BACKGROUND: Because of their potent antiviral effects, protease inhibitor (PI)-containing antiretroviral regimens (ARV) have become one of the cornerstones of HIV treatment. Success with their use has however been dampened by increasing emergence of resistant viral gene mutation with consequent treatment failure. Since the availability of newer antiviral agents with activity against resistant viral strains are limited, clinicians are increasingly resorting to ritonavir (RTV) enhanced dual PI therapy to treat salvage patients.