Quinupristin/Dalfopristin Cyclosporine

Ballow C, Chevalier P, Geary W, Pasquier 0, Forrest A, Montay G, Rey J. Randomized, crossover, phase I study of the interaction between quinupristin/dalfopristin (I 59500) at steady state and cyclosporine in healthy volunteers. Nordic I arma UK, data on file (Ref-Syn-0188). 

Stamatakis MK, Richards JG. Interaction between quinupristin/dalfopristin and cyclosporine. Ann Pharmacother( 99T) 31,576-8. 

Patients with hepatic insufficiency may not tolerate the drug at usual doses, however, because of increased area under the concentration curve of both parent drugs and metabolites. This may necessitate a dose reduction to 7.5 mg/kg every 12 hours or 5 mg/kg every 8 hours in some patients. Quinupristin and dalfopristin are not metabolized by cytochrome P450 enzymes but significantly inhibit CYP 3 A4, which metabolizes warfarin, diazepam, astemizole, terfenadine, cisapride, nonnucleo- side reverse transcriptase inhibitors, and cyclosporine, among others. Dosage reduction of cyclosporine may be necessary. 

---