The Food and Drug Administration last year warned patients who are taking the anti-clotting drug Plavix against taking the acid-reducing medications Prilosec or Nexium with it because either of the proton pump inhibitors could reduce Plavix's efficacy, but a new consensus document issued Monday by three medical groups says that the benefits of the combination sometimes outweigh the potential risks.
Plavix, with more than $9 billion in sales annually, is the second-best-selling drug in the world. It is widely used to prevent clotting in patients who have undergone bypass surgery, angioplasty, stenting and certain other procedures. Because Plavix leaves patients more susceptible to bleeding, physicians frequently prescribe acid-reducing drugs to reduce the risk of stomach irritation that could lead to bleeding. But the FDA warned in November of 2009 that taking Prilosec, Nexium or the generic drug omeprazole could reduce the efficacy of Plavix by 50%. Instead, the FDA suggested that patients take a drug from the family known as H2 inhibitors, such as Zantac. Those drugs, however, are not as effective at reducing acid.
Dr. Neena S. Abraham, a gastroenterologist at the Baylor College of Medicine and chairwoman of the writing committee for the new document, said the committee was concerned that interactions between the two classes of drugs observed in the test tube were not necessarily being replicated in humans and that a recent study in people did not support the initial conclusions of the FDA. The committee said that the anti-acid medications should continue to be used for those with a history of gastrointestinal bleeding as well as those with multiple risk factors for GI bleeding, including: a history of peptic ulcer disese; advanced age; use of anticoagulants, steroids, non-steroidal anti-inflammatory drugs; and Helicobacter pylori infection. The drugs are not recommended for patients who have a lower risk of upper GI bleeding and thus have much less potential to benefit from prophylactic therapy.