Mifepriston ve Toremifen etkileşimi

Drugs known to prolong the QT interval and strong CYP3A4 inhibitors should be avoided [see Warnings and Precautions (5.1) ] .

Coadministration with a strong CYP3A4 inhibitor can result in a relevant increase in FARESTON exposure and should be avoided.

Effect of Strong CYP3A4 Inhibitors on Toremifene In a study of 18 healthy subjects, 80 mg toremifene once daily coadministered with 200 mg of ketoconazole twice daily increased the toremifene Cmax and AUC by 1.4- and 2.9-fold, respectively.

The administration of FARESTON with agents that are strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, clarithromycin, atazanavir, indinavir, nefazodone, nelfinavir, ritonavir, saquinavir, telithromycin, and voriconazole) increase the steady-state concentration in serum and should be avoided.

If interruption of treatment with FARESTON is not possible, patients who require treatment with a drug that strongly inhibits CYP3A4 should be closely monitored for prolongation of the QT interval [see Boxed Warning and Warnings and Precautions (5.1) ] .

There is little or no experience with high exposure, concomitant dosing with other QT-prolonging drugs, or potassium channel variants resulting in a long QT interval. [See Warnings & Precautions ( 5.6 )] To minimize risk, the lowest effective dose should always be used.