diltiazem and Duragesic 100 Interactions

Interactions between diltiazem and Duragesic 100 (fentanyl)

diltiazem and fentanyl (Major Drug-Drug)

MONITOR CLOSELY: Coadministration with potent and moderate inhibitors of CYP450 3A4 may increase the plasma concentrations of fentanyl, which is primarily metabolized by the isoenzyme. Increased fentanyl concentrations could conceivably increase or prolong adverse drug effects and may cause potentially fatal respiratory depression.

MANAGEMENT: Patients receiving fentanyl in combination with potent or moderate CYP450 3A4 inhibitors (e.g., azole antifungal agents, protease inhibitors, ketolide and certain macrolide antibiotics, aprepitant, diltiazem, dalfopristin-quinupristin, delavirdine, imatinib, nefazodone, verapamil) should be carefully monitored, and dosage adjustments made accordingly if necessary. Patients and/or their caregivers should be advised to seek medical attention if potential signs and symptoms of toxicity occur such as dizziness, confusion, fainting, extreme sedation, bradycardia, slow or difficult breathing, and shortness of breath. Patients treated with transdermal formulations of fentanyl should be cautioned that drug interactions and drug effects may be observed for a prolonged period beyond removal of the patch, as significant amounts of fentanyl are absorbed from the skin for 17 hours or more after the patch is removed.