Comparison of faecal blood loss, upper gastrointestinal mucosal integrity and symptoms after piroxicam beta-cyclodextrin, piroxicam and placebo administration

Piroxicam-β-cyclodextrin: a GI safer piroxicam

Although NSAIDs are very effective drugs, their use is associated with a broad spectrum of adverse reactions in the liver, kidney, cardiovascular (CV) system, skin and gut. Gastrointestinal (GI) side effects are the most common and constitute a wide clinical spectrum ranging from dyspepsia, heartburn and abdominal discomfort to more serious events such as peptic ulcer with life-threatening complications of bleeding and perforation. The appreciation that CV risk is also increased further complicates the choices of physicians prescribing anti-inflammatory therapy. Despite prevention strategies should be implemented in patients at risk, gastroprotection is often underused and adherence to treatment is generally poor. A more appealing approach would be therefore to develop drugs that are devoid of or have reduced GI toxicity. Gastro-duodenal mucosa possesses many defensive mechanisms and NSAIDs have a deleterious effect on most of them. This results in a mucosa less able to cope with even a reduced acid load. NSAIDs cause gastro-duodenal damage, by two main mechanisms: a physiochemical disruption of the gastric mucosal barrier and systemic inhibition of gastric mucosal protection, through inhibition of cyclooxygenase (COX, PG endoperoxide G/H synthase) activity of the GI mucosa. However, against a background of COX inhibition by anti-inflammatory doses of NSAIDs, their physicochemical properties, in particular their acidity, underlie the topical effect leading to short-term damage. It has been shown that esterification of acidic NSAIDs suppresses their gastrotoxicity without adversely affecting anti-inflammatory activity. Another way to develop NSAIDs with better GI tolerability is to complex these molecules with cyclodextrins (CDs), giving rise to so-called “inclusion complexes” that can have physical, chemical and biological properties very different from either those of the drug or the cyclodextrin. Complexation of NSAIDs with β-cyclodextrin potentially leads to a more rapid onset of action after oral administration and improved GI tolerability because of minimization of the drug gastric effects. One such drug, piroxicam-β-cyclodextrin (PBC), has been used in Europe for 25 years. Preclinical and clinical pharmacology of PBC do show that the β-cyclodextrin inclusion complex of piroxicam is better tolerated from the upper GI tract than free piroxicam, while retaining all the analgesic and anti-inflammatory properties of the parent compound. In addition, the drug is endowed with a quick absorption rate, which translates into a faster onset of analgesic activity, an effect confirmed in several clinical studies. An analysis of the available trials show that PBC has a GI safety profile, which is better than that displayed by uncomplexed piroxicam. Being an inclusion complex of piroxicam, whose CV safety has been pointed out by several observational studies, PBC should be viewed as a CV safe anti-inflmmatory compound and a GI safer alternative to piroxicam. As a consequence, it should be considered as a useful addition to our therapeutic armamentarium.

Cyclodextrin-based pharmaceutics: past, present and future

Cyclodextrins are cyclic oligomers of glucose that can form water-soluble inclusion complexes with small molecules and portions of large compounds. These biocompatible, cyclic oligosaccharides do not elicit immune responses and have low toxicities in animals and humans. Cyclodextrins are used in pharmaceutical applications for numerous purposes, including improving the bioavailability of drugs. Current cyclodextrin-based therapeutics are described and possible future applications discussed. Cyclodextrin-containing polymers are reviewed and their use in drug delivery presented. Of specific interest is the use of cyclodextrin-containing polymers to provide unique capabilities for the delivery of nucleic acids.

Meta-analysis of dyspepsia and nonsteroidal antiinflammatory drugs

OBJECTIVE

Nonsteroidal antiinflammatory drug (NSAID) use is a known risk factor for gastrointestinal (GI) perforations, ulcers, and bleeds, but there are limited data on its association with the very common symptom of dyspepsia. Using published and unpublished data sources, we sought to determine estimates of the risks of dyspepsia associated with NSAIDs.

