Research/Practice Reports: Perspectives on Digoxin Absorption from Small Bowel Resections

Abstract

Digoxin is a commonly prescribed medication for a variety of cardiovascular abnormalities. The therapeutic index of digoxin is considered narrow and drug is absorbed predominantly from the duodenum and upper jejunum. When the small intestine is intact, the absorption can vary; therefore, in the case of a small bowel resection or bypass, this erratic absorption may be accentuated. There is some controversy concerning the effect of small bowel resection or bypass on the absorption of digoxin. Some investigators have shown that small bowel resection or bypass decreases the absorption of oral digoxin, whereas others report no change in absorption. When the study methodologies were evaluated, certain common factors that support each view were found. In most studies reporting malabsorption, a solid dosage form of digoxin was used. Studies reporting no change in absorption investigated a solution dosage form.

Malabsorption causing failure of pharmacological therapy in the treatment of atrial fibrillation

“…One such option is to consider other preparations of medication that either have greater bioavailability or are absorbed from other areas of the bowel. In this case, a liquid form of digoxin was used as those studies that have shown malabsorption of digoxin following intestinal resection generally used tablet formulations of digoxin, while those that showed no difference used liquid formulations [5]. Alternatively IV preparations may be used.…”

Short small bowel in children. Complications and treatment strategies

“…Propantheline appears to increase contact time of digoxin with the absorption site, thereby increasing the amount of digoxin absorbed from the administered tablets. Metoclopramide, which increases the gastrointestinal motility, seems to decrease the amount of digoxin absorbed [46].…”

“…This may be related to inadequate dissolution of the tablet before it passes the absorption sites and not necessarily to a defect at the absorption site. Several studies suggest that digoxin absorption may be improved in patients with intestinal resection when given in liquid dosage form such as elixir [46][47][48], also after radiation induced malabsorption [47]. Even in a patient with an end jejunostomy and only 12-15 cm of remaining jejunum a diminished absorption of oral digoxin was observed, but digoxin elixir achieved a therapeutic serum concentration [45].…”

Drug Absorption in Gastrointestinal Disease and Surgery

“…Two other trials with tablets revealed impairment of digoxin ab~o r p t i o n .~~.~~ Another, conducted in patients who had undergone jejunoileal bypass, failed to observe any alterations.60 However, a reveiw article suggested that the results may have been influenced by the surgical procedure performed, which may have left a majority of the musoca involved in digoxin absorption intact. 55 Clinically, this indicates that, in patients who are predisposed to malabsorption and have demonstrated alterations in bioavailability of digoxin tablets, a liquid dosage form, such as the elixir presently marketed, should be employed. A case report suggests that this may be effective.6' A patient whose regimen included digoxin tablets received a course of radiation therapy and developed radiation-induced malabsorption of the drug.…”