FDA Probes Agents Affecting Clopidogrel Response

The FDA is investigating whether the antiplatelet drug clopidogrel is less effective in people with some genetic factors and when taken with other drugs, including proton pump inhibitors (PPIs).

Studies indicate that certain polymorphisms may cause patients to metabolize clopidogrel differently.

In addition, research has shown that PPIs inhibit the enzyme that converts clopidogrel to its active form, potentially rendering it less effective. (Clopidogrel and PPIs are commonly used in tandem because clopidogrel can irritate the stomach, while PPIs decrease stomach acid.)

Until the manufacturers have finished further studies, the FDA recommends that healthcare providers:

• continue to prescribe clopidogrel, because of its demonstrated benefits;

• reevaluate the need for a PPI if a patient is taking clopidogrel.