NRNP 6566 Knowledge Check Week 3

NRNP 6566 Knowledge Check Week 3 QUESTION 1 1. A 63-year-old female has been successfully cardioverted and is now on amiodarone for rhythm maintenance. The patient is on the following medications: Warfarin 10 mg po daily Lisinopril 20 mg po daily Amiodarone 400 mg po daily Prilosec 20 mg po daily Digoxin 4250 mcg po daily What interactions are possible and how would you monitor and adjust for them. Amiodarone has possible complex interactions with multiple medications. It has an effect on warfarin metabolism. Amiodarone is a potent inhibitor of cytochrome P450 enzymes and inhibition of these enzymes will cause an increased plasma concentration and decreased clearance; thereby increasing the prothrombin time and INR placing the patient at increased risk for bleeding complications. Hence, when given together, warfarin dose should be decreased and frequent INR monitoring should be done. Amiodarone also interacts with digoxin. It increases digoxin concentrations through the inhibition of P-glycoprotein mediated efflux transporter that facilitates digoxin elimination from the body. Amiodarone increases the serum drug levels of digoxin. Due to this, when given together, digoxin dose should be reduced and levels are closely monitored.