Re: Pirox Fish Bot 3.3 5a New Hit
Julia Heaslet
There are 380 drugs known to interact withpiroxicam, along with12 disease interactions, and3 alcohol/food interactions.Of the total drug interactions,94 are major, 275 are moderate, and11 are minor.
FELDENE (piroxicam) capsule is a nonsteroidal anti-inflammatory drug, available as maroon and blue #322 10 mg capsules and maroon #323 20 mg capsules for oral administration. The chemical name is 4-hydroxyl-2- methyl-N-2-pyridinyl-2H-1,2,-benzothiazine-3-carboxamide 1,1-dioxide. The molecular weight is 331.35. Its molecular formula is C15H13N3O4S, and it has the following chemical structure.
There is no consistent evidence that concurrent use of aspirin mitigates the increased risk of serious CV thrombotic events associated with NSAID use. The concurrent use of aspirin and an NSAID, such as piroxicam, increases the risk of serious gastrointestinal (GI) events [see WARNINGS AND PRECAUTIONS].
Additionally, fluid retention and edema have been observed in some patients treated with NSAIDs. Use of piroxicam may blunt the CV effects of several therapeutic agents used to treat these medical conditions (e.g., diuretics, ACE inhibitors, or angiotensin receptor blockers [ARBs]) [see DRUG INTERACTIONS].
Piroxicam has been associated with anaphylactic reactions in patients with and without known hypersensitivity to piroxicam and in patients with aspirin-sensitive asthma [see CONTRAINDICATIONS and WARNINGS AND PRECAUTIONS].
NSAIDs, including piroxicam, can cause serious skin adverse reactions such as exfoliative dermatitis, Stevens-Johnson Syndrome (SJS), and toxic epidermal necrolysis (TEN), which can be fatal. These serious events may occur without warning. Inform patients about the signs and symptoms of serious skin reactions, and to discontinue the use of FELDENE at the first appearance of skin rash or any other sign of hypersensitivity. FELDENE is contraindicated in patients with previous serious skin reactions to NSAIDs [see CONTRAINDICATIONS].
Reproductive studies in which rats were administered piroxicam at doses of 2, 5, or 10 mg/kg/day (up to 5 times the MRHD of 20 mg based on mg/m body surface area [BSA]) revealed no impairment of male or female fertility.
Data from observational studies regarding other potential embryofetal risks of NSAID use in women in the first or second trimesters of pregnancy are inconclusive. In animal reproduction studies in rats and rabbits, there was no evidence of teratogenicity at exposures up to 5 and 10 times the maximum recommended human dose (MRHD), respectively. In rat studies with piroxicam, fetotoxicity (postimplantation loss) was observed at exposures 2 times the MRHD, and delayed parturition and an increased incidence of stillbirth were noted at doses equivalent to the MRHD of piroxicam. Based on animal data, prostaglandins have been shown to have an important role in endometrial vascular permeability, blastocyst implantation, and decidualization. In animal studies, administration of prostaglandin synthesis inhibitors such as piroxicam, resulted in increased pre-and post-implantation loss. Prostaglandins also have been shown to have an important role in fetal kidney development. In published animal studies, prostaglandin synthesis inhibitors have been reported to impair kidney development when administered at clinically relevant doses.
There are no studies on the effects of FELDENE during labor or delivery. In animal studies, NSAIDS, including piroxicam inhibit prostaglandin synthesis, cause delayed parturition, and increase the incidence of stillbirth.
Pregnant rats administered piroxicam at 2, 5, or 10 mg/kg/day during the period of organogenesis (Gestation Days 6 to 15) demonstrated increased post-implantation losses with 5 and 10 mg/kg/day of piroxicam (equivalent to 2 and 5 times the MRHD, of 20 mg respectively, based on a mg/m body surface area [BSA]). There were no drug-related developmental abnormalities noted in offspring. Gastrointestinal tract toxicity was increased in pregnant rats in the last trimester of pregnancy compared to non-pregnant rats or rats in earlier trimesters of pregnancy. Pregnant rabbits administered piroxicam at 2, 5, or 10 mg/kg/day during the period of organogenesis (Gestation Days 7 to 18) demonstrated no drug-related developmental abnormalities in offspring (up to 10 times the MRHD based on a mg/m BSA).
In a pre-and post-natal development study in which pregnant rats were administered piroxicam at 2, 5, or 10 mg/kg/day on Gestation Day 15 through delivery and weaning of offspring, reduced weight gain and death were observed in dams at 10 mg/kg/day (5 times the MRHD based on a mg/m BSA) starting on Gestation Day 20. Treated dams revealed peritonitis, adhesions, gastric bleeding, hemorrhagic enteritis and dead fetuses in utero. Parturition was delayed and there was an increased incidence of stillbirth in all piroxicam-treated groups (at doses equivalent to the MRHD). Postnatal development could not be reliably assessed due to the absence of maternal care secondary to severe maternal toxicity.
