Biliary excretion of radiochromium

Time course and pattern of blood loss with ibuprofen treatment in healthy subjects

BACKGROUND & AIMS

Nonselective nonsteroidal anti-inflammatory drug (NSAID) users are at increased risk of gastrointestinal bleeding. We aimed to assess the pattern and extent of fecal blood loss (FBL) with ibuprofen, which is considered to have a favorable gastrointestinal safety profile.

METHODS

We conducted a post hoc analysis of 2 separate randomized, parallel-group, double-blind studies, in which ibuprofen was used as a positive control. FBL was measured by radioactive analysis of chromium-51 labeled red cells in stools during baseline and then followed by 4 weeks of treatment with ibuprofen (800 mg 3 times daily) or placebo in 68 healthy volunteers. FBL was considered significant when blood loss was >2 mL daily.

RESULTS

The baseline period was identical for all subjects, with an average FBL of 0.36 mL (standard deviation, +/-0.075) per day. During the study period, all subjects receiving ibuprofen had a daily mean FBL >2 mL, with a group daily mean loss 3.64-fold greater than in the placebo group (2.55 mL [+/-3.2] vs 0.7 mL [+/-0.37], P < .001). In the ibuprofen group (n = 31), 26 subjects had between 1 and 7 random episodes of microbleeding with FBL >3 mL. Nine had a maximum FBL >10 mL (29.35 +/- 23.32 mL), and in 2 subjects blood loss reached 73 mL and 66 mL, respectively.

CONCLUSIONS

Treatment with a therapeutic dose of ibuprofen, a commonly used nonselective NSAID, in healthy subjects is associated with significant FBL, which occurs randomly with spikes of bleeding, sometimes exceeding 66 mL in a single day. Chronic anemia or gastrointestinal bleeding in patients taking nonselective NSAIDs should be thoroughly investigated.

A randomized trial measuring fecal blood loss after treatment with rofecoxib, ibuprofen, or placebo in healthy subjects

PURPOSE

Gastrointestinal microbleeding, as assessed by the measurement of (51)chromium-labeled red blood cells, is a marker of the mucosal injury associated with the use of nonsteroidal anti-inflammatory drugs. This study tested the hypotheses that cyclooxygenase-2 specific inhibition with rofecoxib would cause less fecal blood loss than a therapeutic dose of ibuprofen and would be equivalent to placebo.

SUBJECTS AND METHODS

In this randomized, double-blind group study, gastrointestinal blood loss was assessed by measurement of fecal (51)chromium radioactivity during a 1-week placebo baseline period and during 4 weeks of treatment with rofecoxib (25 mg or 50 mg once daily), ibuprofen (800 mg three times daily), or placebo in 67 healthy subjects. Gastrointestinal blood loss during treatment weeks 2 to 4 (versus the baseline period) was expressed as the geometric mean ratio of fecal radioactivity in weeks 2 to 4 compared with baseline.

RESULTS

Ibuprofen caused significantly (P <0.001) greater gastrointestinal blood loss (geometric mean ratio of 5.2, 95% confidence interval [CI]: 4.2 to 6.3) than the 25-mg dose of rofecoxib (2.6, 95% CI: 2.2 to 3.1), the 50-mg dose of rofecoxib (2.6, 95% CI: 2.2 to 3.0), or placebo (2.1, 95% CI: 1.8 to 2.5). In contrast, gastrointestinal blood loss with both doses of rofecoxib were equivalent to placebo by a predetermined clinical similarity bound.

CONCLUSIONS

In healthy subjects, treatment with rofecoxib, at 2 to 4 times the doses that are currently recommended for the treatment of patients with osteoarthritis, produced significantly less fecal blood loss than a therapeutic dose of ibuprofen and was equivalent to placebo.