Toronto—Two commonly used statins can increase the amount of dabigatran etexilate absorbed by the body and boost the risk of bleeding in patients on the blood thinner, according to a new Canadian study.
Bleeding is a known possible adverse effect of dabigatran etexilate, a drug often used for preventing stroke in patients with atrial fibrillation, and that situation sometimes requires emergency treatment or hospital admission, according to an article published recently in CMAJ (Canadian Medical Association Journal).
To look at the risks, St. Michael’s Hospital–led researchers conducted two studies involving Ontario residents over age 65 who started dabigatran etexilate between 2012 and 2014. Participants—both cases and controls—received a single statin in the 60 days preceding the index date.
Results indicate that use of both simvastatin and lovastatin was associated with a higher risk of major hemorrhage, for an adjusted odds ratio of 1.46. Those findings led the researchers to recommend that preferential use of other statins be considered in patients prescribed dabigatran etexilate.
“We found no difference in the risk of stroke in patients receiving dabigatran etexilate who were prescribed lovastatin or simvastatin versus other statins,” explained lead author Tony Antoniou, PhD. “However, an increase in the risk of bleeding requiring hospital admission or emergency department visits was seen with lovastatin and simvastatin compared with the other statins.”
Background information in the article points out that dabigatran etexilate is a prodrug whose absorption is opposed by intestinal P-glycoprotein; it is converted by carboxylesterase to its active form, dabigatran. Simvastatin and lovastatin are potent inhibitors of P-glycoprotein and carboxylesterase, and they potentially could increase the risk of hemorrhage with dabigatran etexilate or decrease its effectiveness, the researchers caution.
“These results suggest that a clinically important drug interaction exists between dabigatran etexilate and both simvastatin and lovastatin, and that other statins should be used preferentially when such treatment is needed in patients getting dabigatran etexilate,” the authors conclude.
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