Antimicrobial Use Guidelines (AMUG) version 21 - UW Health

4. Life-threatening Gram-negative infections due to organisms such as Acinetobacter species known or likely to beresistant to third-generation cephalosporins (e.g., P aeruginosa, Enterobacter, Serratia or Citrobacter) or in patientsvulnerable to nephrotoxicity with aminoglycosides.5. Neutropenic fever (dose as 500 mg IV Q6H).CommentsAll doses except the first dose are given as prolonged infusion. The first dose is given over 30 minutes to rapidly achievetherapeutic concentrations. Excusion criteria: patients receiving CVVH and patients treated for meningitis. Cystic fibrosispatients may receive prolonged infusion, but are not limited to lower doses specified in the prolonged infusion guideline.Dose adjustment required for renal impairment. See renal dosing guideline on uconnect.For use in patients with reported penicillin allergies, see Appendix J: UWHC Guidelines For the Use of Beta-LactamAntibiotics in Patients with Reported Allergies to Penicillin.METRONIDAZOLEUsual DoseAdult: 500 mg Q8H IV OR 1 g Q12H IV (UWHC cost/day $3.31-4.41) OR 250-750 mg TID PO OR 250 mg four timesdaily PO (colitis) (UWHC cost/day $0.36-1.08).Pediatrics:** 15-35 mg/kg/day PO in divided doses Q8H OR 30 mg/kg/day IV in divided doses Q6H.Indications1.Intra-abdominal abscesses where anaerobes are likely to be pathogens. Usually given with an aminoglycoside or otherantibiotic with Gram-negative activity.2. Bacterial vaginosis.3. Trichomonal vaginitis.4. Giardiasis (250 mg TID PO x 5 days).5. Clostridium difficile colitis (usually oral only; IV is less effective for C difficile colitis, although IV is used with POvancomycin in initial, severe, complicated cases).6. Prophylaxis for colorectal surgery (see Appendix B).7. Brain abscess or anaerobic meningitis (usually given with beta-lactam antibiotics).8. Amebic dysentery and other Entamoeba histolytica infections (especially liver abscesses).9. Treatment of H pylori infection as part of combination regimens.CommentsThe manufacturer recommends a loading dose of 15 mg/kg IV, although this is rarely, if ever, used. Disulfiram-likereactions have been reported. Patients should be counseled regarding alcohol use while taking metronidazole. (NOTE:Many agents contain alcohol as a vehicle.) Metronidazole has limited activity against Gram-positive anaerobic cocci; ithas essentially no activity against aerobic bacteria and no activity against anaerobic Gram-positive rods other thanClostridium (e.g., Actinomyces and Propionibacterium). This usually limits its use to anaerobic infections below thediaphragm. It is not usually necessary to combine metronidazole with ampicillin/sulbactam orpiperacillin/tazobactam as these drugs have adequate anaerobic coverage for most situations. An exception tothis would be a case where C. difficile is suspected or an undrained intra-abdominal abscess. Avoid in firsttrimester of pregnancy. Safety and efficacy in children have not been established except for amebiasis. Metronidazole isused as a second-line drug for giardiasis in children. See IV-to-PO conversion policy (Appendix F) on uconnect. The oralformulation is preferred for treating C. difficile. The 2010 IDSA Guidelines for the treatment of C. difficile recommend adose of 500 mg Q8H PO for the initial and first recurrence of mild-to-moderate C. difficile.Drug InteractionsMetronidazole in combination with warfarin causes increased anticoagulation.