Drug Interactions between boceprevir and drospirenone / estradiol

Boceprevir may significantly increase the blood levels of drospirenone. This can increase the risk of developing hyperkalemia, or high levels of potassium in the blood, which in severe cases can lead to kidney failure, muscle paralysis, irregular heart rhythm, and cardiac arrest. Hyperkalemia is usually more likely to occur in people who are dehydrated or have kidney disease, diabetes, or advanced heart failure. Regular or long-term use of nonsteroidal anti-inflammatory drugs such as ibuprofen or naproxen (Aleve), or prescription medications such as potassium supplements or certain medications used to treat high blood pressure or heart conditions, may also increase the risk. Talk to your doctor if you have any questions or concerns. Your doctor may be able to prescribe alternatives that do not interact, or you may need a dose adjustment or more frequent monitoring to safely use both medications. You should seek medical attention if you experience nausea, vomiting, weakness, confusion, tingling of the hands and feet, a weak pulse, or a slow or irregular heartbeat, as these may be symptoms of hyperkalemia. 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.

Consumer information for this interaction is not currently available.

MONITOR: Coadministration with the hepatitis C virus (HCV) NS3/4A protease inhibitors, boceprevir and telaprevir, may decrease the plasma concentrations and efficacy of estrogens used for hormonal replacement therapy. The mechanism involves induction of CYP450 3A4, the isoenzyme primarily responsible for the metabolic clearance of sex hormones. When an oral contraceptive containing drospirenone-ethinyl estradiol (3 mg-0.02 mg daily for 14 days) was given in combination with boceprevir (800 mg three times daily for 7 days), ethinyl estradiol systemic exposure (AUC) decreased by approximately 25%, with no change in the peak plasma concentration (Cmax). In a study of 24 subjects who were administered an oral contraceptive containing ethinyl estradiol-norethindrone (0.035 mg-0.5 mg daily) concomitantly with telaprevir (750 mg every 8 hours) for 21 days, the Cmax and AUC of ethinyl estradiol decreased by 26% and 28%, respectively. In addition, there was a 33% reduction in the trough plasma concentration (Cmin) of ethinyl estradiol.

MANAGEMENT: Dosage adjustments as well as increased clinical and laboratory monitoring for estrogen deficiency should be considered whenever boceprevir or telaprevir is used concomitantly with estrogens used for hormonal replacement therapy.