Study Indicates Need For Better Presentation of Drug-safety Information
On November 18, 2005 the medical journal Pharmacoepidemiology and Drug Safety published findings from a new study which reveals that doctors and patients, both, often ignore the content of "black-box" warnings on the package insert, or label, of certain prescription drugs. The FDA requires that drug companies put this black-box warning on some drugs in order to emphasize significant drug-safety information. The fact that doctors and patients are not paying attention to the content of some black-box warnings suggests that this method of warning about serious side effects in not working well.
The study found in the November 18 edition of Pharmacoepidemiology and Drug Safety was led by Anita Wagner, an assistant professor in the department of ambulatory care and prevention at Harvard Medical School. Working with researchers from Harvard Medical School as well as several hospitals and health plans, Dr. Wagner's team reviewed claims data for approximately one million patients who were enrolled in ten health plans across the country. In particular, the researchers investigated the "compliance" rate of patients who received one of 19 prescription drugs that the FDA had required include a black-box warning on its label.
The researchers found that compliance with the warnings varied substantially -- from extremely good for certain prescription drugs for which a black-box warning states cannot be taken during pregnancy, to poor for some drugs with a black-box warning about required diagnostic tests.
Dr. Wagner said the study's results indicate to her that more specific black-box warnings -- such as do not use this drug during pregnancy -- resulted in higher compliance rates than black-box warnings that were relatively vague in nature. Valproic acid, which is used to treat epileptic seizures, migraines, and bipolar disorder, was offered as an example of a vague, as opposed to specific, warning. The package insert for valproic acid has a black-box warning about liver toxicity. It states that liver tests should be performed "prior to therapy and at frequent intervals thereafter, especially during the first six months." The study led by Dr. Wagner found, however, that 48.6% of all valproic acid prescriptions were issued without any initial liver test, and that 29.5% of patients who filled a prescription for valproic acid did not get the ongoing liver tests.
When asked for comment, the FDA's Paul J. Seligman, who heads up the agency's post-marketing drug surveillance, said that the study by Dr. Wagner and her colleagues demonstrate the need for more research concerning the best method by which to give doctors and patients clearer warnings about serious side effects.
(Posted by: Tom Lamb)