"A full antagonist like naltrexone is a false key that jams the ignition and the car doesn't go anywhere," he added. "Buprenorphine is the key that starts the car, but it only goes to 40 miles per hour."
It's the only partial agonist for opioid addiction, but is comparable to varenicline (Chantix), a partial agonist for smoking cessation.
Another appealing aspect of buprenorphine, addiction experts say, is the freedom and anonymity it affords. It treats addiction more like a chronic condition such as heart disease or diabetes, rather than a stigmatizing mental condition.
The efficacy of the drug has been tested in clinical trials, but addiction medicine specialists more often point to a real life example -- France. The drug was approved there in 1996, after which French authorities reported a five-fold reduction in overdose deaths and a six-fold drop in the number of active injection drug users.
Uptake in the United States has not been quite as rapid. According to Nicholas Reuter, senior public health analyst at the Substance Abuse and Mental Health Services Administration (SAMHSA), data from 2009 show that about 19,000 U.S. physicians are certified to prescribe buprenorphine, and about 640,000 patients are currently receiving treatment.
That's a clear rise from 2005, when just 4,500 doctors were certified and little more than 100,000 patients were on treatment -- not surprising since the U.S. Food and Drug Administration initially required strict limits on its use. Licensed physicians could only treat 30 patients a year.
Reuter says that was to ensure the safe distribution of the drug. The Drug Addiction Treatment Act (DATA) 2000 marked the first time addiction patients could be treated in a physician's office. Concerns arose that this would make it easier for substances to be diverted.
Others say the "methadone lobby" had a hand in crafting the regulation. Addiction experts say that buprenorphine is an economic threat to the industry of drug makers and clinics.
Mark W. Parrino, president of the American Association for the Treatment of Opioid Disorders (AATOD), which was involved in discussions in Washington on the regulation, called speculations about the methadone lobby an "urban legend."
"We don't spend a dollar on lobbying," he told MedPage Today.
Indeed, amendments to DATA 2000 have since been made, and physicians can prescribe to 100 patients at any given time, after they spend a year focused on the initial 30.
Parrino agrees that buprenorphine "is a great drug," even though it's had some challenges to wider distribution.
For instance, as part of the regulation, doctors must take an eight-hour course to obtain a license to prescribe the drug -- though, as Kolodny points out, physicians don't need a course to write opioid painkiller prescriptions.
There are also concerns about random Drug Enforcement Agency checks that some physicians feel may intimidate guests in the waiting room.
But the bigger barrier, some say, may be the lack of primary care physician desire to treat addiction patients.
"There are many myths about addicts," Kolodny said. "Physicians think they are liars and cheats, and just bad people in general. They don't realize that it can happen to anyone."
It's also not covered by all insurers, potentially leaving patients with an out-of-pocket bill in the range of about $350 to $400 per month.