Mifepristone and Vfend

In the database of official manuals used in the service creation an interaction registered by statistical results of studies was found, which can either lead to negative consequences for the patient health or strengthen a mutual positive effect. A doctor should be consulted to address the issue of joint drug administration.

Talk to your doctor before using miFEPRIStone together with voriconazole. Combining these medications may significantly increase the blood levels and effects of miFEPRIStone. This may increase the risk and/or severity of side effects, particularly if you are on this medication for a prolonged period. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

GENERALLY AVOID: Mifepristone may prolong the QTc interval in a dose-related manner. Theoretically, coadministration with other agents that can prolong the QT interval may result in additive effects and increased risk of ventricular arrhythmias including torsade de pointes and sudden death. Mifepristone and its metabolites have been found to inhibit the hERG-encoded cardiac potassium channels responsible for the rapid delayed rectifier K+ (IKr) repolarizing current. However, 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. In general, the risk of an individual agent or a combination of agents causing ventricular arrhythmia in association with QT prolongation is largely unpredictable but may be increased by certain underlying risk factors such as congenital long QT syndrome, cardiac disease, and electrolyte disturbances (e.g., hypokalemia, hypomagnesemia). Since mifepristone can commonly cause hypokalemia during prolonged use, this should also be considered during coadministration with other QT-prolonging drugs. In a study of patients with Cushing's syndrome, hypokalemia was observed in 44% of subjects treated with mifepristone. The hypokalemia responded to treatment with potassium supplementation and/or mineralocorticoid antagonist therapy (e.g., spironolactone or eplerenone).

ADJUST DOSE: Coadministration with potent inhibitors of CYP450 3A4 such as ceritinib, clarithromycin, ketoconazole, posaconazole, saquinavir, telithromycin, and voriconazole may significantly increase the plasma concentrations of mifepristone, which is primarily metabolized by the isoenzyme. The clinical impact of this interaction has not been studied. Additionally, these agents may prolong the QT interval, which may potentiate the risk of cardiac arrhythmias when administered with mifepristone.

MANAGEMENT: When mifepristone is used daily to control hyperglycemia secondary to hypercortisolism in patients with endogenous Cushing's syndrome, coadministration with other drugs that can prolong the QT interval should generally be avoided. If concomitant use with ceritinib, clarithromycin, ketoconazole, posaconazole, saquinavir, telithromycin, or voriconazole is required and no alternatives are available, the dosage of mifepristone should be limited to 300 mg/day in accordance with labeling recommendation for use in combination with potent CYP450 3A4 inhibitors. Serum potassium should be assessed prior to starting mifepristone and 1 to 2 weeks following initiation of therapy or an increase in dosage, and periodically as needed. Hypokalemia must be corrected prior to initiation of mifepristone. Patients should be advised to seek medical attention if they experience potential signs and symptoms of hypokalemia such as fatigue, weakness, myalgia, muscle cramps, numbness, tingling, abdominal pain, constipation, palpitation, and irregular heart rhythm. Because mifepristone is eliminated slowly from the body, drug interactions may be observed for a prolonged period following discontinuation (approximately 2 to 3 weeks if mifepristone had been administered chronically to steady state).

Mifepristone

Generic Name: mifepristone

Brand name: Korlym, Mifeprex

Synonyms: n.a.

What is Mifepristone?

Vfend

Generic Name: voriconazole

Brand name: Vfend, Vfend

Synonyms: Vfend Injection

What is Vfend?