How often does metronidazole induce pancreatitis?

Two case reports of metronidazole-induced pancreatitis raised the question of how often this reaction occurs. Of 6485 patients who received 7704 computer-recorded prescriptions for metronidazole from a health maintenance organization, none were hospitalized for pancreatitis while taking the drug or within the following month. Accordingly, the upper 95% confidence limit for the occurrence rate of metronidazole-induced pancreatitis requiring hospitalization is 3.9/10,000 prescriptions and 4.6/10,000 recipients; the true rates are probably lower. Severe pancreatitis appears to be a rare adverse reaction to metronidazole.