Double-blind, placebo-controlled study on effects of diclofenac sodium and indomethacin on postprandial gastric motility in man

Diclofenac and dexamethasone modulate the effect of cannabidiol on the rat colon motility ex vivo

Introduction

Due to the growing interest in the use of cannabinoids in supportive therapies, they are increasingly used together with anti-inflammatory drugs. Cannabinoids inhibit gastrointestinal motility, while steroidal and nonsteroidal anti-inflammatory drugs influence motility in other ways. The aim of the research was to study the interactions between cannabidiol (CBD) and these two classes of anti-inflammatory drugs in the context of gastrointestinal motility. Dexamethasone (DEX) was selected as a steroidal drug and diclofenac (DCF) as a nonsteroidal counterpart.

Material and Methods

The experiments were performed on isolated rat colon strips in isometric conditions. The contractile response to acetylcholine (ACh) (1 μM) was measured with no substance applied as a control value and was measured after application of CBD (80 μM), DEX (100 μM), DCF (100 μM), or a combination of these substances.

Results

Cannabidiol strongly inhibited intestinal motility mediated by ACh application, DCF inhibited it non-significantly, while DEX intensified it. When CBD was co-administered with DEX, the combination inhibited intestinal motility non-significantly relative to the ACh-only control. Co-administration of CBD with DCF inhibited motility more than when these substances were administered separately.

Conclusion

Inhibition of the intestinal response to ACh is likely due to the synergistic effect of CBD and endogenous cannabinoids. Dexamethasone lessened the inhibitory effect of CBD, likely because of diminished availability of the arachidonic acid necessary for endogenous cannabinoid synthesis. However, diclofenac may increase endogenous cannabinoid synthesis, because of the greater availability of arachidonic acid caused by DCF blocking the cyclooxygenation pathway.

Serotonergic and non-serotonergic targets in the pharmacotherapy of visceral hypersensitivity

Visceral hypersensitivity is considered a key mechanism in the pathogenesis of functional gastrointestinal (GI) disorders. Targeting visceral hypersensitivity seems an attractive approach to the development of drugs for functional GI disorders. This review summarizes current knowledge on targets for the treatment of visceral hypersensitivity, and the status of current and future drug and probiotic treatment development, and the role of pharmacogenomic factors.

Loss of interstitial cells of Cajal network in severe idiopathic gastroparesis

AIM: To report a case of severe idiopathic gastroparesis in complete absence of Kit-positive gastric interstitial cells of Cajal (ICC).

METHODS: Gastric tissue from a patient with severe idiopathic gastroparesis unresponsive to medical treatment and requiring surgery was analyzed by conventional histology and immunohistochemistry.

RESULTS: Gastric pacemaker cells expressing Kit receptor had completely disappeared while the local level of stem cell factor, the essential ligand for its development and maintenance, was increased. No signs of cell death were observed in the pacemaker region.

CONCLUSION: These results are consistent with the hypothesis that a lack of Kit expression may lead to impaired functioning of ICC. Total gastrectomy proves to be curative.

Time dependent risk of gastrointestinal complications induced by non-steroidal anti-inflammatory drug use: a consensus statement using a meta-analytic approach

OBJECTIVES

To provide an updated document assessing the global, NSAID-specific, and time dependent risk of gastrointestinal (GI) complications through meta-analyses of high quality studies.

METHODS

An exhaustive systematic search was performed. Inclusion criteria were: RCT or controlled study, duration of 5 days at least, inactive control, assessment of minor or major NSAID adverse effects, publication range January 1985 to January 2003. The publications retrieved were assessed during a specifically dedicated WHO meeting including leading experts in all related fields. Statistics were performed conservatively. Meta-regression was performed by regressing NSAID adjusted estimates against study duration categories.

RESULTS

Among RCT data, indolic derivates provided a significantly higher risk of GI complications related to NSAID use than for non-users: RR = 2.25 (1.00; 5.08) than did other compounds: naproxen: RR = 1.83 (1.25; 2.68); diclofenac: RR = 1.73 (1.21; 2.46); piroxicam: RR = 1.66 (1.14; 2.44); tenoxicam: RR = 1.43 (0.40; 5.14); meloxicam: RR = 1.24 (0.98; 1.56), and ibuprofen: RR = 1.19 (0.93; 1.54). Indometacin users had a maximum relative risk for complication at 14 days. The other compounds presented a better profile, with a maximum risk at 50 days. Significant additional risk factors included age, dose, and underlying disease. The controlled cohort studies provided higher estimates: RR = 2.22 (1.7; 2.9). Publication bias testing was significant, towards a selective publication of deleterious effects of NSAIDs from small sized studies.

CONCLUSION

This meta-analysis characterised the "compound" and "time" aspects of the GI toxicity of non-selective NSAIDs. The risk/benefit ratio of such compounds should thus be carefully and individually evaluated at the start of long term treatment.