METHODS

We searched computerized databases (1966-1998) for primary studies of NSAIDs reporting on GI complications. We also obtained Food and Drug Administration (FDA) new drug application reviews for the 5 most common NSAIDs. We included studies reporting defined upper GI outcomes among subjects (>17 years old) who used oral NSAIDs for more than 4 days. Two reviewers evaluated 4,881 published titles, identifying 55 NSAID versus placebo randomized controlled trials (RCTs), 37 unpublished (FDA data) placebo-controlled RCTs; 86 NSAID versus NSAID RCTs (sample size >or=50); and 103 observational studies.

RESULTS

The majority of clinical trials were of good quality. Meta-regression identified an increased risk of dyspepsia for users of specific NSAIDs (adjusted odds ratio [OR] of indomethacin, meclofenamate, piroxicam = 2.8), and for high dosages of other NSAIDs (OR = 3.1), but not for other NSAIDs regardless of dosage (OR = 1.1). Dyspepsia was not reported as an outcome in the case control or cohort studies.

CONCLUSIONS

Clinical trial data indicate that high dosages of any NSAID along with any dosage of indomethacin, meclofenamate, or piroxicam increase the risk of dyspepsia by about 3-fold. Other NSAIDs at lower dosages were not associated with an increased risk of dyspepsia.

Do NSAIDs cause dyspepsia? A meta-analysis evaluating alternative dyspepsia definitions

OBJECTIVE

Nonsteroidal anti-inflammatory drugs (NSAIDs) may be associated with dyspepsia, but the relationship is obscured by variations in the terminology used to report GI symptoms. Using alternative definitions, we assessed the relationship between NSAID use and dyspepsia.

METHODS

We searched MEDLINE, EMBASE, HEALTHSTAR, and BIOSIS databases (1966-1997) and New Drug Application reviews, identifying randomized, placebo-controlled trials (5 days or more duration) of any NSAID, reporting original data on GI complications. Based upon reported terms describing upper GI symptoms, we derived three definitions: strict, using terms synonymous with epigastric pain/discomfort; loose, (containing the strict definition plus terms for heartburn, nausea, bloating, anorexia, and vomiting); and a loose definition without heartburn terms (the loose-less-heartburn definition). Using each definition, we performed a random-effects model meta-analysis of the relationship between NSAID exposure and dyspepsia.

RESULTS

Fifty-five published and 37 unpublished controlled NSAID trials met our inclusion criteria. The mean duration of the trials was 33.2 days (SD 40 days). Application of the strict definition resulted in a pooled risk ratio of dyspepsia for NSAIDs compared with placebo of 1.36 (95% CI = 1.11-1.67). For the loose definition, the pooled risk ratio was 1.13 (95% CI = 0.98-1.32). The loose-less-heartburn definition yielded a pooled risk ratio of 1.19 (95% CI = 1.03-1.39). In the placebo-treated control groups, the percent of patients reporting dyspepsia ranged from 2.3% (strict definition) to 4.2% (loose and loose-less-heartburn definitions).

CONCLUSIONS

Using the strict definition, based solely on epigastric pain-related symptoms, NSAIDs increased the risk of dyspepsia by 36% (p < 0.05). These findings may be useful in creating a standardized definition of NSAID-related dyspepsia.

A randomized trial measuring fecal blood loss after treatment with rofecoxib, ibuprofen, or placebo in healthy subjects

PURPOSE

Gastrointestinal microbleeding, as assessed by the measurement of (51)chromium-labeled red blood cells, is a marker of the mucosal injury associated with the use of nonsteroidal anti-inflammatory drugs. This study tested the hypotheses that cyclooxygenase-2 specific inhibition with rofecoxib would cause less fecal blood loss than a therapeutic dose of ibuprofen and would be equivalent to placebo.

