Drug Interaction Report

GENERALLY AVOID: Theoretically, the coadministration of nonsteroidal anti-inflammatory drugs (NSAIDs) and thrombin inhibitors may potentiate the risk of bleeding. NSAIDs interfere with platelet adhesion and aggregation and may prolong bleeding time in healthy individuals. While these effects are generally slight and of relatively short duration for most NSAIDs (except aspirin) at recommended dosages, they may be of pronounced clinical significance when combined with the effects of thrombin inhibitors on the clotting cascade. NSAIDs are also known to cause dose-related gastrointestinal bleeding, which may be complicated by anticoagulant therapy. However, little clinical data exist regarding an actual interaction.

MANAGEMENT: Until further data are available, products containing NSAIDs, especially if given chronically or in high dosages, should preferably be avoided in patients receiving thrombin inhibitors. Close clinical and laboratory observation for bleeding complications is recommended if concurrent therapy is necessary.

H2 antagonists may alter the pharmacokinetic disposition of some nonsteroidal anti-inflammatory drugs (NSAIDs), resulting in increased or decreased plasma concentrations. Data have been varied, even for the same NSAID. The mechanism may involve inhibition of metabolism, changes in gastric pH resulting in altered absorption, and/or reduced urinary elimination of the affected NSAIDs. Statistically significant changes have been small and of limited clinical significance when interactions have been observed.

GENERALLY AVOID: The concurrent use of aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) and ethanol may lead to gastrointestinal (GI) blood loss. The mechanism may be due to a combined local effect as well as inhibition of prostaglandins leading to decreased integrity of the GI lining.

MANAGEMENT: Patients should be counseled on this potential interaction and advised to refrain from alcohol consumption while taking aspirin or NSAIDs.

H2 antagonists may reduce the clearance of nicotine. Cimetidine, 600 mg given twice a day for two days, reduced clearance of an intravenous nicotine dose by 30%. Ranitidine, 300 mg given twice a day for two days, reduced clearance by 10%. The clinical significance of this interaction is not known. Patients should be monitored for increased nicotine effects when using the patches or gum for smoking cessation and dosage adjustments should be made as appropriate.