European journal of rheumatology and inflammation最新文献

Growing evidence suggests that nonsteroidal anti-inflammatory drugs (NSAIDs), while able to alleviate inflammation, may damage articular cartilage, though both chondrodestructive and chondroprotective activities have been observed with different NSAIDs. Experiments conducted on explants of normal and osteoarthritic human cartilage have shown that certain NSAIDs at pharmacologic concentrations achievable in man consistently inhibit glycosaminoglycan (GAG) synthesis. The addition of the prostaglandin E1 analogue misoprostol consistently reversed these inhibitory effects in a dose-related manner. Paradoxically, with some NSAIDs, such as diclofenac and aspirin, misoprostol was also able to enhance GAG synthesis above control levels, especially in osteoarthritic cartilage. This supports findings from other work that NSAIDs exert effects other than through inhibition of cyclooxygenase, direct action on cell membranes being one of these alternative mechanisms of action. Additionally it is interesting to note and may be of clinical relevance that misoprostol on its own also stimulates GAG synthesis in explants of human osteoarthritic cartilage whilst exerting no apparent effect on healthy cartilage with a normal GAG turnover. With regard to renal aspects, the effects of NSAIDs are readily explicable in terms of interference with prostanoid synthesis. The consequent inhibition exerted on vasodilatory prostaglandins (PGs), which oppose vasoconstrictor action induced by substances such as thromboxane or leukotrienes, upsets the balance that maintains renal function. In situations in which there is reduced renal reserve, reduction of renal PG synthesis by NSAIDs will adversely affect maintenance of renal blood flow and glomerular filtration rate and excretion of sodium, potassium, and water. Patients with alcoholic cirrhosis manifest this type of compromised renal function and in them misoprostol reverses the adverse effects of indomethacin on renal hemodynamics and partially reverses indomethacin-induced renal sodium retention. Although the clinical significance of these data is not yet established, exogenous administration of specific PGs may be able to minimize the deleterious actions of NSAIDs.

Piroxicam beta-cyclodextrin is a novel inclusion complex in which the piroxicam molecule has higher wettability and faster dissolution characteristics than plain piroxicam. Pharmacokinetic studies comparing piroxicam beta-cyclodextrin with plain piroxicam have been carried out in both patients and healthy subjects. The absorption rate of piroxicam from the complex, determined using tmax, absorption rate constant (Ka) and plasma concentrations at 15 min and 30 min post-dose, is considerably faster than that for plain piroxicam. This difference, that can be demonstrated with both tablet and sachet formulations, is still present during repeated dose administration and when the drugs are administered after food. After absorption from piroxicam beta-cyclodextrin formulations, the kinetic disposition of piroxicam and bioavailability parameters are identical to those for plain piroxicam. The more rapid rise in piroxicam plasma concentrations and the reduced contact time of piroxicam in the upper gastrointestinal-tract may be reasons for the reduced incidence of gastrointestinal complaints and gastrointestinal bleeding and the rapid attainment of pain relief with piroxicam beta-cyclodextrin. The most rapid relief of pain will be achieved using piroxicam beta-cyclodextrin sachets administered in the fasting state, since piroxicam is immediately bioavailable in this formulation and the onset of action is similar to that for injectable piroxicam.

Piroxicam-beta-cyclodextrin (PBC), a complex of piroxicam with beta-cyclodextrin, was developed with the aim of improving the hydrosolubility and bioavailability of piroxicam. The complex is more rapidly absorbed, with a consequent reduction in the time of contact of piroxicam with the gastric and duodenal mucosa. It is hoped that the shorter contact time might reduce the local toxicity of piroxicam, but it is also possible that transiently higher local concentrations of the drug might worsen the injury to the gastro-duodenal mucosa. Four studies have been conducted in healthy volunteers in order to investigate the effects of PBC on the gastro-intestinal tract. In 3 of these trials, all of similar design, PBC (containing 20 mg of piroxicam) was compared with piroxicam 20mg and placebo given once daily with assessment of faecal blood loss using the 51Cr-labelled red-cell technique, and endoscopic appearance of gastroduodenal mucosa before and after 28 consecutive days of treatment. One study showed a significant difference in respect of faecal blood loss towards the end of the 4-week study period favouring PBC over piroxicam, while the 2 others showed comparable but non-significant trends in favour of PBC. In a fourth study, 32 non-patient volunteers received either piroxicam 20mg once daily; PBC 20mg equivalence; indomethacin 50mg twice daily; or placebo. The treatment was given double blind for 14 days. Endoscopy was performed and gastric potential differences were measured by neutral observers before and at the end of treatment. There were no significant differences in the endoscopic scores between the active treatment groups. The gastric potential difference showed greater changes with indomethacin and piroxicam than with placebo and PBC.(ABSTRACT TRUNCATED AT 250 WORDS)

