Thursday, September 15, 2005
First, I summarize some point from his article, and a few others, then add a few bits of my own.
Dr. Clark provides us with some historical background in his article, Office-Based Practice and Opioid-Use Disorders (H. Westley Clark, M.D., J.D., M.P.H.: NEJM, Volume 349:928-930, September 4, 2003)
In the case of Webb v. United States, the U.S. Supreme Court ruled that the 1914 Harrison Narcotic Drug Act made it illegal for physicians to prescribe narcotics for the purpose of keeping a patient "comfortable by maintaining his customary use." For more than 80 years, it remained illegal in the United States for physicians to prescribe opioid medications for the treatment of opioid dependence. [...]
The Harrison Narcotic Drug Act and decisions such as Webb v. United States essentially gave the following message to physicians: "Treat an addict; go to jail." Physicians consequently were reluctant to address the medical needs of those with opioid-use problems. [...]
On October 17, 2000, the Drug Addiction Treatment Act of 2000 was signed into law in the United States. This act allows Schedule III, IV, or V narcotic medications that have been approved by the Food and Drug Administration (FDA) for the treatment of narcotic-use disorders to be administered for either medically supervised tapering (detoxification) or long-term maintenance. On October 8, 2002, the FDA approved the use of buprenorphine (see Figure) and of buprenorphine in combination with naloxone — both Schedule III drugs — for either detoxification or maintenance.
Dr. Clark spares us the additional political dimension, that of the "War on Drugs." Those interested in that orthogonal may wish to review the commentary in the Blogosphere at Pornographical Physics and INDC Journal.
Those interested in yet another dimension may wish to see what the artistically inclined have to say about the subject.
Collapsing back to the Flatland of neurochemistry, let's review what is known about buprenorphine. It acts on the mu (µ) opioid receptors in complex way. It is a mixed agonist-antagonist (or partial agnonist), meaning that it partly stimulates the receptors, but prevents them from receiving further stimulation.
Buprenorphine is available in three formulations: Buprenex ®, is an injectable form of buprenorphine hydochloride that is suitable for treatment of acute pain in persons who are not opiate dependent; Subutex ®, a tablet for sublingual usage, contains buprenorphine hydochloride as the only active ingredient; Suboxone ®, also a sublingual tablet, contains two ingredients: buprenorphine HCl and naloxone HCl. (1, 2) For the purposes of this article, I will refer to Subutex and Suboxone collectively by the informal term, "Bup," which is short for buprenorphine.
Subutex and Suboxone are manufactured by Reckitt Benckiser Pharmaceuticals (whose main claim to fame is that they are the World's #1 producer of household cleaning chemicals.) What is the rationale for including Naloxone in the Suboxone formulation? Naloxone is a mu opiate antagonist. It is not active when taken by mouth, so it does nothing if the drug is used as intended. However, if someone attempts to abuse it via injection, the naloxone blocks the opiate receptors, preventing the buprenorphine from acting. If that person happens to be opiate dependent, it puts them into abrupt withdrawal. Few people do that more than once.
Subutex and Suboxone were developed specifically under the aegis of the National Institute on Drug Abuse's Medication Development Division; this involved collaboration between NIDA, the FDA, and private industry. It was developed in response to some practical difficulties that arose with the use of methadone. Every once in a while, good things happen when people sit down and talk to each other. As the FDA puts it:
Subutex and Suboxone are the first narcotic [usage note - ed.] drugs available for the treatment of opiate dependence that can be prescribed in an office setting under the Drug Addiction Treatment Act (DATA) of 2000. Until recently, opiate dependence treatments in Schedule II, like methadone, could be dispensed in a very limited number of clinics that specialize in addiction treatment. As a consequence, there have not been enough addiction treatment centers to accommodate all patients desiring therapy. Under this new law, medications for the treatment of opiate dependence that are subject to less restrictive controls than those of Schedule II can be prescribed in a doctor's office by specially trained physicians. This change is expected to provide patients greater access to needed treatment.Indeed, Bup has been shown to be helpful for persons with heroin dependence. The NEJM article summarizing the seminal study is this one: Office-Based Treatment of Opiate Addiction with a Sublingual-Tablet Formulation of Buprenorphine and Naloxone. The results actually were underwhelming, at least at first glance:
The proportion of urine samples that were negative for opiates was greater in the combined-treatment and buprenorphine groups (17.8 percent and 20.7 percent, respectively) than in the placebo group (5.8 percent, P<0.001 for both comparisons); the active-treatment groups also reported less opiate craving (P<0.001 for both comparisons with placebo). Rates of adverse events were similar in the active-treatment and placebo groups. During the open-label phase, the percentage of urine samples negative for opiates ranged from 35.2 percent to 67.4 percent. Results from the open-label follow-up study indicated that the combined treatment was safe and well tolerated.So persons treated with placebo stayed straight about 5% of the time; whereas those who were treated were successful about 20% of the time. Like I said, that may not seem impressive. But when you consider the awful consequences of heroin abuse, any improvement in the rate of success is welcome. Note, however, that Bup is not limited to use in treatment of heroin dependence. It can be used for treatment of dependence or abuse of any opiate. Furthermore, it can be used in three ways. It can be used to detoxify patients, i.e., taper them entirely off the use of an opiate. It can be used for long-term maintenance of opiate abusers. Also, it can be used for long-term treatment of chronic pain, even if the patient was not actually abusing whatever opiate they were treated with initially.
Over the next few days, I plan to go into more detail about these various uses of bup. In the meantime, if you find yourself craving more medical writing, check out the 51st Grand Rounds at Sneezing Po.
usage note: the term narcotic is actually a legal term, under law that defines certain drugs as drugs of abuse; it is not really a medical term. The term narcotic referes to a pharmacologically diverse group of drugs, including heroin, cocaine, and cannabis. The more precise term for morphine-like drugs is opiate.
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Some adverse effects go away after afew days or weeks. But it is sedating, and that effect might improve but not disappear entirely.