danazol and Halfan Interactions

Interactions between danazol and Halfan (halofantrine)

danazol and halofantrine (Major Drug-Drug)

MONITOR CLOSELY: Coadministration with inhibitors of CYP450 3A4 may increase the plasma concentrations of halofantrine, resulting in an increased risk of QT interval prolongation and ventricular arrhythmias. The mechanism is inhibition of CYP450 3A4, the isoenzyme responsible for the metabolic clearance of halofantrine. Halofantrine has been associated with QT interval prolongation, ventricular arrhythmias, and sudden death, even at recommended dosages.

MANAGEMENT: Caution and close monitoring is recommended if halofantrine is prescribed with CYP450 3A4 inhibitors, especially potent inhibitors such as itraconazole, ketoconazole, nefazodone, delavirdine, ketolide and certain macrolide antibiotics, and most protease inhibitors. The manufacturer recommends performing an ECG before initiating halofantrine therapy and cardiac monitoring during and for 8 to 12 hours after completion of therapy.