The Relationship Between the Content of Aggressive and Protective Components in Gastric Juice and Endoscopic Findings After Naproxen Sodium and Acetaminophen Administration

Objectives: To evaluate the diagnostic value of residual gastric juice, we assessed various secretory components before and after placebo, acetaminophen, or naproxen sodium administration.

Methods: In a double-blind, randomized, cross-over study in 30 asymptomatic volunteers, mucin, hydrophobicity, protein, pepsin, and pH were measured in residual gastric juice before and after placebo, naproxen sodium (660 mg/d), or acetaminophen (4000 mg/d) administration. Mucus layer thickness in biopsy specimens was assessed, and mucosal damage was endoscopically evaluated.

Results: All parameters were unchanged after 7 days of placebo. Naproxen caused a 46% (p = 0.008) increase in the rate of luminal mucin release, an 18% increase (p = 0.510) in protein release, and a 61% decrease (p = 0.001) in hydrophobicity. Antral and duodenal mucus gel thickness were compromised, and hemorrhagic and erosive endoscopic changes were noted. Acetaminophen resulted only in a significant decline of pepsin. In subjects without endoscopic damage after naproxen, a nonsignificant decrease in hydrophobicity was noted. However, in subjects with endoscopic changes, a 55% decrease (p = 0.002) in hydrophobicity and a 42% increase (p = 0.024) in the rate of luminal mucin release were demonstrated. The initial mucin of subjects who developed endoscopic mucosal changes after naproxen was 53% higher than in subjects without damage. Subjects with endoscopic changes also exhibited a 48% lower initial hydrophobicity and a 43% lower pepsin than subjects without endoscopic changes.

Conclusions: Gastric mucosal damage after naproxen sodium results in profound changes within the gastric mucosal barrier, and analysis of residual gastric juice components adequately reflects these changes. In contrast, acetaminophen results in only minimal gastric juice changes. Analysis of residual gastric juice may be useful in monitoring the extent of mucosal damage and identifying patients likely to develop mucosal damage.