Elevations of ALT or AST (three or more times the upper limit of normal ) have been reported in approximately 1% of NSAID-treated patients in clinical trials. In addition, rare, sometimes fatal, cases of severe hepatic injury, including fulminant hepatitis, liver necrosis, and hepatic failure have been reported.
Elevations of ALT or AST (less than three times ULN) may occur in up to 15% of patients treated with NSAIDs including Piroxsal.
Inform patients of the warning signs and symptoms of hepatotoxicity (e.g., nausea, fatigue, lethargy, diarrhea, pruritus, jaundice, right upper quadrant tenderness, and "flu-like" symptoms). If clinical signs and symptoms consistent with liver disease develop, or if systemic manifestations occur (e.g., eosinophilia, rash, etc.), discontinue FELDENE immediately, and perform a clinical evaluation of the patient.
Dosage Forms and Strengths
Piroxsal capsules USP, 10 mg are white to off-white powder filled in size '2' empty hard gelatin capsules with dark-green opaque cap imprinted with '742' with white ink and light-green opaque body.
Piroxsal capsules USP, 20 mg are white to off-white powder filled in size '2' empty hard gelatin capsules with dark-green opaque cap imprinted with '743' with white ink and dark-green opaque body.
Piroxsal disease interactions
There are 12 disease interactions with Piroxsal which include:
Piroxsal is considered the standard of care for TCC in dogs and may have specific advantages over other NSAIDs.
Inducible cyclooxygenase 2 (COX-2) enzymes are not expressed in the normal urinary bladder but are upregulated in tumors including TCC. a.
COX-2 is expressed in both primary and metastatic TCC.
COX-2 enzymes and their product, prostaglandin E2 (PGE2), a potent immunosuppressive compound, promote tumor growth by preventing apoptosis, stimulating tumor cell proliferation, and promoting angiogenesis.
PGE2 concentrations are increased in the bladder mucosa of patients with TCC growth as compared with normal bladder mucosa.
Piroxsal, a COX enzyme inhibitor, has antitumor activity and decreases the size of tumors when used in dogs with TCC. a.
The mechanism of action is not based on cytotoxicity.
COX inhibition may provide some immunomodulation by suppressing PGE2 and thereby inducing apoptosis, inhibiting angiogenesis, and decreasing tumor cell proliferation.
Decreased inflammation alone cannot account for the partial and complete remissions achieved in vivo.
Piroxsal provides good control of clinical signs and improves quality of life in some patients. Owners usually note increased activity and improvement in the attitude of their pet while the dog is receiving Piroxsal.
Clinical studies of Piroxsal in dogs with TCC indicate an overall response rate of 16%.
Piroxsal provides good control of clinical signs, improving the quality of life in many dogs with TCC.
Complete remission is achieved in 4% of treated dogs.
Partial remission is observed in 13%.
Disease remained stable in 58%.
Progressive disease was noted in 25%.
Gastrointestinal toxicity occurred in 17% of treated dogs. a.
Signs of toxicity included anorexia, melena, and vomiting.
Gastroprotectants may be used in combination with Piroxsal. (1)
H2 receptor blockers.
Proton pump inhibitors.
Misoprostol (prostaglandin E1 analogue).
Acute renal failure is a potential complication of nonsteroidal anti-inflammatory drugs (NSAIDs). Renal function should be monitored regularly while prescribing this medication for dogs with TCC.
Piroxsal is used at a dosage of 0.3 mg/kg orally once daily if tolerated. It is given every other day to limit adverse effects in some patients. a.
Only 10 mg and 20 mg capsules are available.
Compounding pharmacies can reformulate this medication into varying concentrations to accommodate smaller animals.
Median survival with Piroxsal as the sole form of treatment is approximately 6 months. About 20% of treated dogs survived for one year.
Piroxsal may have unique effects against TCC as compared with other NSAIDs. This possibility has not been studied in TCC, but it is well known that each NSAID has its own profile of effect against a variety of other tumors in experimental studies in mice.
Anemia has occurred in NSAID-treated patients. This may be due to occult or gross blood loss, fluid retention, or an incompletely described effect on erythropoiesis. If a patient treated with Piroxsal has any signs or symptoms of anemia, monitor hemoglobin or hematocrit.
NSA > .
Getting the most from your treatment
- Try to avoid the gel coming into contact with your eyes, and do not apply it to any broken or irritated areas of your skin. If this does happen by accident, wash it off with warm water as soon as possible.
- It is important that you don't cover any area of skin that has been treated with the gel with any dressings or bandages. This is because more Piroxsal may be absorbed by your skin than is intended, and this could lead to unwanted effects.
- Piroxsal could cause your skin to become more sensitive to sunlight than normal. Do not use sunbeds, and protect any treated areas from strong sunlight until you know how your skin reacts.
Mechanism of action – additional information
Piroxsal is a member of the oxicam class of NSAIDs.
Piroxsal (pir ox' i kam) belongs to the oxicam family, which is a class of enolic acids structurally unrelated to other NSAIDs. Piroxsal, like other NSAIDs, acts through inhibition of tissue cyclooxygenases (Cox-1 and -2) leading to a decrease in synthesis of pro-inflammatory prostaglandins, which are potent mediators of pain and inflammation. Piroxsal has analgesic as well as antipyretic and antiinflammatory activities. Piroxsal was approved for use in the United States in 1982 and is still widely used, with several million prescriptions filled yearly. Current indications include rheumatoid arthritis and osteoarthritis. Piroxsal is available as capsules of 10 and 20 mg in several generic forms as well as under brand names such as Feldene, Novo-Pirocam and Nu-Pirox. The recommended dose is 10 to 20 mg orally once daily. Piroxsal is available by prescription only. Other oxicam NSAIDs include meloxicam, tenoxicam, and droxicam, the latter two being available in other countries, but not the United States. As with other NSAIDs, Piroxsal is generally well tolerated, but side effects can include headache, dizziness, somnolence, dyspepsia, abdominal discomfort, diarrhea, peripheral edema and hypersensitivity reactions.
Blood pressure drugs
Taking certain blood pressure drugs with Piroxsal might make those drugs not work as well. Examples of these drugs include:
- angiotensin-converting enzyme (ACE) inhibitors
- diuretics (water pills)
Piroxsal capsules, USP contain Piroxsal, USP which is a member of the oxicam group of nonstero >N -2-pyr >H -1,2,-benzothiazine-3-carboxam >15 H 13 N 3 O 4 S and it has the following structural formula: