Product News and Recalls

Drug interactions a concern for users of blood thinners

A column by Dr. Anthony L. Komaroff in North Carolina’s Daily Reflector cautions about the effects of drug interactions for patients taking the medication warfarin – an anticoagulant, or blood thinner.

Komaroff writes that some antibiotics and antifungal drugs increase warfarin’s ability to stop blood clotting, but others do the opposite. Some topical antibiotics that are applied directly to the skin can also interfere with warfarin. He recommends that anyone taking warfarin get regular blood tests.

Although alternatives to warfarin are available, many doctors are reluctant to prescribe them because of safety concerns.

Pradaxa was introduced as a more convenient alternative to warfarin, because patients taking it didn’t require regular blood testing or dietary restrictions. But the nonprofit Institute for Safe Medication Practices recently estimated that 542 reports of deaths associated with Pradaxa were reported to the FDA in 2011, topping all other medicines.

In the column, Komaroff is responding to a letter writer who received a stent, which is a wire mesh cylinder that opens up the middle of an artery partially blocked by cholesterol-rich plaque, or atherosclerosis.

Under some conditions, our blood’s ability to clot is beneficial and necessary, as when we cut our skin or suffer a bleeding stomach ulcer.

But placement of a stent can make clots form more easily, Komaroff writes. And if a clot forms in the stent, the blood supply can suddenly shut off and trigger a heart attack.

That’s why doctors prescribe anticoagulants to reduce the risk of clots for at least a year after a stent is placed. Warfarin is also used for other conditions that increase the risk of blood clots, including artificial heart valves, the irregular heart rhythm called atrial fibrillation, and blood clots in the legs (deep venous thrombosis) that may travel to the lungs.

Patients should consult their doctors before making any changes in their medication. A consultation with a Pradaxa lawyer is also important if there are significant injuries while on Pradaxa.

See the column here: