Drug Interactions

Impact of Other Drugs on Dabigatran

P-gp Inducers
Rifampin: Rifampin 600 mg once daily for 7 days followed by a single dose of dabigatran decreased its AUC and Cmax by 66% and 67%, respectively. By Day 7 after cessation of rifampin treatment, dabigatran exposure was close to normal [see Warnings and Precautions (5.3) and Drug Interactions (7)].

P-gp Inhibitors
In studies with the P-gp inhibitors ketoconazole, amiodarone, verapamil, and quinidine, the time to peak, terminal half-life, and mean residence time of dabigatran were not affected. Any observed changes in Cmax and AUC are described below.

Dronedarone: Exposure to dabigatran is higher when it is administered with dronedarone than when it is administered alone (1.7- to 2-fold).

Ketoconazole: Ketoconazole increased dabigatran AUC0-∞ and Cmax values by 138% and 135%, respectively, after a single dose of 400 mg, and 153%, and 149%, respectively, after multiple daily doses of 400 mg.

Verapamil: When dabigatran etexilate was coadministered with oral verapamil, the Cmax and AUC of dabigatran were increased. The extent of increase depends on the formulation of verapamil and timing of administration. If verapamil is present in the gut when dabigatran is taken, it will increase exposure to dabigatran with the greatest increase observed when a single dose of immediate-release verapamil is given one hour prior to dabigatran (AUC increased by a factor of 2.4). If verapamil is given 2 hours after dabigatran, the increase in AUC is negligible. In the population pharmacokinetics study from RE-LY, no important changes in dabigatran trough levels were observed in patients who received verapamil.

Amiodarone: When dabigatran etexilate was coadministered with a single 600 mg oral dose of amiodarone, the dabigatran AUC and Cmax increased by 58% and 50%, respectively. The increase in exposure was mitigated by a 65% increase in the renal clearance of dabigatran in the presence of amiodarone. The increase in renal clearance may persist after amiodarone is discontinued because of amiodarone’s long half-life. In the population pharmacokinetics study from RE-LY, no important changes in dabigatran trough levels were observed in patients who received amiodarone.

Quinidine: Quinidine was given as 200 mg dose every 2 hours up to a total dose of 1000 mg. Dabigatran etexilate was given over 3 consecutive days, the last evening dose on Day 3 with or without quinidine pre-dosing. Concomitant quinidine administration increased dabigatran’s AUC and Cmax by 53% and 56%, respectively.

Clarithromycin: Coadministered clarithromycin had no impact on the exposure to dabigatran.

Other Drugs
Clopidogrel: When dabigatran etexilate was given concomitantly with a loading dose of 300 mg or 600 mg clopidogrel, the dabigatran AUC and Cmax increased by approximately 30% and 40%, respectively. The concomitant administration of dabigatran etexilate and clopidogrel resulted in no further prolongation of capillary bleeding times compared to clopidogrel monotherapy. When comparing combined treatment and the respective mono-treatments, the coagulation measures for dabigatran’s effect (aPTT, ECT, and TT) remained unchanged, and inhibition of platelet aggregation (IPA), a measurement of clopidogrel’s effect, remained unchanged.

Enoxaparin: Enoxaparin 40 mg given subcutaneously for 3 days with the last dose giv