WASHINGTON - The Senate overwhelmingly approved a drug-safety bill yesterday, doubling the number of government scientists assigned to ferret out risky side effects in medicines already on the market.

The bill also would create a computerized network to scan medical insurance and pharmacy records for signs of trouble with new drugs, and significantly expand the Food and Drug Administration's power to require drugmakers to reduce risks.

"This is unquestionably the biggest change in the FDA's regulatory authority in a very long time," former FDA Commissioner Mark McClellan said.

The Senate bill was drafted in response to highly publicized safety lapses, including the belated withdrawals of the pain reliever Vioxx and the diabetes drug Rezulin, as well as the FDA's tardy warning about the suicide risks of antidepressants. A tougher bill is expected to emerge from the House in coming weeks.

The Senate bill also responds to consumer complaints about misleading drug advertising, by setting up a voluntary program through which the FDA would review television commercials before they are aired.

After a week of contentious debate and an unsuccessful effort to add a provision to let consumers buy drugs from foreign suppliers, the Senate approved the bill, 93-1. All Philadelphia-area senators voted yes. Sen. Bernard Sanders (I., Vt.), a strong critic of the drug industry, voted no. The import amendment was opposed by the Bush administration and could have stalled the safety overhaul.

The House is expected to begin writing its own version of the legislation soon. Its approach is expected to be tougher on industry, but senior House lawmakers have praised the Senate's basic approach. Senior members of the House say their main goal is to get a bill to President Bush by the summer.

The safety provisions are part of a larger bill reauthorizing industry user fees that now provide about half of the funding for drug review and approval. Some consumer groups and lawmakers oppose funding the FDA through industry fees, saying that creates a conflict of interest.

Nonetheless, the funding bill is considered "must-pass" because if Congress fails to act by the summer, the FDA could be forced to notify hundreds of senior scientists, doctors and statisticians - whose skills are in demand in private industry - that their jobs could be at risk.

The Senate bill, drafted by Sens. Edward M. Kennedy (D., Mass.) and Michael B. Enzi (R., Wyo.), would more than double the size of the FDA's safety office, which now has a staff of about 90. The cost of that expansion would be covered by user fees, which would rise from a total of more than $300 million this year to $539 million in 2008 and $916 million in 2012, according to Senate staffers.

Kennedy said the bill "greatly improves the way the FDA oversees the safety of drugs. . . . When patients are in danger, the FDA should not have to wait to get legal opinions . . . to protect health."

With nearly half of adults regularly taking some kind of prescription medication, the risk of dangerous side effects has become a much bigger concern in recent years.

Currently, new drugs are tested on no more than a few thousand people before approval, and rare side effects might not emerge until many more patients have used a medication. Some prominent medical experts think all new drugs should be considered experimental for at least two or three years after approval.

The computerized system outlined in the bill would provide a way to keep closer tabs on newly approved drugs. That would be a major step forward for the FDA, which now relies on an antiquated system based on anecdotal reports from doctors, and picks up only a small fraction of adverse reactions.

"The legislation allows for routine, active safety monitoring using large linked databases," Enzi explained. The network would be designed to scan millions of records in billing files from government health-care programs and private insurers. Patients' identities would be protected.