SUBJECTS AND METHODS

In this randomized, double-blind group study, gastrointestinal blood loss was assessed by measurement of fecal (51)chromium radioactivity during a 1-week placebo baseline period and during 4 weeks of treatment with rofecoxib (25 mg or 50 mg once daily), ibuprofen (800 mg three times daily), or placebo in 67 healthy subjects. Gastrointestinal blood loss during treatment weeks 2 to 4 (versus the baseline period) was expressed as the geometric mean ratio of fecal radioactivity in weeks 2 to 4 compared with baseline.

RESULTS

Ibuprofen caused significantly (P <0.001) greater gastrointestinal blood loss (geometric mean ratio of 5.2, 95% confidence interval [CI]: 4.2 to 6.3) than the 25-mg dose of rofecoxib (2.6, 95% CI: 2.2 to 3.1), the 50-mg dose of rofecoxib (2.6, 95% CI: 2.2 to 3.0), or placebo (2.1, 95% CI: 1.8 to 2.5). In contrast, gastrointestinal blood loss with both doses of rofecoxib were equivalent to placebo by a predetermined clinical similarity bound.

CONCLUSIONS

In healthy subjects, treatment with rofecoxib, at 2 to 4 times the doses that are currently recommended for the treatment of patients with osteoarthritis, produced significantly less fecal blood loss than a therapeutic dose of ibuprofen and was equivalent to placebo.

Pharmaceutical applications of cyclodextrins. 2. In vivo drug delivery

The objective of this Review is to summarize and critique recent findings and applications of both unmodified and modified cyclodextrins for in vivo drug delivery. This review focuses on the use of cyclodextrins for parenteral, oral, ophthalmic, and nasal drug delivery. Other routes including dermal, rectal, and pulmonary delivery are also briefly addressed. This Review primarily focuses on newer findings concerning cyclodextrin derivatives which are likely to receive regulatory acceptance due to improved aqueous solubility and safety profiles as compared to the unmodified cyclodextrins. Many of the applications reviewed involve the use of hydroxypropyl-beta-cyclodextrins (HP-beta-CDs) and sulfobutylether-beta-cyclodextrins (SBE-beta-CDs) which show promise of greater safety while maintaining the ability to form inclusion complexes. The advantages and limitations of HP-beta-CD, SBE-beta-CD, and other cyclodextrins are addressed.

Effect of piroxicam beta-cyclodextrin complex on experimental inflammation

1. The effectiveness of the inclusion product of piroxicam with beta-cyclodextrin was compared to that of free piroxicam on inflammatory reactions by using three experimental inflammatory models in rats. 2. The inclusion compound showed anti-inflammatory effects similar to those of simple piroxicam on granuloma tissue formation and arthritis induced by complete Freund adjuvant. 3. In carrageenin-induced pleurisy, the piroxicam beta-cyclodextrin reduced leukocyte mobilization more intensely than non-complexed piroxicam. 4. These results suggest that beta-cyclodextrin is a useful tool for improving the efficacy of piroxicam.

Gastroduodenal lesions associated with two different piroxicam formulations. An endoscopic comparison

This endoscopic study was performed to compare the gastroduodenal endoscopic findings after short-term treatment with plain and enteric-coated piroxicam tablets. Sixteen healthy male volunteers (mean age, 22 years; range, 19-27 years) were included in a double-blind, randomized study in which 20 mg piroxicam was given once daily for 2 weeks as plain tablets or enteric-coated tablets in a crossover fashion. The washout period was 5 weeks, and endoscopy was performed before each treatment period to ensure base-line conditions. Endoscopic evaluation of the stomach and duodenum was performed, with separate registration of the duodenum distally to the duodenal bulb. Visual analogue scales of 150 mm were used for grading the mucosal lesions, with separate registration of mucosal injection and erosive and haemorrhagic lesions. A 5-point scale (Lanza scale) was also used, to compare the two scoring systems. A significantly lower lesion score was found with the enteric-coated formulation for all endoscopic variables in both scoring regions. The sum of visual analogue scale scores in the stomach/duodenal bulb after treatment was 121 mm and 74 mm, respectively (p < 0.01), and in the middle and distal duodenum the corresponding figures were 54 mm and 23 mm (p < 0.01). The fixed-point scoring gave identical conclusions, as did the separate scoring by a different investigator evaluating the same endoscopies. Subjective symptoms were similar for the two formulations, and no carryover effects were detected. We conclude that enteric coating of piroxicam tablets may offer a means of protecting the gastroduodenal mucosa in short-term treatment of healthy subjects.

