Drug Interactions between budesonide / formoterol and temsirolimus

MONITOR: Coadministration of sirolimus or tacrolimus with other drugs that are also metabolized by CYP450 3A4 may result in elevated plasma concentrations of the macrolide immunosuppressant and/or the coadministered drug(s). The mechanism is decreased drug clearance due to competitive inhibition of CYP450 3A4 activity. Although clinical data are lacking, the possibility of prolonged and/or increased pharmacologic effects of the drugs should be considered.

MANAGEMENT: Pharmacologic responses and/or plasma drug levels should be monitored more closely whenever a macrolide immunosuppressant or another substrate of CYP450 3A4 is added to or withdrawn from therapy, and the dosage(s) adjusted as necessary.

Although they are often combined in clinical practice, the concomitant use of beta-2 adrenergic agonists and corticosteroids may result in additive hypokalemic effects. Since beta-2 agonists can sometimes cause QT interval prolongation, the development of hypokalemia may potentiate the risk of ventricular arrhythmias including torsade de pointes. However, clinical data are limited, and the potential significance is unknown. Patients who are receiving systemic or nebulized formulations of beta-2 agonists, high dosages of inhaled beta-2 agonists, or systemic corticosteroid therapy may be at a greater risk of developing hypokalemia.