Drug Interaction Report

ADJUST DOSING INTERVAL: Aluminum-containing oral medications may decrease the absorption of allopurinol and reduce its therapeutic effect. The mechanism of this interaction is unknown; however, it may involve the binding of aluminum to allopurinol in the gastrointestinal tract and preventing its absorption.

MANAGEMENT: Allopurinol should be administered at least 3 hours before or after aluminum-containing medications.

ADJUST DOSING INTERVAL: The tolerability of allopurinol may be improved by giving it after a meal. Additionally, when the dose is greater than 300 mg, dividing the total daily dose into smaller doses administered more often may be appropriate to help minimize gastrointestinal irritation.

MONITOR: Concomitant use of allopurinol with central nervous system (CNS) depressants, including alcohol, may potentiate adverse effects such as somnolence and sedation.

MANAGEMENT: To improve tolerability, some manufacturers suggest administering allopurinol after a meal. Additionally, if the daily dose is greater than 300 mg, administering allopurinol in divided doses may help reduce gastrointestinal intolerance. Patients should also be counseled to avoid or limit consumption of alcohol and to avoid activities requiring mental alertness such as driving or operating hazardous machinery until they know how the medication affects them.

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.