EFFECT OF STANDARD AND HIGH-DOSE RANITIDINE ON [C-13]UREA BREATH TEST-RESULTS

Objective: It has been suggested that standard dose H2 blockers will a ffect the [(14)-C]urea breath test. The aim of this study was to evalu ate the effect of standard and high dose ranitidine on the [C-13]urea breath test in a prospective cross-over study. Methods: Volunteers fou nd to be positive for H, pylori by IgG serology and [C-13]urea breath test were given either ranitidine 150 mg b.i.d. or 300 mg b.i.d. for 1 4 days. Repeat breath tests were completed on the last day of antisecr etory dosing and study patients were immediately crossed over to the o ther ranitidine dose. The third breath test was performed at 14 days a fter initiation of the new dose, Results: A total of 20 volunteers wer e enrolled. Using the established cut-off of 2.4% for the commercial b reath test, only one patient developed negative results on H2 blockers . This patient had negative breath tests on both ranitidine doses and remained test-negative off all medications 6 wk after study completion , suggesting either a false positive baseline test or an unexpected ba cterial eradication, No specific trend in breath test results was obse rved for the group (p = NS), On ranitidine 300 mg, six of 19 patients elevated their breath results from 23% to 112% (mean 76%) above baseli ne. Conclusion: Ranitidine at standard or high doses did not generate a reproducible decline in breath test results, Histamine 2 blockers do not need to be discontinued before urea breath testing. (Am J Gastroe nterol 1998;93:1297-1299. (C) 1998 by Am. Coll. of Gastroenterology).