Prospective evaluation of serum amiodarone concentrations when administered via a nasogastric tube into the stomach conduit after transthoracic esophagectomy.
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), followed 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] microg/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] microg/mL; P = 0.02) and on POD 4 (0.30 [0.34] vs 0.87 [0.16] microg/mL; P < 0.001). Serum amiodarone concentrations were undetectable in 33% and 50% of patients in the esophagectomy group on PODs 2 and 4, respectively, compared with 0% in the PR group (both, P = 0.03).


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. Nasogastric administration of amiodarone should probably be avoided for prophylaxis or treatment of postesophagectomy tachyarrhythmias.
Department of Pharmacy Practice, School of Pharmacy and Pharmaceutical Sciences, Purdue University, Indianapolis, Indiana 46202, USA. jtisdale@iupui.edu
James E
JE
Tisdale
Heather A
HA
Wroblewski
Zane T
ZT
Hammoud
Karen M
KM
Rieger
Jerry V
JV
Young
Donna S
DS
Wall
Kenneth A
KA
Kesler
D000638:Amiodarone / Q000008:administration & dosage / Q000097:blood*; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage / Q000097:blood*; D001682:Biological Availability; D004333:Drug Administration Routes; D016629:Esophagectomy; D005260:Female; D006785:Hospitals, University; D006801:Humans; D007196:Indiana; D007441:Intubation, Gastrointestinal; D008297:Male; D008875:Middle Aged; D011013:Pneumonectomy; D011183:Postoperative Complications / Q000517:prevention & control; D011446:Prospective Studies; D013270:Stomach
D000889:Anti-Arrhythmia Agents; D000638:Amiodarone