Non-steroidal anti-inflammatory drugs (
NSAIDs) can cause dyspeptic symptoms, including
abdominal pain. Gastric mucus is important as the first line of defense against
luminal irritants. In the present study, we investigated whether gastric mucus secretion could influence the severity of gastric mucosal
injuries or
NSAID-induced dyspeptic symptoms. Fifteen Helicobacter pylori-negative, healthy males were administered two types of
NSAIDs, a non-selective
cyclooxygenase inhibitor,
naproxen (300 mg, twice a day), or a cyclooxygenase-2-selective inhibitor,
etodolac (200 mg, twice a day), for 1 week in a crossover study, with an interval of ≥ 4 weeks. Study participants underwent endoscopic examinations before and
after treatment.
Pentagastrin-stimulated gastric secretions were collected for 10 min during endoscopic examinations, and were analyzed for gastric acid levels (mEq/10 min) and mucus output (mg
hexose/10 min). The grade of gastric mucosal injury was assessed endoscopically. Among 29 subjects who completed the crossover study, 11 individuals reported
abdominal pain following the administration of
naproxen or
etodolac for 1 week, as judged by elevated
pain scores, while 18 individuals did not report
abdominal pain. The occurrence of symptoms was not associated with the type of
NSAIDs administered or the occurrence of erosive injury visualized by endoscopy. Gastric mucus secretion was significantly increased in subjects without drug-induced
abdominal pain (P < 0.05), whereas it was significantly reduced in those with drug-induced
abdominal pain (P < 0.05). In conclusion, the occurrence of
NSAID-induced
abdominal pain is associated with reduced levels of gastric mucus secretion rather than the occurrence of endoscopic mucosal injury.