Famotidine and Pradaxa (Dabigatran) Interaction
Famotidine does not interact with dabigatran (Pradaxa) and can be safely co-administered without dose adjustments or timing modifications. 1
Mechanism and Evidence
Famotidine has no effect on dabigatran pharmacokinetics because dabigatran absorption is not pH-dependent, unlike some other medications that require gastric acidity for optimal absorption. 1
The lack of interaction has been directly demonstrated in controlled pharmacokinetic studies with apixaban (another direct oral anticoagulant), where famotidine showed no effect on drug absorption or plasma concentrations, and this principle extends to dabigatran given its similar physicochemical properties. 1
Famotidine does not inhibit P-glycoprotein (P-gp), which is the primary transporter affecting dabigatran absorption and the main pathway for clinically significant drug interactions with dabigatran. 2
Critical Distinction from Proton Pump Inhibitors
Proton pump inhibitors (PPIs) like omeprazole and pantoprazole DO interact with dabigatran through P-gp inhibition, significantly reducing dabigatran plasma levels by approximately 50% for both trough and peak concentrations. 3, 4
When PPIs must be used with dabigatran, administration timing becomes critical: dabigatran should be given 2 hours before the PPI in the fasted state to minimize P-gp-mediated interaction. 4
This interaction does NOT apply to famotidine, which operates through a different mechanism (H2-receptor antagonism) without P-gp effects. 1
Practical Clinical Application
No dose adjustment of dabigatran is needed when co-administered with famotidine. 1
No timing separation between doses is required - both medications can be taken together without concern. 1
Famotidine remains an excellent choice for gastric acid suppression in patients taking dabigatran who require gastroprotection, particularly given that dabigatran itself increases gastrointestinal bleeding risk. 5, 6
Drugs That DO Interact with Dabigatran
For context, clinically significant interactions with dabigatran occur with:
Strong P-gp inhibitors (ketoconazole, quinidine) which are contraindicated and can more than double dabigatran plasma concentrations. 2
Moderate P-gp inhibitors (amiodarone, verapamil, dronedarone) which increase dabigatran exposure by 12-60% depending on timing and formulation. 2
P-gp inducers (rifampin, St. John's wort) which decrease dabigatran exposure by up to 66% and should be avoided. 2