Drug Interaction Report

MONITOR: The use of mTOR (mammalian target of rapamycin) inhibitors has been associated with the development of angioedema, and coadministration with other drugs that are also known to cause angioedema such as ACE inhibitors, angiotensin II receptor antagonists, and renin inhibitors may increase the risk. In a pooled analysis of everolimus oncology clinical trials, the incidence of angioedema in patients taking everolimus with an ACE inhibitor was 6.8% compared to 1.3% in the control arm with an ACE inhibitor. The onset of angioedema may sometimes be delayed. According to the product labeling for temsirolimus, angioneurotic edema-type reactions have occurred two months after initiation of therapy in some patients who received concomitant ACE inhibitors.

MANAGEMENT: Clinicians and patients should be aware of the potential for increased risk of angioedema when mTOR inhibitors are prescribed with other drugs that are also known to cause angioedema. Patients should be advised to promptly discontinue these medications and seek medical attention if they develop signs or symptoms suggestive of angioedema such as swelling of the face, extremities, eyes, lips, or tongue, and difficulty swallowing or breathing.

ADJUST DOSING INTERVAL: Consumption of food can decrease the rate and extent of gastrointestinal absorption of sirolimus. Also, the consumption of grapefruit juice may result in increased sirolimus trough concentrations.

MANAGEMENT: Experts recommend that this drug be taken either at least one hour prior to eating or consistently with or without food to avoid variations in sirolimus blood levels. The manufacturer recommends against using grapefruit juice for dilution of sirolimus doses. Patients should be monitored for clinical and laboratory evidence of altered immunosuppressant effects.