The clinical relevance of piroxicam-beta-cyclodextrin (PBC) in the long-term treatment of osteoarthritis and rheumatoid arthritis is reviewed. Two hundred and twenty-five patients--one hundred with rheumatoid arthritis and one hundred and twenty five with osteoarthritis--were enrolled in a double-blind, randomised, controlled study versus piroxicam. Drugs were administered once-daily, for twelve weeks. The indices of efficacy (pain intensity, severity of inflammation, functional impairment evaluated at 0,2,4,8 and 12 weeks showed the good analgesic effect of piroxicam without significant differences between its two formulations. Tolerance appeared to be better in the group of patients treated with PBC than in the one treated with piroxicam. Both the incidence and severity of side effects were lower for patients treated with PBC. The majority of side effects were related to the gastrointestinal tract. The study suggests that PBC, used in the long term treatment of rheumatic diseases, improves the safety of piroxicam without affecting its efficacy. In another study, thirty patients with chronic osteoarthritis were randomly assigned to receive PBC or tenoxicam daily for eight weeks. Both drugs effectively reduced pain, inflammation, and functional limitation of the affected joints. Endoscopy revealed minor post-treatment mucosal lesions; these tended to be less severe with PBC than with tenoxicam. The clinical experience in the long-term treatment of rheumatic conditions indicates that the microencapsulation of piroxicam as piroxicam-beta-cyclodextrin has provided a new drug with a superior tolerability compared to the parent compound without affecting its high efficacy on the symptoms of the primary disease.

Arthrotec (Searle) is a new concept in NSAID therapy that provides powerful anti-inflammatory efficacy with enhanced upper GI safety. Arthrotec comprises an enteric-coated core of diclofenac sodium (50 mg) surrounded by a mantle of misoprostol (200 mcg). Two multicentre trials evaluated the efficacy of Arthrotec in rheumatoid arthritis (RA) and osteoarthritis (OA) patients who were randomised to receive either Arthrotec or diclofenac. The results of all arthritis assessments showed Arthrotec to be as effective as diclofenac in treating the signs and symptoms of RA and OA. Two endoscopic studies compared the antiarthritic efficacy and gastroduodenal safety of Arthrotec and diclofenac. In a 12-week study of RA patients, the antiarthritic efficacy of Arthrotec was equivalent to diclofenac; in addition, 60% fewer patients taking Arthrotec experienced ulcers than did those taking diclofenac (4.4% Arthrotec vs 11.1% diclofenac: P = 0.034). In a 4-week study of OA patients, Arthrotec's efficacy was equivalent to that of diclofenac and the Arthrotec group developed no ulcers, while 3.6% of the diclofenac group had ulcers (P = 0.015). In a trial conducted to compare the efficacy and upper gastroduodenal safety of Arthrotec with those of piroxicam and naproxen, patients with OA received either Arthrotec BID piroxicam 10 mg BID, or naproxen 375 BID for 4 weeks. Arthritis assessments showed Arthrotec to be at least as effective as piroxicam and naproxen in treating OA. Post-treatment endoscopy data indicated that gastroduodenal ulcers developed in 1.5% of patients receiving Arthrotec, 10.3% of patients receiving piroxicam, and 8.6% patients in the naproxen group.(ABSTRACT TRUNCATED AT 250 WORDS)

The association between use of nonsteroidal anti-inflammatory drugs (NSAIDs) and the development of upper gastrointestinal (GI) damage is well established. Studies have indicated that 12-30% of NSAID users will develop gastric ulcers and that 2-19% will develop duodenal ulcers. Furthermore, many NSAID-induced ulcers are "silent" and are only discovered when complications occur. When possible, the most effective method of preventing NSAID-induced gastropathy is discontinuation of NSAIDs or a reduction in the NSAID dosage. For patients who require continued NSAID therapy, four classes of drugs have been evaluated for their potential protective effects against NSAID-induced gastroduodenal damage:H2-receptor antagonists (eg, ranitidine), proton pump inhibitors (eg, omeprazole), acid-barrier compounds (eg, sucralfate), and prostaglandin E1 analogues (eg, misoprostol). H2-receptor antagonists have not been shown to be effective in preventing NSAID-induced gastric ulcers, and sucralfate has not been shown to be effective in preventing NSAID-induced gastric or duodenal ulcers. Similarly, newer proton pump inhibitors, such as omeprazole, do not appear to protect the stomach against NSAID-induced damage. In contrast, misoprostol has proven its efficacy in preventing both gastric and duodenal ulcers in arthritis patients taking NSAID therapy.

Piroxicam-beta-cyclodextrin is a novel NSAID; it is a supermolecular inclusion complex designed to improve the risk:benefit ratio of piroxicam. In animal studies it has been shown to be as effective as piroxicam as an anti-inflammatory and analgesic agent but with a more rapid onset of action and reduced gastropathic effects.

The secondary gastrointestinal effects associated with the use of nonsteroidal anti-inflammatory drugs (NSAIDs) are well documented in the medical literature. The "iatrogenic" cost arising from the treatment of these secondary effects, however, is less well known. Existing epidemiologic and clinical studies report that the cost of NSAIDs is multiplied by a coefficient that ranges from 1.36 to 3 when the cost of treating the induced gastroduodenal damage is taken into account. A simple methodology has been developed to calculate the "shadow price" of an NSAID by incorporating the costs of treating the gastroduodenal damage, thus yielding a figure that reflects the real economic burden of NSAID therapy. Using study data from seven countries, the cost effectiveness of prophylactic treatment with misoprostol--a prostaglandin analogue whose efficacy has been proven in the prevention of gastroduodenal ulcers in arthritic patients treated with NSAIDs--is reviewed. In the majority of cases, the financial benefits of preventing the ulcers equal or surpass the cost of prevention.