Placebo-controlled comparison of piroxicam-beta-cyclodextrin, piroxicam, and indomethacin on gastric potential difference and mucosal injury in humans

The acute gastroduodenal mucosa injury and gastric potential difference (GPD) drops provoked by 14-day administration of 20 mg/day of a new piroxicam formulation (piroxicam-beta-cyclodextrin), 20 mg/day standard piroxicam and 100 mg/day indomethacin were evaluated and compared in a randomized, double-blind, placebo-controlled study carried out on 64 volunteers. Endoscopic examinations, performed after 14-day treatment, demonstrated that piroxicam-beta-cyclodextrin was less gastrolesive (mean endoscopic score +/- SE = 0.56 +/- 0.2) than either piroxicam (2.06 +/- 0.5) or indomethacin (2.25 +/- 0.5) (p < 0.01). The drop in GPD after a single dose of the assigned drug was considerably greater for piroxicam and indomethacin than for piroxicam-beta-cyclodextrin (p < 0.01), which registered similar values to placebo. Since GPD is an expression of the anatomo-functional integrity of the gastric barrier, the results indicate that piroxicam-beta-cyclodextrin exerts less direct acute damage on the gastric mucosa. Therefore, when administered short-term, piroxicam-beta-cyclodextrin appears to be less gastrolesive than either indomethacin or the standard piroxicam formulation.

Review article: non-steroidal, anti-inflammatory drugs--the extending scope of gastrointestinal side effects

The gastrointestinal side effects of non-steroidal, anti-inflammatory drugs extend beyond the duodenal bulb, and comprise a variety of lesions in all parts of the gut. Gastroduodenal ulceration is quantitatively dominant, although a major part of these lesions probably go unnoticed and heal spontaneously. Adaptation has been demonstrated for acetylsalicylic acid, and may be of importance for other substances as well. Non-steroidal anti-inflammatory drugs (NSAIDs) may induce relapse of inflammatory bowel disease. Permeability changes and mucosal inflammation are found in the small and large bowel in the majority of subjects taking NSAIDs, although the clinical significance is still not clear. Ulceration and perforation do, however, occur in this part of the gut as well. Treatment of NSAID-associated ulceration is similar to traditional ulcer treatment, possibly with extended treatment duration if the NSAID is continued. Prophylaxis is of some value, but is not required for every patient receiving an NSAID.

Gastroduodenal lesions induced by naproxen. An endoscopic evaluation of regional differences and natural course

Gastroduodenal endoscopic findings were studied in 65 healthy volunteers receiving 750 mg or 1000 mg naproxen for 1 or 2 weeks. Separate registration of the mid- and distal duodenum showed that mucosal toxicity can be demonstrated even distally to the duodenal bulb. The lesions were closely correlated to the findings in the stomach and duodenal bulb, though generally somewhat less extensive. Whereas a difference between 750 mg and 1000 mg naproxen was demonstrated in an intraindividual comparison (n = 26; median sum of visual analogue scale score in the stomach/duodenal bulb, 129 mm and 183 mm, respectively; p less than 0.05), no difference was seen in two parallel groups (n = 32 and 33). In the stomach and duodenal bulb, a significant aggravation of mucosal lesions was seen from 1 to 2 weeks in 16 subjects. Healing was complete in 10/12 subjects after 3 weeks, independent of the extent of the initial damage.