Drug-Drug Interactions Added to Hepatitis C Drug Label


New information about interactions between boceprevir and several other drugs has been added to the prescribing information for the antiviral drug, the Food and Drug Administration announced Aug. 1.

Boceprevir (Victrelis), a protease inhibitor approved for treating hepatitis C in 2011, interacts with cyclosporine, tacrolimus (Prograf), escitalopram (Lexapro), atorvastatin (Lipitor), and pravastatin (Pravachol), according to the FDA statement.

The new information states that, when administered with boceprevir, exposure to atorvastatin increases. When the two drugs are used together, the lowest effective dose of atorvastatin should be used, not to exceed a daily dose of 40 mg, according to the FDA.

Dose adjustments of cyclosporine should be anticipated when it is given with boceprevir, and "should be guided by close monitoring of cyclosporine blood concentrations, and frequent assessments of renal function and cyclosporine-related side effects."

When administered with boceprevir, exposure of escitalopram "was slightly decreased," the statement said. Although selective serotonin reuptake inhibitors (SSRIs) such as escitalopram have a wide therapeutic index, it may be necessary to adjust the dosage when it is administered with boceprevir.

Coadministration of boceprevir with pravastatin increases exposure to pravastatin, but pravastatin can be started at the recommended dosage when coadministered with boceprevir. "Close clinical monitoring is warranted," the statement said.

Giving tacrolimus and boceprevir together "requires significant dose reduction and prolongation of the dosing interval for tacrolimus, with close monitoring of tacrolimus blood concentrations and frequent assessments of renal function and tacrolimus-related side effects," the statement said.

Boceprevir is manufactured in a capsule formulation by Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., and is taken by mouth three times a day.

The drug-drug interaction data are from in vivo drug interaction trials, which the company conducted as part of its postmarketing commitments.

At a meeting in April 2011, an FDA advisory panel enthusiastically supported the approval of boceprevir for treating hepatitis C infection because of the antiviral’s efficacy but emphasized that postmarketing studies on interactions with other drugs, including antidepressants, were needed.

Serious adverse events associated with boceprevir should be reported to MedWatch or by phone at 800-332-1088.

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