Metronidazole Equals Vancomycin in C. Diff. Diarrhea



CHICAGO – Oral metronidazole was just as effective as oral vancomycin in treating Clostridium difficile diarrhea, regardless of the severity of illness, in a single-center study.

There also were no differences in mortality with use of either antibiotic, primary author Dr. Qamar Saleheen reported during a poster session at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.

"Based on these findings, we ask this question to the medical community: ‘Is using one antibiotic over the other justified based upon severity of illness without consideration to the financial impact of using vancomycin, which is much more expensive than metronidazole?’ " the researchers asked in a press statement.

According to guidelines on the treatment of C. difficile diarrhea published in May 2010 by the Society for Healthcare Epidemiology of America, oral metronidazole is recommended for mild to moderate illness while oral vancomycin is recommend for severe illness (Infect. Control Hosp. Epidemiol. 2010;31:431-55).

Between Jan. 1, 2009 and March 31, 2010, Dr. Saleheen and his associates at Edward Hines Jr. VA Hospital in Hines, Ill., reviewed the charts of 147 patients with C. difficile positive stools. A total of 25 patients with a mean age of 67 years initially received oral vancomycin and 122 with a mean age of 68 years initially received oral metronidazole. Of 122 patients initially treated with metronidazole, 28 received crossover treatment with vancomycin.

Dr. Saleheen, an infectious diseases fellow at Loyola University Medical Center, Maywood, Ill., reported that in the vancomycin group, 14 patients (56%) had severe disease, of whom 3 patients (12%) had recurrence. Of the 11 patients (44%) who had nonsevere disease, none had a recurrence.

In the metronidazole group, 59 patients (48%) had severe disease, of whom 16 (13%) had recurrence; of the 63 (52%) with nonsevere disease, 11 (9%) had recurrence.

The researchers found that metronidazole was equivalent to vancomycin regardless of the severity of illness (P = .14). There were also no statistically significant differences between the two groups in the rate of recurrence or complications.

The researchers acknowledged certain limitations of the study, including its retrospective design, its relatively small sample size, and the fact that only two patients were female.

"There is a need for a prospective, head-to-head trial of these two medications, but I’m not sure who’s going to fund that study," Dr. Saleheen said in an interview at the meeting, which was sponsored by the American Society for Microbiology. "There is a paucity of data on this topic so it’s hard to say which antibiotic is better. We’re not jumping to any conclusions. There is no fixed management. We have to individualize each patient and treat accordingly."

The study’s principal investigators were Dr. Joseph R. Lentino and Dr. Constance Pachucki, both of Loyola University Chicago. The study’s fourth investigator was Dr. Mohammed Bilgrami, who is also an infectious diseases fellow at Loyola University Medical Center.

The researchers stated that they had no relevant financial conflicts to disclose.

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