The treatment of resistant pathogens is becoming more difficult, and only a few novel antimicrobial agents are currently in development with activity against highly resistant Gram negative bacteria. Doripenem is a carbapenem antibacterial agent with a broad spectrum of activity against Gram-negative and Gram-positive bacteria. This agent is often used as the last line of therapy for highly resistant Gram negative bacilli nosocomial pathogens. In common with other beta-lactam, the main pharmacokinetic/pharmacodynamic (PK/PD) index that correlates with the therapeutic efficacy is the time that concentrations in the tissue and serum are above the MIC (t>MIC). However, in tropical countries the stability of carbapenem antibiotics is an important consideration when considering continuous infusion. Therefore, prolonged infusion may be a useful route of administration to maximize bactericidal activity. In addition, pharmacokinetic changes have been found for several antimicrobial agents in critically ill patients, including ventilator-associated pneumonia. However, until now we have had no data to reveal the PK/PD index of doripenem in these critically ill patients.