Rep. Elijah E. Cummings, When it appeared on the market two years ago, the medication sounded too good to be true: a little hexagonal pill that could subdue addicts' cravings for heroin or prescription painkillers, with little risk of abuse and without creating a new long-term dependency.
For many of those who have used it, buprenorphine has lived up to its promise as a powerful new weapon against opiate addiction with major advantages over methadone, long the main medical option for addicts.
Buprenorphine can be taken at home rather than at clinics because it is less prone to abuse; it is easier to wean off of after a few months; and it leaves users less groggy, giving them the clarity of mind to start rebuilding their lives.
But buprenorphine has reached only a small fraction of those who could benefit from it, in part because of restrictions imposed by Congress when it approved use of the drug.
That might change under a bill before Congress that would lift one of its key restrictions: the 30-patient limit on prescribing the medication that applies to teaching hospitals, community health centers and one of the nation's largest managed-care groups.
The lifting of the so-called group practice cap - a restriction that lawmakers say they never intended to be so broad - could have a particularly large impact in Baltimore and other cities where many addicts tend to seek help from the clinics and hospitals most constrained by the law.
Baltimore has an estimated 40,000 heroin users, making the opiate by far the city's biggest drug problem, but the number of people receiving buprenorphine at any given time has been in the hundreds.
"It's very, very important," Dr. Peter L. Beilenson, the city's health commissioner, said of the legislation. "There's no question about it. It would not be a panacea, but it would certainly improve the situation."
The bipartisan bill would leave in place other limitations on the medication's use, most notably a restriction on the number of clients that an individual physician could treat with the drug.
And the bill would not address what substance abuse experts say are the other factors limiting its use: the drug's high cost and the reluctance of many primary care physicians to become certified to prescribe it.
Addictions specialists say lifting the limit on group practices would significantly increase buprenorphine's availability, at a time when the need for it is growing.
Although the number of heroin users nationwide has remained steady in recent years at about 800,000, the number of people abusing prescription painkillers such as OxyContin has increased sharply, to more than 4 million. (Addiction to cocaine, which is not an opiate, is not treatable with buprenorphine.)
By contrast, about 100,000 Americans have used buprenorphine since it was introduced in the United States in 2003, according to the medication's manufacturer, the British company Reckitt Benckiser.
Lifting the group practice cap "is the single thing you could do to make the most change in the shortest period of time" toward broadening access, said Shaun Thaxter, the company's vice president for marketing.
With legislative action on the horizon, the company is preparing a major marketing campaign for the medicine, which is sold as Suboxone and Subutex.
The legislation faces little opposition in Congress, where even skeptics of drug treatment acknowledge buprenorphine's worth in curbing addiction and the crime, public health problems and other social costs that come with it. But last year, the bill stalled in the House for lack of attention. It is up for review again this spring.
"We've got so many people on opiates, and just here in Baltimore so many on heroin, that you've got to find ways to expand treatment," said Rep. Elijah E. Cummings, the Baltimore Democrat who is co-sponsoring the legislation in the House with Rep. Mark E. Souder, an Indiana Republican. "And it seems like this drug is one that works for many people."
Buprenorphine, discovered as an addiction treatment in the 1970s, is a synthetic opiate that allays an addict's cravings by occupying the brain receptors that heroin and other opiates adhere to. In this, it resembles methadone, a syruplike opiate used to curb cravings that, by law, can be dispensed to most addicts only at regulated clinics. Almost 200,000 people nationwide and 6,500 in Baltimore receive methadone.
Buprenorphine - pronounced byoo-pre-NOR-feen and nicknamed "bupe" - has chemical advantages over methadone. Its effect lasts longer than methadone's, so many users need to take a pill only every two or three days. The drug's staying power helps guard against relapse - if someone takes heroin a day after taking buprenorphine, the medication will still block the high.