Drug Interactions between Lanoxin and sucralfate

ADJUST DOSING INTERVAL: The administration of sucralfate with enteral nutrition may result in precipitation and the formation of bezoars that may obstruct feeding tubes. The proposed mechanism is the formation of an insoluble aluminum-protein complex between the aluminum in the sucralfate and the protein in the enteral feeding. In addition, sucralfate may not become activated due to the alkaline pH of enteral nutrition products.

MANAGEMENT: Some experts recommend separating the sucralfate doses from enteral feedings by at least 1 hour. Alternatively, consideration may be given to proton pump inhibitors or H2 antagonists.

Administration of digoxin with a high-fiber meal has been shown to decrease its bioavailability by almost 20%. Fiber can sequester up to 45% of the drug when given orally. Patients should be advised to maintain a regular diet without significant fluctuation in fiber intake while digoxin is being titrated.

Grapefruit juice may modestly increase the plasma concentrations of digoxin. The mechanism is increased absorption of digoxin due to mild inhibition of intestinal P-glycoprotein by certain compounds present in grapefruits. In 12 healthy volunteers, administration of grapefruit juice with and 30 minutes before, as well as 3.5, 7.5, and 11.5 hours after a single digoxin dose (0.5 mg) increased the mean area under the plasma concentration-time curve (AUC) of digoxin by just 9% compared to administration with water. Moreover, P-glycoprotein genetic polymorphism does not appear to influence the magnitude of the effects of grapefruit juice on digoxin. Thus, the interaction is unlikely to be of clinical significance.