Evaluation of doripenem utilization and susceptibilities at a large urban hospital

Background Bacterial resistance presents a constant challenge in the treatment of hospitalized patients, particularly with Gram-negative infections. Carbapenems have an important role in the treatment of resistant nosocomial organisms. Doripenem, a recently approved carbapenem, has shown efficacy in clinical trials, but there is little published data on utilization in a general patient population. Objective The clinical utilization of doripenem in a general adult inpatient population was evaluated during a carbapenem formulary conversion. Setting A 706-bed acute care tertiary hospital serving an urban community. Methods After formulary conversion to doripenem, the first 100 patients to receive doripenem were included in the analysis. Baseline characteristics were recorded for each patient, along with indication for treatment, prescribing physician, dose and frequency of doripenem and duration of treatment. Patients were monitored for adverse reactions to doripenem. Bacterial culture results were recorded. For positive cultures, doripenem susceptibility was determined by Etest. Patients were followed until discontinuation of antibiotic therapy, discharge or death to determine treatment outcomes. Successful treatment was defined as clinical or microbiological cure, while patients with infection-related mortality or requiring subsequent antibiotics for the index infection were considered treatment failure. Main outcome measures Clinical utilization of doripenem, including indications and doses used. Results Doripenem treatment was recorded in 102 patients. The most common indications for treatment were pneumonia and sepsis. The majority of doripenem orders were written by Infectious Disease or Pulmonology Services. Forty-nine patients were treated successfully with doripenem and six patients experienced treatment failure. The remainder of patients were not evaluable by predefined outcomes criteria. Adverse events were reported in eight patients and included acute renal failure, Clostridium difficile-associated diarrhea and seizures. Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa were the most common organisms in culture results. Doripenem demonstrated in vitro activity against 81% of all organisms and susceptibility results had >90% correlation with meropenem and imipenem susceptibilities. Conclusion In our limited sample size, doripenem was safe and effective against various types of infections in a general inpatient population with similar bacterial susceptibilities to other cabapenems. Doripenem was utilized for appropriate indications, but doses were frequently outside the manufacturers labeling. Adverse events were uncommon, and no serious adverse events were directly associated with doripenem treatment.