Oxicams piroxicam

Oxicams. Piroxicam lia.s a long half-life and only requires a single daily dose to be administered. It may be associated w ilh a particularly high incidence of gasiroimestinal bleeding in the elderly. 

Oxicams, e.g. piroxicam, tenoxicam, meloxicam and lornoxicam are non-specific inhibitors of COX. Like diclofenac, meloxicam inhibits COX-2 ten times more potently than COX-1. This property can be exploited clinically with doses up to 7.5 mg per day, but at higher doses COX-1-inhibition becomes clinically relevant. Since the dose of meloxicam commonly used is 15 mg daily, this agent cannot be regarded as a COX-2-selective NS AID and considerable caution needs to be exercised when making comparisons between the actions of meloxicam and those of other conventional NSAIDs. The average daily dose in anti-rheumatic therapy is 20 mg for piroxicam and tenoxicam, 7.5-15 mg for meloxicam and 12-16 mg for lornoxicam. Oxicams have long elimination half-lives (lornoxicam 3-5 h, meloxicam - 20 h, piroxicam 40 h and tenoxicam 70 h). 

Piroxicam (Feldene) is the prototypical oxicam derivative, with analgesic, antipyretic, and antiinflammatory properties. Its long half-life (45 hours) favors compliance, since only one dose per day is given. Side effects are similar to those encountered with other NSAIDs gastric disturbances, tinnitus, and headache. Piroxicam is indicated for inflammatory and rheumatoid conditions. 

The most biologically active members of the benzothiazines, known as the oxicams, include piroxicam (Feldene ) 21, meloxicam (Mobic ) 22, and tenoxicam 23 which have a 1,2-benzothiazine 1,1,4-trioxide structure. Recently, the... 

Piroxicam, an oxicam (Figure 36-1), is a nonselective COX inhibitor that at high concentrations also inhibits polymorphonuclear leukocyte migration, decreases oxygen radical production, and inhibits lymphocyte function. Its long half-life (Table 36-1) permits once-daily dosing. 

Tenoxicam is an oxicam similar to piroxicam and shares its nonselective COX inhibition, long half-life (72 hours), efficacy, and toxicity profile. It is available abroad but not in the USA. 

Piroxicam (84, Feldene in the US), a non-selective COX inhibitor with both analgesic and antipyretic properties, is one of the most used NSAIDs and serves as prototype of the oxicam family. This drug is utilized to relieve the symptoms of arthritis, menstrual pains or cramps and fever. It is also used in veterinary medicine to treat certain neoplasias expressing COX receptors, such as bladder, colon and prostate cancers. Variation on the structure of piroxicam has produced several other analogues with the benzene ring replaced by a thiophene ring and/or derivatives of the amide moiety, including meloxicam (85, a thiazole amide), isoxicam (86, an isoxazole amide), tenoxicam (87a, a thiophene derivative) and lornoxicam (87b, a chlorothiophene derivative). 

The oxicam NSAID isoxicam has a shorter half-life (30 hours) than piroxicam. However, there are large variations in half-life, clearance, and mean steady-state plasma concentrations. Except for edema, the incidence of adverse effects is unrelated to age (1). 

Oxicams are a class of recently introduced enolic acid derivatives, including ineloxicain, piroxlcam and tenoxicam. So far only piroxicam has any extensive usage and is mainly used to treat rheumatoid and osteoarthritis, and for musculoskeletal pain. 

In recent years there has been a dramatic increase in the number of literature references to 1,2-benzothiazines (1) and 2,1-benzothiazines (2). Prior to 1956, the only reference was that published in 1923 by von Braun.1 In the last 15 years, however, many publications have presented interesting chemistry and important applications. Much of the literature deals with anti-inflammatory 1,2-benzothiazines ( oxicams ) such as piroxicam. The... 

The outstanding anti-inflammatory activity exhibited by sudoxicam (20), and piroxicam (29) (see Section II,D) has prompted exploration of structure-activity relationships (SAR) of oxicam anti-inflammatory agents. This... 

Mefenamic acid, and piroxicam and tenoxicam have a spectmm of side effects between that of aspirin and the ibuprofen type. The oxicams have a markedly longer duration of action than the majority of other NSAIDs and are therefore useful in chronic pain. 

Oxicams are a series of A-heterocyclic carboxamides of 1,2-benzothiazine 1,1-dioxides. Piroxicam... 

Few reports of therapeutically significant interactions of oxicams with other drugs have appeared. Concurrent administration of aspirin has been shown to reduce piroxicam plasma levels by approximately 20%, whereas the anticoagulant effect of acenocoumarin is potentiated, presumably as a result of plasma protein displacement. 

Lombardino JG, Wiseman EH. Piroxicam and other anti-inflammatory oxicams. Med Res Rev 1982 2 127-152. 

The starting material for meloxicam [201] and piroxicam [202], two oxicams from Thomae GmbH, respectively Pfizer, is the sweetener saccharin, which is accessible in a few steps from toluene according to the Remsen-Fahlberg procedure (Fig. 5.91). [203, 204]... 

Piroxicam is a non-steroidal anti-iflammatory drug, of the oxicam class. A contact and photocontact sensitizer, which induced contact dermatitis in a physical therapist. Piroxicam generally cross reacts with thio-salicylic acid and also with thiomersal. Cross sensitivity is not observed to tenoxicam. 

The simultaneous assay of six oxicam NSAIDs (piroxicam, tenoxicam, lornox-icam, cinnoxicam, isoxicam (ISX meloxicam) in pharmaceutical preparations was accomplished on a C g column (A = 320 nm for cinnoxicam and 360 nm for all others) using a 715/220/50/15 water (15/85 50mM Tris/50mM acetic acid)/ acetonitrile/THF/water (8.8 g ammonium phosphate with 25 mM tetrabutylammo-nium hydroxide to pH 7.5 with H3PO4) mobile phase [1333]. Good peak shape, excellent resolution, and elution complete in 25 min were obtained. The calibration curve was reported as 1-11 mg/L with detection limits of 3 ng/injection (S/N = 3) and quantitation limits of 10 ng/injection (S/N = 10). 

Acetic add class (sulindac), phenylpropionic class (flurbiprofen), anthranilic add class (flufenamic add), oxicam class (piroxicam). 

Oxicams are characterized by rich dynamic structural features. Such characteristics reflected in an emission behaviour highly sensitive to the environment. Of particular concern, the inclusion of piroxicam (7, Fig. 2) within CD nanocavities at various pH values [44-47]. The goal was to clarify the reported differences in stoichiometry of the formed inclusion complexes. They found that the pH-dependent self-association phenomena, detected in both alkaline and... 

FIGURE 13.11 Structures of piroxicam and meloxicam (the general class of oxicams). 

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