Drug Interaction Report

MONITOR: Coadministration of daclizumab with other agents known to induce hepatotoxicity may increase the risk of liver injury. Serious drug-related hepatic injury, including liver failure and autoimmune hepatitis, has been reported across controlled and open-label studies in 1.7% of daclizumab-treated patients and may occur at any time during treatment and up to 5 months after treatment cessation. Fatal cases have occurred. In addition, cases of hepatic injury have occurred in patients taking daclizumab concomitantly with other hepatotoxic drugs; however, the contributory role of these other medicines has not been established.

MANAGEMENT: Caution is advised if daclizumab is used with other potentially hepatotoxic agents, including non-prescription products and herbal supplements. Patients treated with daclizumab should have serum transaminase levels and total bilirubin measured prior to initiation of treatment and monthly during treatment in accordance with the manufacturer's recommendations, and the dosing adjusted or interrupted as necessary. Patients should be advised to seek medical attention if they experience potential signs and symptoms of hepatotoxicity such as fever, rash, itching, anorexia, nausea, vomiting, fatigue, malaise, right upper quadrant pain, dark urine, pale stools, and jaundice.

Food enhances the oral absorption and bioavailability of tenofovir, the active entity of tenofovir disoproxil fumarate. According to the product labeling, administration of the drug following a high-fat meal increased the mean peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of tenofovir by approximately 14% and 40%, respectively, compared to administration in the fasting state. However, administration with a light meal did not significantly affect the pharmacokinetics of tenofovir compared to administration in the fasting state. Food delays the time to reach tenofovir Cmax by approximately 1 hour. Tenofovir disoproxil fumarate may be administered without regard to meals.