Good medicine involves a sometimes precarious balance for which there is no textbook guide. With every course of treatment they prescribe, physicians have to weigh potential benefits against the possibility of harm. The introduction of buprenorphine treatment in France - and elsewhere - raised that issue: how to properly balance widespread access to the drug, getting as many addicts as possible into treatment, with adequate control.

Introducing Subutex
Health officials in France introduced Subutex a year after methadone, less to try to cure the country's estimated 150,000 addicts than to reduce the associated dangers of intravenous drug use - principally, the spread of HIV. At the time, up to 40 percent of addicts using needles were thought to be infected.

Officials believed it would be impossible to stem HIV by treating addicts with methadone alone; as in the United States, methadone was administered initially under tight supervision only at specialized centers. There were hardly enough of the centers. And methadone carried a much higher risk of fatal overdose.

In giving general physicians the right to prescribe buprenorphine from their offices, the government did not require training or certification and placed no limit on the number of patients doctors could treat. The United States, by contrast, requires minimal training - eight hours - and limits a doctor's buprenorphine practice to 100 patients.

In France, no central registry tracked prescriptions, and tablets were dispensed in take-home doses like antibiotics or antihistamines.

By the late 1990s, 65,000 French patients were taking Subutex. By 2005, the number had climbed to 90,000, nine times more than the total taking methadone, according to researchers. Schering-Plough estimates that 85,000 people are being treated now.

"We needed to urgently treat heroin addicts," said Nathalie Arens-Richard of the French Health Products Safety Agency, which, like the U.S. Food and Drug Administration, monitors the safety and misuse of medicines. "We didn't know what the problems with the treatment were going to be."

Over the years, concerns over misuse and the high costs for the government led to adjustments in how Subutex is dispensed. In 1999, France tightened the take-home limit. In 2004, the government further clamped down to counter a black market trade that France was, in effect, subsidizing. Subutex had become one of the top drugs paid for by the government.

Although the 2004 change prevented patients from submitting multiple prescriptions for reimbursement, they still could fill multiple prescriptions as long as they paid for the drug themselves. Critics suggested the government had acted not because of health or social costs but rather budget concerns.

Last year, the French health ministry rejected a proposal to reclassify the drug in a way that would result in tougher penalties for peddling it.

Michel Mallaret, president of the National Commission on Narcotics and Psychotropic Substances, recognizes the trafficking problem but sees benefits in keeping the drug widely available.

"We have to be very cautious if we have more control," he said. "The great risk is to see AIDS increase again, or injection, or overdose."

French officials have also discussed using Suboxone, which the European Union approved for marketing in 2006. But the government has been weighing whether that makes sense, given the possible higher cost of Suboxone and doubts about the effectiveness of its injection deterrent.

Sufficient rush
Pierre Chappard is typical of Subutex users who prefer to inject it. The former heroin addict has been receiving the drug by prescription for 10 years and is dependent on it. Twice he tried to quit but, for now at least, has given up on giving it up.

Four times a day, the one-time high school math teacher shoots up the drug and feels a pleasant rush. Chappard, 35, first used Subutex the year it was introduced, crushing it and mixing it in an injectable solution. It didn't give him the same flash as heroin, but it sufficed. Best of all, it was legal. You could get it from a regular doctor, and France's health care system would pay the cost.

Chappard is among the many addicts who say they can't, or won't, give up the ritual of injection. "The people who have injected heroin, we won't go to a Subutex pill," he said. "To just stop injecting and start taking a pill, it's too difficult."

But he admits to a motive beyond that: "You're injecting because you want more effect. The Subutex gives me a little bit of high, but I'm normal."

He still shoots heroin a few times a year but said he doesn't share needles. He filters his Subutex to remove large particles that could make injection dangerous.