Effect of naproxen on gastric acid secretion and gastric pH.
BACKGROUND
The mechanisms for the non-steroidal anti-inflammatory drug-induced inflammation in the stomach are unclear.


OBJECTIVE
To determine if naproxen (Naprosyn, Roche, Nutley, NJ, USA) alters basal acid output, pentagastrin-stimulated maximal acid output, or fasting gastrin.


METHODS
Basal acid output and maximal acid output gastric aspirations were performed pre-naproxen and 7 days post-naproxen 500 mg b.d. in 24 healthy subjects. Volume, pH and acid mEq were determined. Fasting gastrin was obtained. Comparisons were made using paired t-tests (alpha = 0.05).


RESULTS
Dosing with naproxen did not statistically decrease mean pH of the basal acid output gastric fluid (3.3 vs. 3.1; N.S.) or the pentagastrin-stimulated maximal acid output gastric fluid (2.7 vs. 2.6; N.S.). Basal acid output total volume was significantly decreased post-naproxen (84 vs. 61 mL/h; P = 0.01), with no change in maximal acid output total volume (196 vs. 188 mL/h; N.S.). Basal acid output mean gastric acidity was significantly increased post-naproxen (0.04 vs. 0.05 mEq/mL; P = 0.03), with no change in maximal acid output mean gastric acidity after naproxen (0.10 vs. 0.10; N.S.). Gastrin was not altered by dosing with naproxen.


CONCLUSIONS
Naproxen does not influence total acid secreted but does decrease basal gastric fluid volume, thereby increasing basal gastric acid concentration. These observations define one mechanism by which non-steroidal anti-inflammatory drugs may induce gastric injury.
Rodriguez-Stanley
S
S
Oklahoma Foundation for Digestive Research, Oklahoma City, OK, USA. sheila-stanley@ouhsc.edu
Redinger
N
N
Miner
P B
PB
D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D005260:Female; D005744:Gastric Acid / Q000378:metabolism*; D005755:Gastrins / Q000187:drug effects; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D008297:Male; D009288:Naproxen / Q000494:pharmacology*
D000894:Anti-Inflammatory Agents, Non-Steroidal; D005755:Gastrins; D009288:Naproxen