Effect of one-month treatment with nonsteroidal antiinflammatory drugs (NSAIDs) on gastric pH of rheumatoid arthritis patients.

The use of NSAIDs is strongly associated with peptic ulceration. The inhibition of prostaglandin synthesis with the consequent increase of gastric acidity is considered a possible mechanism. Therefore we decided to assess the effect of one-month treatment with NSAIDs on the circadian gastric pH of rheumatoid arthritis (RA) patients. We studied 11 consecutive patients (one man and 10 women, median age 55, range 26-72 years) with confirmed RA. None was H. pylori positive. A 24-hr gastric pH recording was performed both in basal conditions and after one-month treatment with either indomethacin 150 mg/day (eight cases) or ketoprofen 300 mg/day (three cases). Only the 10 female patients were eligible for final analysis, and six matched healthy subjects not taking NSAIDs were used as control group. The number of 24-hr pH readings for various pH thresholds was calculated for both populations. The highest acid levels (pH < 3.0) did not differ between the two pH profiles of the control group (7440 vs 7391, P = NS), while they predominated after the one-month NSAID treatment (10,339 vs 11,440, P < 0.001) in RA patients. These findings show that there is an increased gastric acidity after one-month of treatment with NSAIDs in female patients with RA of recent onset. This may sustain the rationale of using antisecretory agents to prevent gastroduodenal ulcerations in these patients.