Exactly which drugs approved by the FDA’s fast-track process have proved most dangerous to consumers? Given the central importance of drugs in modern medicine, you would think there would be a comprehensive tracking system at the FDA to provide this information by drug. But there isn’t.

In fact, perhaps the most famous such failure is Vioxx, which Merck finally withdrew – following years of obfuscation – after it was estimated to have killed about as many people as the U.S. military lost in the Vietnam War. Note, it was the manufacturer that pulled the drug, not the FDA.

But there are many examples. Worst Pills, Best Pills (www.worstpills.org) is a reputable, subscription-based project of the advocacy group Public Citizen that tracks safety information on nearly 2,000 drugs.

Why does the FDA permit biased company trials for safety and efficacy? Perhaps it has something to do with Congress’ underfunding of the FDA since the antiregulation period under President Ronald Reagan and then having companies fund the division that evaluates their drugs.

These practices subject patients to a double conflict of interest. First, companies test their own drugs for the public regulator, rather than having them tested independently. Then, companies pay the FDA a huge fee – $2.3 million in 2015 – to review each drug. Highly trained and skilled staff work hard to do thorough reviews. But the reviews are on the companies’ terms – their criteria, their trials, their data, their deadlines, their funded patient groups clamoring for approval, and their money.

Reviewers do turn back or turn down drug candidates. Yet 90 percent of the drugs the FDA approves are judged by independent reviewers to provide few or no clinical advantages for patients over existing drugs.

And because these new drugs are inadequately tested, the results are predictable. One in every five new drugs ends up causing enough serious harm to lead the FDA to add the most serious black box warning, or remove the drug from the market – after the harm has been done.

This risk increases to one in three when reviews are accelerated under a special (and legal) process, requiring even higher fees from drugmakers.

Do patients really want faster access to drugs that provide few or no new benefits and have substantial risks of serious harm? Do they want an FDA that largely serves the industry that funds it by approving many new minor variations to increase sales, without good testing for safety?

A few clinically superior drugs are developed each year. But accelerated reviews and low, loose FDA criteria encourage companies to develop more minor variations that will get through the approval process, rather than focus on major advances. To encourage more superior drugs, the FDA needs to require tests for real clinical advances compared to risks of harm.

We need a congressional investigation, with subpoena power, to investigate how the FDA allows manipulations of true randomized trials that understate risks of harm. We need to end a third conflict of interest that endangers patients: The same FDA group that approves drugs as “safe” is responsible for investigating evidence of harm. Only 10 percent of FDA staff are assigned to drug safety. We need an independent, well-funded watchdog for patient safety.

Most important, as a public agency charged with protecting people from unsafe drugs, the FDA needs to be funded entirely by taxpayers. Drugs are now the fourth leading cause of death in America, tied with stroke. The FDA needs to stop contributing to this problem and help reduce the number of patients exposed to risks of serious harm.

Donald Light is a widely published expert on drug policy and a professor of comparative health policy at Rowan University