Comparison of the effects of etodolac SR and naproxen on gastro-intestinal blood loss

Pharmacotherapy of scleritis: current paradigms and future directions

INTRODUCTION

Scleritis is an inflammatory condition affecting the eye wall that may be associated with a number of systemic inflammatory diseases. Because scleritis can be refractory to standard treatment, knowledge of the body of available and emerging therapies is paramount and is reviewed here.

AREAS COVERED

This review focuses on both traditional and emerging therapies for noninfectious scleritis. The authors cover the mechanisms of action and potential adverse effects of each of the treatment modalities. In addition, a summary of the significant MEDLINE indexed literature under the subject heading 'scleritis', 'treatment', 'immunomodulator' will be provided on each therapy, including commentary on appropriate use and relative contraindications. Novel treatments and potential drug candidates that are currently being evaluated in clinical trials with therapeutic potential will also be reviewed.

EXPERT OPINION

While oral nonsteroidal anti-inflammatory drugs and oral corticosteroids are widely used, effective, first-line agents for inflammatory scleritis, refractory cases require antimetabolites, T-cell inhibitors, or biologic response modifiers. In particular, there is emerging evidence for the use of targeted biologic response modifiers, and potentially, for local drug delivery.

Cyclooxygenase Isozymes: The Biology of Prostaglandin Synthesis and Inhibition

Nonsteroidal anti-inflammatory drugs (NSAIDs) represent one of the most highly utilized classes of pharmaceutical agents in medicine. All NSAIDs act through inhibiting prostaglandin synthesis, a catalytic activity possessed by two distinct cyclooxygenase (COX) isozymes encoded by separate genes. The discovery of COX-2 launched a new era in NSAID pharmacology, resulting in the synthesis, marketing, and widespread use of COX-2 selective drugs. These pharmaceutical agents have quickly become established as important therapeutic medications with potentially fewer side effects than traditional NSAIDs. Additionally, characterization of the two COX isozymes is allowing the discrimination of the roles each play in physiological processes such as homeostatic maintenance of the gastrointestinal tract, renal function, blood clotting, embryonic implantation, parturition, pain, and fever. Of particular importance has been the investigation of COX-1 and -2 isozymic functions in cancer, dysregulation of inflammation, and Alzheimer's disease. More recently, additional heterogeneity in COX-related proteins has been described, with the finding of variants of COX-1 and COX-2 enzymes. These variants may function in tissue-specific physiological and pathophysiological processes and may represent important new targets for drug therapy.

Effect of clopidogrel on naproxen-induced gastrointestinal blood loss in healthy volunteers

The effect of clopidogrel, a potent inhibitor of platelet aggregation, on naproxen-induced faecal blood loss was investigated in 30 healthy volunteers in a randomized, double-blind, placebo-controlled, two parallel treatment groups study. All subjects first received naproxen 250 mg b.i.d. during 7 days, after which they were randomly allocated to additionally receive either clopidogrel 75 mg once daily (n = 15) or matching placebo (n = 15) for 11 days. Faecal blood loss was measured by the 51Cr-labelled erythrocyte method during the last four days of each of the four study periods, i.e. baseline, treatment with naproxen alone, combined treatment and wash-out. Mean daily faecal blood loss was below 0.5 ml/day during the baseline period in both treatment groups and increased during treatment with naproxen alone to (mean +/- SD) 1.14 +/- 0.58 ml/day in the naproxen + placebo group and to 1.93 +/- 1.51 ml/day in the naproxen + clopidogrel group. Addition of clopidogrel to naproxen treatment was associated with an increase of the mean daily blood loss to 6.83 +/- 9.32 ml/day, which was statistically significantly higher than 1.75 +/- 1.40 ml/day observed during treatment with naproxen + placebo. During the wash-out period, mean daily blood loss decreased to 0.98 +/- 0.51 ml/day in the naproxen + placebo group and to 1.07 +/- 0.46 ml/day in the naproxen + clopidogrel group. Based on these results, it can be concluded that clopidogrel increases naproxen-induced gastrointestinal blood loss in healthy volunteers. Caution should therefore be called for when these drugs are coadministered.

Gastrointestinal blood loss induced by bromfenac sodium, aspirin, and placebo

The effects of bromfenac sodium, aspirin, and placebo on gastrointestinal (GI) blood loss were compared. In a 22-day, randomized study, healthy men received treatment with either bromfenac sodium 300 mg/d, aspirin 3900 mg/d, or placebo for 10 days. On days 3 through 9 and days 20 through 22, all patients received placebo. Fecal blood was measured using the chromium 51-labeled red blood cell technique. Thirty-seven subjects entered the treatment period (13 in the aspirin group, 12 in the bromfenac sodium group, and 12 in the placebo group). The mean change in fecal blood loss during the treatment period compared with the baseline period was significantly greater in the aspirin group (8.00 +/- 4.17 mL/d) than in the bromfenac sodium group (1.63 +/- 1.01 mL/d). Blood loss in both the aspirin and bromfenac sodium groups was significantly greater than in the placebo group (-0.12 +/- 0.25 mL/d). It is concluded that bromfenac sodium 300 mg/d, a higher daily dose than the proposed daily dose, causes significantly less GI blood loss than aspirin 3900 mg/d.

The safety profile of sustained-release etodolac

The safety profile of a new sustained-release (SR) form of etodolac was evaluated in 539 young and elderly patients with osteoarthritis or rheumatoid arthritis. Four long-term, open-label studies were conducted in nine different countries totaling 3,827 patient-months' exposure to etodolac SR. Patients were treated with either 400 mg or 600 mg etodolac SR once a day for up to 52 weeks. Withdrawals due to adverse reactions were low, occurring in only 5% (26/539) of all patients. The most common drug-related study events were GI-related, occurring in < 8% of patients. Elderly persons (> or = 65 years of age) were not at greater risk for adverse reactions or drug-related study events than were younger patients. Serious GI-related study events were rare (0.2%). The low level of serious GI effects was consistent with a separate study measuring gastrointestinal (GI) blood loss. Etodolac SR produced significantly less GI blood loss than naproxen in normal subjects. Because of its favorable safety profile, etodolac SR can serve as an alternative to conventional etodolac, providing the convenience of once-daily administration.