The biggest reform in the FDA in more than a decade brings long-overdue measures to protect the public from drugs with dangerous and undisclosed or unknown side-effects.

The bill passed by Congress and expected to be signed by the president should have gone further in some areas — particularly in preventing financial conflicts — but it is a major success.

Because of the power of the pharmaceutical lobby, the reforms in the bill would have been impossible to pass in recent years. That changed after Vioxx was yanked from the market because the blockbuster arthritis drug increased the risk of heart attack and stroke.

That event led to congressional hearings in which the FDA’s own scientists accused agency officials of applying pressure to alter scientific evidence about drug safety.

The new drug safety rules will give the FDA more power to order drug companies to perform clinical trials on medication once they’re on the market. That’s an important improvement over the current system in which the agency can ask for such trials but has no way to require them.

The bill also allows the FDA to dictate what claims a company can make about its drugs. Most consumers probably believed the FDA already did that. In fact, the system was a negotiation between the government agency and pharmaceutical companies over what claims could be made.

The other keystone in the bill is a requirement that drug companies post all their clinical trial findings and final study results on the Internet. That will bring a whole new level of scrutiny.

The bill also provides incentives to drug companies. If they conduct tests to determine the effect of a drug on children, they will get an additional half-year of market exclusivity.

One big weakness in the bill is that it doesn’t do much to regulate advertising of drugs.

But its biggest shortcoming is the inability to crack down on financial conflicts in the FDA. As it stands, people on the FDA Advisory Committee who have a financial stake in a drug company can still vote on regulatory questions about that company.

Still, the FDA will soon have tools at its disposal to better safeguard and inform consumers. The real test will be whether the agency fully uses its powers for consumer benefit, or whether it succumbs to industry pressures.