This summer, the FDA convened a panel of scientific advisers to evaluate the suicide risks of 11 antiseizure drugs, including Neurontin. Crunching data from 210 clinical trials, the agency found a small increased risk: Two of 1,000 patients taking the medications experienced suicidal thoughts or behavior. When millions of people are taking a drug, even such slim odds can have consequences.
The advisory panel accepted the FDA's findings, but voted against imposing the government's strongest warning on the drugs, saying that could do more harm than good. The FDA is considering how to communicate the risks to patients.
"Even though a drug is identified as a drug for weight control, or smoking cessation, or asthma, these drugs often also get into the brain, so there is always the potential for having psychiatric side effects," said Dr. Thomas Laughren, head of the FDA's division of psychiatric products. "But we don't have any unifying hypothesis as to why very different classes of drugs have psychiatric side effects."
The FDA has tools to assess the suicide risks of medications. Researchers at Columbia University have developed a system for collecting and analyzing data about suicidal thoughts and actions among people who enroll in drug trials. The FDA helped pay for the research, but the agency does not require drugmakers to use the system, a puzzling oversight to independent experts.
"I can't see any reason why it should not be widely and regularly used during drug development," said Larry Sasich, a professor of pharmacy practice at the Lake Erie School of Osteopathic Medicine in Erie, Pa.
But the FDA's Laughren said that while many drugs can affect the brain, "there is no compelling reason to think that more than a few are associated with suicidality."
"Whether or not any of these drugs cause suicidal thoughts and behavior is the critical question we need to answer; up to now, we have not answered that," said Kelly Posner, a Columbia researcher who led the effort to develop the screening system. "Debunking false notions of risk is just as important to the public health as knowing about risks that exist."