Prospective evaluation of serum amiodarone concentrations when administered via a nasogastric tube into the stomach conduit after transthoracic esophagectomy

Abstract Background: Atrial fibrillation occurs in up to 46% of patients following esophagectomy; amiodarone may be used for prophylaxis or treatment in these patients. There are few data regarding drug absorption following esophagectomy. Objective: The aim of this study was to determine serum amiodarone concentrations when the drug is administered into the stomach conduit following esophagectomy. Methods: Patients who underwent noncardiac thoracic surgery were enrolled in this prospective, controlled study. One group of patients underwent esophagectomy, and a second group of patients comprised a control group who underwent pulmonary resection (PR). A continuous IV amiodarone infusion (0.73 mg/min) was initiated at anesthesia induction and continued for 24 hours (total IV dose 1050 mg), ollowed by 400 mg via a nasogastric tube (in the esophagectomy group) or orally (in the PR group) every 12 hours for 6 days. Blood samples for determination of serum amiodarone concentrations were obtained at completion of the infusion (postoperative day [POD] 1), and before the third (POD 2) and seventh (POD 4) enteral doses. Results: A total of 27 patients were enrolled (esophagectomy group, 13 patients; PR group, 14 patients). Patients in the 2 groups had statistically similar ages (mean [SD], 60 [10] vs 53 [10] years; P = 0.07) and proportions of men (12/13 [92%] vs 8/14 [57%]; P = 0.08). Patients in the 2 groups were statistically similar with respect to race (white, 13/13 [100%] vs 13/14 [93%]) and preoperative weight (mean [SD], 83.3 [11.5] vs 77.7 [18.6] kg). On POD 1, age-adjusted and sex-adjusted serum amiodarone concentrations were not significantly different in the esophagectomy group versus the PR group (mean [SD] 0.65 [0.22] vs 0.84 [0.20] μg/mL). Mean (SD) serum amiodarone concentrations were significantly lower in the esophagectomy group on POD 2 (0.35 [0.27] vs 0.60 [0.18] μg/mL; P = 0.02) and on POD 4 (0.30 [0.34] vs 0.87 [0.16] µg/mL; P Conclusions: Serum amiodarone concentrations were significantly lower (and in some cases undetectable) when the drug was administered via a nasogastric tube into the stomach conduit in patients after esophagectomy compared with those concentrations after oral administration in a PR population. These data were presented as a poster presentation at the Spring Practice and Research Forum, American College of Clinical Pharmacy, April 9, 2006, Monterey, California.