PIROXICAM (FELDENE)
INDICATIONS
Piroxicam is a non-selective prostaglandin synthesis inhibitor in peripheral tissues with anti-inflammatory, antipyretic (anti-fever), and analgesic properties. Without respect to the cause of the inflammation, piroxicam reduces pain, fever, erythema(redness), tissue proliferation, and edema.
Piroxicam is indicated for the acute and long-term treatment of the management of osteoarthritis and rheumatoid arthritis in the adult patient (18 years of age and older). It is not indicated in pregnant or lactating females due to the risk of cardiovascular damage to the fetus or newborn. It should be prescribed with caution in patients with a history of hypersensitivity to aspirin or any of the non-steroidal anti-inflammatory medications, have a history of asthma, nasal polyps, bronchospasm, or reactive angioedema. The combination of aspirin and piroxicam is not recommended as plasma reduction of the medications is exhibited and may increase spontaneous bleeding.
The drug is well absorbed after oral administration and within 3-5 hours reaches peak plasma concentration with a mean half-life of 5 hours, ranging from 30-86 pending upon individual patient biopharmaceutical parameters( age, GI absorption/motility), thus making once day dosing a benefit of the drug. The drug undergoes hepatic enzyme metabolism and a 2-1 ratio of urine to feces excretion.
SIDE EFFECTS
Side effects of Piroxicam are similar to those of the other NSAIDs and include the gastrointestinal tract, renal(kidney), hepatic(liver)systems, dermatological, central nervous system, and cardiovascular.
The adverse effects of bleeding throughout the gastrointestinal tract, perforation, ulceration, dyspepsia, nausea and diarrhea with an incidence of approximately 4% of the patients treated with Piroxicam over one year. An increase in symptoms may occur in the elderly or debilitated patients, sometimes almost occurring as spontaneous gastrointestinal fatal events. Long term administration may cause papillary necrosis in the kidney along with interstitial nephritis and nephritic syndrome with hematuria and proteinuria (blood and protein in the urine, respectively). Prostaglandin synthesis which causes the negative and painful inflammatory process is also beneficial and necessary for maintenance of renal blood flow, this drug and the other NSAIDs may reduce renal flow thus causing renal decompensation and produced cardiovascular effect. Elevated liver enzymes may occur with long term usage in 15% of the patients and if persistent upon discontinuation of values 3 times the normal, especially SGPT (ALT) should be evaluated further for liver disease. Liver disease may present as persistent pruritis, rash, eosinophilia (elevated particular blood cells), or possible jaundice and hepatitis.
Other systemic reactions may be fatigue, fever, a vesicular bullous (an elevated blistery) dermatitis, arthralgias, with exfoliative (peeling) dermatitis. Edema, blurred vision, disrupted sleep patterns, hallucinations, painful urination, cardiac palpitations, dyspnea(difficulty or labored breathing), altered hearing, mental confusion, fungus of nails(onychomycosis) alopecia(loss of hair) mood alterations are other possible reactions to Piroxicam.
Drugs that interact with Piroxicam are based upon its highly protein binding chemistry and include aspirin as previously discussed, Coumadin patients should be cautiously monitored if prescribed Piroxicam and used only if its benefits outweigh the possible significant serious side effects of bleeding. Antacids have no plasma depleting effects on Piroxicam, and may reduced gastric irritation along with administration of the drug within the hour after a meal.
DOSING
The dosage of Piroxicam is 20mg orally daily with food/antacid if deemed necessary or for better tolerance the 10mg capsules may be given twice daily with food. The long half life as described, accounts for the 7-10 day establishment of steady-state plasma levels and pharmaceutically beneficial results, so the results should not be assessed for two weeks.
REFERENCES
PDR, PHYSICIANS’ DESK REFERENCE, EDITION 59, 1999
801 PRESCRIPTION DRUGS, GOOD EFFECTS, SIDE EFFECTS & NATURAL HEALING ALTERNATIVES
My personal practice experience with Piroxicam, Feldene has been favorable. Ironically, I found some patients tolerating this drug better than some of the other drugs, such as the selective prostaglandin synthesis inhibitors. At the 20mg once daily dose with food, it provided the needed relief in those patients with mild to moderate pain of tendonitis, ankle sprains usually within a 7-9 day window.
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