RESUMO
GOAL: The study was designed to compare the gastrointestinal tolerability of a magnesium hydroxide-containing ibuprofen tablet (buffered ibuprofen) and the conventional ibuprofen tablet in healthy volunteers. BACKGROUND: Magnesium hydroxide has been shown to increase the rate of absorption of ibuprofen. METHODS: A double blind, randomized, 2-period crossover study design was used. Twenty healthy men ingested 800 mg ibuprofen 3 times daily either in conventional tablets (2 doses of 400 mg) or in tablets containing magnesium hydroxide (2 doses of 400 mg ibuprofen and 200 mg magnesium hydroxide). On the 5th day only the morning dose was administered. Endoscopy was performed at baseline and on the 5th day in both treatments 2 hours after the last dose, and gastric pH was determined. In addition, plasma concentrations of ibuprofen were determined up to 90 minutes. RESULTS: The magnesium hydroxide-containing formulation increased the number of subjects evincing erosions in gastric corpus and antrum. In the gastric corpus 2 and 7 volunteers had erosions after conventional and buffered ibuprofen, respectively (P = 0.08). In the gastric antrum 5 and 13 volunteers showed erosions after conventional and buffered ibuprofen, respectively (P = 0.02). There was a trend toward faster absorption of ibuprofen when given together with magnesium hydroxide. The difference was not however statistically significant. CONCLUSIONS: Prolonged use of magnesium hydroxide together with high doses of ibuprofen should be avoided, because the combination may incur a higher risk of gastrointestinal irritation.