Quinupristin and dalfopristin are intravenously administered, streptogramin antibiotics used in fixed combination to treat severe bacterial infections due to susceptible organisms including methicillin resistant Staphylococcus aureus (MRSA). The fixed combination of quinupristin and dalfopristin is associated with a low rate of serum enzyme elevations during therapy but has not been convincingly linked to instances of clinically apparent liver injury.