piroxicam
Alti-Piroxicam ◆, Apo-Piroxicam ◆, Feldene, Novo-Pirocam ◆, Nu-Pirox ◆

Available forms
Available by prescription only
Capsules: 10 mg, 20 mg

Indications and dosages
 Osteoarthritis, rheumatoid arthritis. Adults: 20 mg P.O. once daily. If desired, the dose may be divided.
 Juvenile rheumatoid arthritis ◇. Children who weigh 46 to 55 kg (101 to 121 lb): 15 mg P.O. daily.
Children who weigh 31 to 45 kg (68 to 100 lb): 10 mg P.O. daily.
Children who weigh 15 to 30 kg (33 to 67 lb): 5 mg P.O. daily.

Pharmacodynamics
Analgesic, antipyretic, and anti-inflammatory actions: Exact mechanisms unknown. Thought to inhibit prostaglandin synthesis.

Pharmacokinetics
Absorption: Absorbed rapidly from GI tract. Food delays absorption.
Distribution: Highly protein-bound.
Metabolism: Metabolized in liver.
Excretion: Excreted in urine. Long half-life (about 50 hours) allows for once-daily dosing.

Contraindications and precautions
Contraindicated in patients hypersensitive to drug. Use cautiously in elderly patients and in patients with GI disorders, hypertension, conditions predisposing to fluid retention, or history of renal, peptic ulcer, or cardiac disease. Also use cautiously in those with bronchospasm or angioedema precipitated by aspirin or NSAIDs, during pregnancy, or while breast-feeding.

Interactions
Drug-drug. Acetaminophen, gold compounds, other anti-inflammatories: Increases nephrotoxicity. Monitor patient for toxicity.
Anticoagulants, thrombolytics (coumarin derivatives, heparin, other highly protein-bound drugs): May potentiate anticoagulant effects. Monitor PTT, PT, and INR.
Antihypertensives, diuretics: Decreases effectiveness of these drugs; using piroxicam with diuretics may increase risk of nephrotoxicity. Monitor patient.
Anti-inflammatories, corticosteroids, corticotropin, salicylates: Causes GI adverse effects, including ulceration and hemorrhage. Use together cautiously.
Aspirin: Decreases bioavailability of piroxicam. Don’t administer together.
Coumarin derivatives, nifedipine, phenytoin, verapamil: Piroxicam may displace highly protein-bound drugs. Monitor patient for toxicity.
Drugs that inhibit platelet aggregation (such as aspirin, cefamandole, cefoperazone, dextran, dipyridamole, mezlocillin, piperacillin, plicamycin, salicylates, sulfinpyrazone, ticarcillin, valproic acid, other anti-inflammatories): May cause bleeding problems. Monitor patient.
Insulin, oral antidiabetics: Potentiates hypoglycemic effects. Monitor serum glucose level.
Lithium, methotrexate: Decreases renal clearance of these drugs. Monitor plasma levels.
Ritonavir: May increase toxicity of piroxicam. Monitor patient for increased adverse effects if used together. Avoid using together if possible.
Drug-herb. Dong quai, feverfew, garlic, ginger, horse chestnut, red clover: May increase risk of bleeding. Discourage use together.
St. John’s wort, dong quai: Increases risk of photosensitivity. Advise patient to avoid unprotected exposure to sunlight.
Drug-lifestyle. Alcohol use: Increases GI adverse effects, including ulceration and hemorrhage. Discourage alcohol use.
Sun exposure: Causes photosensitivity reaction. Advise patient to take precautions.

Adverse reactions
CNS: headache, drowsiness, dizziness, somnolence, vertigo.
CV: peripheral edema.
EENT: auditory disturbances.
GI: epigastric distress, nausea, occult blood loss, peptic ulceration, severe GI bleeding, diarrhea, constipation, abdominal pain, dyspepsia, flatulence, anorexia, stomatitis.
GU: nephrotoxicity.
Hematologic: prolonged bleeding time, anemia, leukopenia, aplastic anemia, agranulocytosis, eosinophilia, thrombocytopenia.
Skin: pruritus, rash, urticaria, photosensitivity.

Effects on lab test results
• May increase BUN, creatinine, liver enzyme, and potassium levels. May decrease glucose levels.
• May increase PT, PTT, and INR and eosinophil count. May decrease hemoglobin, hematocrit, and WBC, platelet, and granulocyte counts.

Overdose and treatment
To treat piroxicam overdose, empty stomach immediately by inducing emesis with ipecac syrup or by gastric lavage. Administer activated charcoal via nasogastric tube. Provide symptomatic and supportive measures, such as respiratory support and correction of fluid and electrolyte imbalances. Monitor laboratory parameters and vital signs closely.

Special considerations
• Drug is usually administered as a single dose.
• Adverse skin reactions are more common with piroxicam than with other NSAIDs; photosensitivity reactions are the most common.
• Effectiveness isn’t usually seen for at least 2 weeks after therapy begins. Evaluate response to drug as evidenced by reduced symptoms.
• Monitor renal and hepatic function and CBC periodically during therapy.
• Drug hasn’t been proven safe for fetus.
Breast-feeding patients
• Drug may inhibit lactation. Drug appears in breast milk at 1% of maternal serum levels. Avoid use in breast-feeding women.
Pediatric patients
• Safe use of long-term piroxicam in children hasn’t been established.
Geriatric patients
• Patients older than age 60 are more sensitive to drug’s adverse effects. Use cautiously. Because of its effect on renal prostaglandins, drug may cause fluid retention and edema. This may be significant in elderly patients and in those with heart failure.

Patient education
• Advise patient to call before taking OTC or herbal products.
• Advise patient to take after meals to reduce adverse GI effects.
• Caution patient to avoid hazardous activities until CNS effects are known. Instruct patient in safety measures to prevent injury.
• Review adverse effects. Tell patient to report them immediately.
• Encourage patient to comply with recommended medical follow-up.
• Tell patient to avoid aspirin and alcohol.

Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE THREATENING.
◆ Canada only
◇ Unlabeled clinical use