The newest class of anti-infectives contains drugs that are used against resistant strains of bacteria. The first group of drugs in this class are the Streptogramins which were introduced in 1999.¹ There are two drugs in this group, quinupristin and dalfopristin. They have a synergistic effect and are sold in the United States as a combined drug called Synercid. Quinupristin/dalfopristin (Synercid) is bactericidal and is used to treat infections caused by methicillin-resistant and vancomycin-resistant bacteria as well as Staphylococcus aureus and epidermides. This drug must be used very discriminately so that other new resistant strains of bacteria don’t develop. Quinupristin/dalfopristin (Synercid) is given intravenously. It is well distributed to the skin and soft tissues and excreted through bile via feces.

The Oxazolidinones were introduced in 2000 when the first and only member of the group, linezolid (Zyvox), was approved for use in the United States. Linezolid (Zyvox) is a synthetic drug that was developed to treat serious infections caused by methicillin-resistant and vancomycin-resistant bacteria. It is bactericidal when used against anaerobic, gram-positive, and gram-negative bacteria. This drug must be used cautiously, and numerous health care facilities require their Infectious Disease Committee to approve its use.² Linezolid (Zyvox) can be given orally and intravenously. It is distributed all over the body after quick absorption from the gastrointentinal tract and is excreted via the urine.