The long plasma half-life of piroxicam should be considered when treating an overdose with piroxicam. Forced diuresis, alkalinization of urine, hemodialysis, or hemoperfusion may not be useful due to high protein binding.
Piroxicam is a potent inhibitor of prostaglandin (PG) synthesis in vitro. Piroxicam concentrations reached during therapy have produced in vivo effects. Prostaglandins sensitize afferent nerves and potentiate the action of bradykinin in inducing pain in animal models. Prostaglandins are mediators of inflammation. Because piroxicam is an inhibitor of prostaglandin synthesis, its mode of action may be due to a decrease of prostaglandins in peripheral tissues.
The pharmacokinetics of piroxicam have been characterized in healthy subjects, special populations and patients. The pharmacokinetics of piroxicam are linear. Proportional increase in exposure is observed with increasing doses. The prolonged half-life (50 hours) results in the maintenance of relatively stable plasma concentrations throughout the day on once daily doses and significant accumulation upon multiple dosing. Most patients approximate steady state plasma levels within 7 to 12 days. Higher levels, which approximate steady state at two to three weeks, have been observed in patients in whom longer plasma half-lives of piroxicam occurred.
Piroxicam is well absorbed following oral administration. Drug plasma concentrations are proportional for 10 mg and 20 mg doses and generally peak within three to five hours after administration. A single 20 mg dose generally produces peak piroxicam plasma levels of 1.5 mcg/mL to 2 mcg/mL, while maximum drug plasma concentrations, after repeated daily administration of 20 mg piroxicam, usually stabilize at 3 mcg/mL to 8 mcg/mL.
With food there is a slight delay in the rate but not the extent of absorption following oral administration. The concomitant administration of antacids (aluminum hydroxide or aluminum hydroxide with magnesium hydroxide) have been shown to have no effect on the plasma levels of orally administered piroxicam.
The apparent volume of distribution of piroxicam is approximately 0.14 L/kg. Ninety nine percent of plasma piroxicam is bound to plasma proteins. Piroxicam is excreted into human milk. The presence in breast milk has been determined during initial and long term conditions (52 days). Piroxicam appeared in breast milk at approximately 1% to 3% of the maternal concentration. No accumulation of piroxicam occurred in milk relative to that in plasma during treatment.
Metabolism of piroxicam occurs by hydroxylation at the 5 position of the pyridyl side chain and conjugation of this product; by cyclodehydration; and by a sequence of reactions involving hydrolysis of the amide linkage, decarboxylation, ring contraction, and N-demethylation. In vitro studies indicate cytochrome P4502C9 (CYP2C9) as the main enzyme involved in the formation to the 5'-hydroxypiroxicam, the major metabolite [see CLINICAL PHARMACOLOGY]. The biotransformation products of piroxicam metabolism are reported to not have any anti-inflammatory activity.
Piroxicam and its biotransformation products are excreted in urine and feces, with about twice as much appearing in the urine as in the feces. Approximately 5% of a FELDENE dose is excreted unchanged. The plasma half-life (t) for piroxicam is approximately 50 hours.
The effects of hepatic disease on piroxicam pharmacokinetics have not been established. However, a substantial portion of piroxicam elimination occurs by hepatic metabolism. Consequently, patients with hepatic disease may require reduced doses of piroxicam as compared to patients with normal hepatic function.
Piroxicam pharmacokinetics have been investigated in patients with renal insufficiency. Studies indicate patients with mild to moderate renal impairment may not require dosing adjustments. However, the pharmacokinetic properties of piroxicam in patients with severe renal insufficiency or those receiving hemodialysis are not known.
When piroxicam was administered with aspirin, its protein binding was reduced, although the clearance of free FELDENE was not altered. Plasma levels of piroxicam were decreased to approximately 80% of their normal values when FELDENE was administered (20 mg/day) in conjunction with aspirin (3900 mg/day). The clinical significance of this interaction is not known [see DRUG INTERACTIONS].
Veterinarians commonly prescribe piroxicam to treat a type of bladder cancer called transitional cell carcinoma (TCC) in dogs and cats. Piroxicam can also help treat other types of cancer, including mammary (breast) tumors, lung tumors, and squamous cell carcinoma.
Veterinarians primarily prescribe piroxicam for its anti-tumor effects. The exact way that piroxicam works against tumors is unknown, but it appears to treat cancer in several ways. Piroxicam acts on the immune system by helping it identify and kill cancer cells. Piroxicam, like other NSAIDs, works by inhibiting an enzyme called cyclooxygenase, or COX, which produces pro-inflammatory chemicals. Suppressing COX activity reduces inflammation that is caused by tumor cells. Piroxicam appears to also inhibit blood vessel growth in tumors.