NEW YORK (MainStreet) — New drugs that are fast-tracked through the FDA approval process are more likely than those drugs that took the slow route to get black box warnings, which alert prescribers and patients about the most serious drug warnings required by the FDA, and to be withdrawn from the market.

Patients want access to new drugs, and pharmaceutical manufacturers are happy to help. However, newer doesn't always mean better for patients, except in the case of break-through drugs. Full risks of drugs are sometimes not known for as many as 30 years. But new drugs can mean more money for the manufacturer.

Researchers from Cambridge Health Alliance Harvard Medical School, Boston Medical Center (BMC)/Boston University School of Medicine, City University of New York School of Public Health, and Public Citizen found that there was a one in three chance that newer drugs will receive either a black box warning or be withdrawn from the market due to safety reasons within 25 years of getting FDA approval.

The researchers reviewed a 35-year period, comparing the number of black box warnings and rates of market withdrawal for drugs that were released before and after the passage of the Prescription Drug User Fee Act (PDUFA), which allows manufacturers to get drug approvals fast tracked through the FDA for a fee and continue studying them after approval. They found rates increased from 21.2% to 26.7% per 100 drugs from the year at which point the FDA approval process changed, dropping the time to approval for all drugs from an average of 34 months to 16 months.

While a 5.5% difference may not seem like that much, Cassie Frank, a physician at Cambridge Health Alliance, an instructor in medicine at Harvard Medical School, and lead author of the study published in the journal Health Affairs, says that "[b]y the time many drugs receive serious safety warnings, millions of Americans have already been exposed to their side effects, which can sometimes be fatal."

Study co-author Dr. Sidney Wolfe, founder of Public Citizen's Health Research Group and author of Worst Pills, Best Pills said at a press conference on Monday that many of these drugs were "me, too" drugs, meaning that they were similar to drugs with known safety profiles, because they had been on the market for years.

Frank opts to prescribe older drugs when they are available. Wolfe said that "there's no reason to prescribe a drug that is not a break-through drug." He recommends not taking a drug until it's been on the market for at least seven years.

"The FDA's resources for reviewing drugs have increased dramatically since the passage of PDUFA, amounting to $760 million this fiscal year from pharmaceutical companies, about two-thirds of the agency's drug review budget," says Wolfe.

For drugs that have clear benefits over other drugs in their class, this fast tracking may have come with some relief to patients in need. However, during the period studied, 32 of the drugs that have been withdrawn from the market for safety reasons did not have clearly unique benefits when they were approved but each had unique risks that led to their withdrawal.

--Written by S.Z. Berg for MainStreet