US lawsuit claims Pfizer failed to warn of Cardura problems

Patients who have been treated with Pfizer's antihypertensive Cardura(doxazosin mesylate) have filed a class action lawsuit against the firm claiming that it failed to warn them of serious risks related to the drug.

The suit relates to the results of a substudy of the 42,000-patient Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT), presented in March, which found that patients with high blood pressure who receive treatment with Cardura were more likely to go on to develop congestive heart failure than those treated with the diuretic chlorthalidone (Marketletter April 10).

Although Cardura has been on the market since 1987 for hypertension, ALLHAT is the only large-scale trial to compare its effects on CHF risk to a diuretic. The lawsuit, which was filed in a New York federal court on May 30, claims that Pfizer failed to take any "affirmative" steps to communicate the findings of the study to patients on Cardura, and is seeking to mandate emergency notification of all users of the drug. Reuters notes that more than one million people in the USA are taking the drug, for hypertension as well as for benign prostatic hyperplasia, and that it has annual sales of around $800 million.