A new carbapenem antibiotic, doripenem (Doribax), was recently approved by the Food and Drug Administration for the treatment of complicated intraabdominal infection and urinary tract infection (UTI), including pyelonephritis in adults. Administered by intermittent iv infusion, it's effective against the following organisms:
* In complicated intraabdominal infections-Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Bacteroides caccae, B. fragilis, B. thetaiotaomicron, B. uniformis, B. vulgatus, Streptococcus intermedius, S. constellatus, and Peptostreptococcus micros
* In complicated UTI-E. coli (including cases involving concurrent bacteremia), K. pneumoniae, Proteus mirabilis, P. aeruginosa, and Acinetobacter baumannii
The product label states that the drug is not approved for administration by inhalation because that route was found to induce pneumonitis. The drug inhibits the biosynthesis of the bacterium's cell wall, thereby weakening it and causing it to break apart. Doripenem was found to be as effective as other carbapenems.
Like other carbapenems and other antibiotics similar to penicillin, doripenem poses the risk of serious, sometimes fatal anaphylaxis, although that was observed rarely in clinical trials. Because of the possibility of hyperreactivity, special caution should be exercised in patients allergic to penicillins or other [beta]-lactam antibiotics. Also, doripenem can cause diarrhea induced by Clostridium difficile, but the risk posed is no greater than that associated with other antibiotics. Another warning pertaining to doripenem is of a significant possible interaction with the antiseizure drug valproic acid (Depakote) that could reduce the serum concentration of the latter to a less than therapeutic level, weakening seizure control. The most common adverse effects of doripenem observed in clinical trials were headache, nausea, diarrhea, rash, and phlebitis.
To minimize the patient's risk of developing bacterial resistance to doripenem, nurses should confirm that the patient is, indeed, infected with an organism that is susceptible to it.