Gastrointestinal side-effects of traditional non-steroidal anti-inflammatory drugs and new formulations

Although adverse effects of non-steroidal anti-inflammatory drugs (NSAIDs) occur in only a small proportion of users, the widespread use of these drugs has resulted in a substantial overall number of affected persons who experience serious gastrointestinal complications. Dyspeptic symptoms are estimated to occur in 10-60% of NSAID users and lead to discontinuation of treatment in 5-15% of rheumatoid arthritis patients taking NSAIDs. It is now well established that the point prevalence of peptic ulcer disease in patients receiving conventional NSAID therapy ranges between 10 and 30%, representing a 10-30-fold increase over that found in the general population. One of 175 users of conventional NSAIDs in the USA will be hospitalized each year for NSAID-induced gastrointestinal damage. The mortality of hospitalized patients remains about 5-10%, with an expected annual death rate of 0.08%. The selective COX-II inhibitors (rofecoxib, celecoxib, parecoxib, etoricoxib, valdecoxib, lumiracoxib) show consistently comparable efficacy to that of conventional non-steroidal anti-inflammatory drugs (NSAIDs) in patients with rheumatoid arthritis and osteoarthritis, but have a significantly reduced propensity to cause gastrointestinal toxicity. In many cases, the gastric effects of therapeutically active doses of COX-II inhibitors are indistinguishable from placebo. The safety benefits of COX-2 inhibitors given alone appear similar to combined therapy with conventional NSAIDs and gastroprotective agents. These findings warrant the consideration of COX-II inhibitors as first-line therapy in patients requiring long-term pain control.

Decreased gastric tone and delayed gastric emptying precede neutrophil infiltration and mucosal lesion formation in indomethacin-induced gastric damage in rats

Gastric antral dysmotility has been implicated in the pathogenesis of indomethacin-induced gastric damage, but the relationship between gastric motor abnormalities and mucosal lesions has not been extensively studied. We investigated whether changes in gastric tone and gastric retention correlate with mucosal lesions and neutrophil migration in indomethacin-induced gastric damage in rats. Indomethacin, either 5 or 20 mg/kg (INDO-5 and INDO-20), was instilled into the stomach, and then gastric damage, neutrophil migration, gastric tone and gastric retention were assessed 1 or 3 h later. Gastric damage was calculated as the sum of the lengths of all mucosal lesions, and neutrophil migration was measured by assaying myeloperoxidase activity. Gastric tone was determined by a plethysmometric method, and gastric retention of either saline or Sustacal was evaluated by a scintigraphic method. Gastric damage was detectable 3 h after either INDO-5 or INDO-20, but not after 1 h. Neutrophil migration was significantly higher 3 h after INDO-20 as compared with INDO-5 or control group, but not after 1 h. Values of gastric tone 1 and 3 h after either INDO-5 (1 h = 1.73+/-0.07 ml; 3 h = 1.87+/-0.03 ml) or INDO-20 (1 h = 1.70+/-0.02 ml; 3 h = 1.79+/-0.03 ml) were significantly lower than in controls (1 h = 1.48+/-0.05 ml; 3 h = 1.60+/-0.06 ml). Gastric retention of saline was higher 1 h after INDO-5 (58.9+/-3.3%) or INDO-20 (56.1+/-3.1%) compared to control (45.5+/-1.7%), but not after 3 h. There were no differences concerning gastric retention of Sustacal between the various groups. Indomethacin induced decreased gastric tone and delayed gastric emptying, which precede mucosal lesion and neutrophil infiltration. These results indicate that there is no relationship between these gastric motor abnormalities and mucosal lesion in indomethacin-induced gastropathy.

Nonsteroidal anti-inflammatory drug gastropathy

By inhibiting prostaglandin synthesis, nonsteroidal anti-inflammatory drugs (NSAIDs) compromise gastroduodenal defense mechanism including blood flow and mucus/bicarbonate secretion. This has led to NSAIDs being the most widely reported drug cause of adverse events. While NSAIDs also cause dyspepsia, inhibition of prostaglandin synthesis may reduce this from even higher levels that would otherwise prevail and mask ulcer-related dyspepsia, making anticipatory management difficult. On average, the risk of ulcer complications increases 4-fold, resulting in 1.25 additional hospitalizations per 100 patient-years according to one estimate. Older patients, those with a past history, and those taking anticoagulants or corticosteroids are at higher risk. Risk is dose dependent and is lower with ibuprofen at low doses than with other NSAIDs. It is unlikely that Helicobacter pylori increases the risk, and under some circumstances it may be protective. Selective inhibitors of the inducible cyclooxygenase 2 spare gastric mucosal prostaglandin synthesis and do not damage the gastric mucosa. Their place in therapy, compared with use of misoprostol or proton pump inhibitors, is currently emerging. Future competitors may include nitric oxide-donating, zwitterionic, or R-enantiomer NSAIDs.

Gastroduodenal motility

Several major themes emerged over the past year in the area of gastroduodenal motility. Mostly, these themes represented extensions of research areas discussed in prior reviews in this series rather than the emergence of completely new concepts. Thus, for example, considerable emphasis has again been placed on regional gastric motor function in dyspepsia and on the role of fundic relaxation and accommodation, in particular. Not surprisingly, basic physiologic research has also shown a keen interest in the regulation of fundic relaxation. One new and exciting development is the recognition of the stomach's role in satiety. The spectrum of gastric motor dysfunction in diabetes mellitus continues to be explored, and the important role of hyperglycemia in regulating gastric function has been further emphasized. More data have been provided on noninvasive alternatives to gastric motor function testing, and several studies have looked at factors that may influence variability in these various tests. There have been few innovations over the past year in the therapeutic arena; rather, the indications and limitations of current therapies have been further developed.