Table I. Treatment Regimens for Complicated UTI (known organism and susceptibility) Organism Antibiotic Dose Alternative ORAL Therapy E. coli Ampicillin-clavulanate 875 Klebsiella sp Trimethoprim- One DS tablet bid (Oral) mg bid (oral) Proteus sp sulfamethoxazole Cefuroxime axetil (oral) other gram Ciprofloxacin 500 mg bid or 1000XR 250-500 mg bid negative rod qd (Oral) Cepodoxime proxetil (oral) Levofloxacin 500 – 750 mg qd (Oral) 200 mg bid Nitrofurantion (cystitis 100 mg bid (oral) only) 3 gm sachet (single dose Fosfomycin x 1 or qod) (oral) IV Therapy Ceftriaxone 1 gm bid (IV) Ampicillin/sulbactam 3 gm Ciprofloxacin 400 mg bid (IV) q 6h (IV) Levofloxacin 500 – 750 mg qd (IV) Piperacillin/tazobactam Aminoglycosides* 3.375 mg q 8h (IV) Gentamicin 3-5 mg/kg per day in 2-3 Ticarcillin/clavulanate 3.1 divided doses IV gm q 4-6h (IV) 3-5 mg/kg per day in 2-3 Imipenem-cilastin 500 mg q Tobramycin divided doses IV 8h (IV) 7.5 mg/kg q 12h IV Ertapenem 1 gm qd (IV) Meropenem 500 mg q8h Amikacin (IV) Doripenem 500 mg q8h (IV) Known or Imipenem-cilastin 500 mg q 8h Nitrofurantion 100 mg bid Suspected (oral) (cystitis only) Ertapenem 1 gm qd Extended Fosfomycin 3 gm single dose Spectrum Meropenem 500 mg q 6-8h IV Beta- sachet (oral) every other day for 3 doses (cystitis only lactamase Doripenem 500 mg q8h IV and if no other active agent; (ESBL) not FDA approved for complicated cystitis) OR ceftazidime-avibactam (consider for ESBLs or 2.5 gm q8h IV KPCs) SIRS, awaiting susceptibility results ceftolozane-tazobactam 1.5 gm q q8h IV (consider for ESBLs) Amoxicillin 500 mg every 8h (Oral) Ampicillin-clavulanate 875 mg bid (oral) Ampicillin 1-2 gm q 6h (IV) Ampicillin-sulbactam 1.5 gm q 6h (IV) 15-20 mg/kg/dose every Linezolid 600 mg bid IV or Vancomycin Enterococcus 8-12h (IV) oral (if VRE and no other active agents; not FDA Nitrofurantion (cystitis approved for this indication) 100 mg bid (oral) only) Daptomycin 4 mg/kg q24h IV (if VRE and no other 3 gm sachet (single dose) Fosfomycin active agents; not FDA (oral) approved for this indication) 500 mg bid or 1000XR qd (Oral) Levofloxacin 750 mg (IV or Ciprofloxacin OR Oral qd) 400 mg bid IV Cefepime 2 gm q 12h IV Pseudomonas aeruginosa Ceftazidime 2 gm q 8h IV 3.375 gm q 6h OR 4.5 gm Piperacillin-tazobactam q 8h IV Ticarcillin-clavulanate 3.1 gm q 4h IV Aztreonam 2 gm q 8h IV Aminoglycosides Gentamicin 3-5 mg/kg per day in 2-3 divided doses IV Tobramycin 3-5 mg/kg per day in 2-3 divided doses IV Amikacin 7.5 mg/kg q 12h IV Meropenem 500 mg q 6-8 h IV Imipenem Doripenem 500 mg q8h IV 500 mg q 6h IV ceftazidime-avibactam 2.5 gm q8h IV ceftolozane-tazobactam (consider for multi-drug 1.5 gm q q8h IV resistant Pseudomonas) DS = double-strength; VRE = vancomycin resistant enterococci; * Aminoglycosides can be used alone or in combination (preferred) and should be avoided if the serum creatinine is elevated or obstruction is suspected .