [2]

piroxicam (Feldene)