Management of digoxin therapy using pharmacokinetics in a patient undergoing continuous venovenous hemofiltration

Purpose. The management of digoxin therapy using pharmacokinetics in a patient undergoing continuous venovenous hemofiltration (CVVH) is reported. Summary. A 46-year-old African-American woman with New York Heart Association class IV, American College of Cardiology-American Heart Association stage D heart failure arrived from an outside facility with complaints of dyspnea after minimal exertion, orthopnea, and lower-extremity edema. A transthoracic echocardiogram revealed an estimated left ventricular ejection fraction of 15%. The patient subsequently required left ventricular assist device placement on hospital day 5 as a potential bridge to transplantation. A total digoxin loading dose of 500 μg i.v. (8.2 μg/kg) was given in two divided doses six hours apart. The next morning, the serum digoxin concentration was 1.9 ng/mL, and the patient was started on a maintenance digoxin dosage of 125 μg i.v. daily. On postoperative day (POD) 20, the patient developed acute kidney injury, and CVVH was initiated. The sieving coefficient (Sc), transmembrane clearance (CL_tm), digoxin concentration in ultrafiltration fluid (C_uf), and need for supplemental digoxin were determined to account for CVVH-associated digoxin loss. After 14 days of CVVH, the patient's clinical condition improved, and CVVH was transitioned to intermittent hemodialysis. On POD 66, the patient was discharged to an extended-care facility without adverse reactions related to digoxin therapy. Conclusion. Analysis of serum digoxin concentration and digoxin C_uf values suggested that digoxin was cleared by CVVH, allowed calculation of Sc and CL_tm values, and facilitated determination of digoxin requirements in a critically ill patient requiring CVVH.