QUINUPRISTIN/DALFOPRISTIN

By Dr. Ahmad Najmi, Index Medical College, Indore
Quinupristin/dalfopristin is a combination of quinupristin, a streptogramin B, with dalfopristin, a streptogramin A, in a 30:70 ratio
These compounds are semisynthetic derivatives of naturally occurring pristinamycins, produced by Streptomyces pristinaespiralis
Quinupristin/dalfopristin is active against gram-positive cocci, including S. pneumoniae, beta- and alpha-hemolytic strains of streptococci, E. faecium (but not E. faecalis), and coagulase-positive and coagulase-negative strains of staphylococci
Quinupristin and dalfopristin are protein synthesis inhibitors that bind the 50S ribosomal subunit
The combination of quinupristin/dalfopristin is administered only by intravenous infusion over at least 1 hour. It is incompatible with saline and heparin and should be dissolved in 5% dextrose in water
Quinupristin/dalfopristin is approved in the United States for treatment of infections caused by vancomycin-resistant strains of E. faecium and complicated skin and skin-structure infections caused by methicillin-susceptible strains of S. aureus or S. pyogenes
Quinupristin/dalfopristin should be reserved for treatment of serious infections caused by multiple-drug-resistant gram-positive organisms such as vancomycin-resistant E. faecium
The most common side effects are infusion-related events, such as pain and phlebitis at the infusion site and arthralgias and myalgias
Quinupristin/dalfopristin inhibits CYP3A4
(Reference Goodman & Gillmans, The Pharmacological Basis of Therapeutics, 11th edition)