* IOM says risks of certain drugs become apparent over years
* Says FDA should monitor safety through drug 'lifecycle'
* Says FDA should create public document for drug risks
* FDA says supports transparency, concerned about costs
By Anna Yukhananov
WASHINGTON, May 1 (Reuters) - The U.S. Food and Drug Administration should review drugs on a regular basis for as long as they are on the market in order to catch any new safety issues, according to a report from an independent research body.
The Institute of Medicine, which often advises the government on scientific matters, said the FDA should then create a comprehensive, publicly available document that reflects risks that crop up throughout the "lifecycle" of the drug.
The FDA has been criticized for not quickly responding to dangerous side effects that become more evident after a product is brought to market, such as with Vioxx, a painkiller that Merck & Co In pulled five years after approval because of a link to heart attacks and strokes.
"It's impossible to know all the risks and benefits of a drug before approval," said Dr. Ruth Faden, co-chair of the IOM committee. The IOM called on the FDA to monitor drug safety at regular intervals over time.
The IOM's recommendations are not binding, and the FDA expressed some reservations about costs.
"We support the general concept of enabling the public to be able to clearly monitor relevant safety issues for all drugs," said FDA spokeswoman Sandy Walsh.
"However, we feel it would be very challenging to implement this recommendation within our current resources without seriously compromising other critical regulatory activities."
Currently, the FDA must only check for new safety issues after the drug has been sold for 18 months, or after it has been used by 10,000 patients, whichever is later. It relies upon reports of side effects submitted by the drugmaker, doctors or patients.
The FDA did get greater power under a 2007 law to compel drugmakers to do additional post-approval safety trials or change their labels in response to new information, rather than relying on voluntary action from the companies.
In a report last month, the FDA said it now spends as much effort and resources on tracking a drug after it is approved as it does in the pre-approval process.
It said it has required companies to do 385 post-market studies since 2008, and to change the label based on new safety information 65 times.
Dr. Faden, who is also director of the Johns Hopkins Berman Institute of Bioethics, said extensive post-approval monitoring is critical because safety concerns with a drug may only become apparent once it has been used for many years, and by thousands of patients.
"We'd like to think that when a drug is approved, the evidence is like you need to convict someone at a murder trial: rock solid and without a shadow of a doubt," said Dr. Faden.
"But that's not a criterion the FDA could ever use and get drugs out to people in a reasonable amount of time. ... Exactly how that drug will fare once it's released is an open question."