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| Buprenorphine and Buprenorphine/Naloxone: New Treatment for Opiate Dependence |
| Feature Articles - Research/Scientific | |
| Saturday, 31 July 2004 | |
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Of the wide range of medical and non-medical treatments for addiction, some have proven successful while others have been — at times — barbaric and/or unsuccessful. The treatment of opiate dependence has been particularly unsuccessful over the years — it became clear that once dependence was established, opiate addicts were often intractable. Thus began the search for medications and strategies to assist the opiate addict in loosening the bonds of addiction. One solution has been the reorientation of drug treatment toward better management of the natural course of opiate addiction through the use of safer maintenance drugs. This approach views the goal of opiate treatment as both interrupting or reversing the pathological social processes that go along with heavy use of opiates and eliminating the damaging consequences of an endless cycle of withdrawal and drug craving. Medically prescribed maintenance treatment — which attempts to replace more dangerous and often illegal drugs with safer legal ones — can interrupt the progressively worsening processes of opiate addiction by permitting the opiate-dependent person to end reliance on illicit drug markets. Furthermore, it can effectively neutralize the endless cycle of craving and avoidance of withdrawal. Maintenance can permit addicts to get on with their lives even though their addiction has not been “cured” (Drucker, n.d.a).
Opiate maintenance in practice Buprenorphine and buprenorphine/naloxone are the first narcotic 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. Methadone can be dispensed only in a limited number of narcotic treatment programs. Because of this, there have not been enough addiction treatment slots for patients desiring therapy. Under this new law, medications for the treatment of opiate dependence that are Schedule III, i.e., buprenorphine and buprenorphine/naloxone, can be prescribed in a doctor’s office by specially trained physicians.2 This change is expected to provide patients greater access to needed treatment (FDA, 2002). In the meantime, the pharmaceutical company Reckitt Benckiser has placed on the market two products containing buprenorphine. The first is Subutex®, a sublingual tablet that comes in a 2mg and 8mg doses. The second is a combination of buprenorphine and naloxone. This formulation is called Suboxone® and is also taken sublingually. Suboxone® comes in two strengths. One contains 2mg of buprenorphine combined with 0.5mg naloxone, and the other contains 8mg of buprenorphine with 2mg of naloxone.
Antagonists, agonists, and partial agonists Naloxone is an opiate antagonist. This means that the medication effectively blocks the action of opiates at the receptor site. An opiate antagonist can be thought of as a “dummy key” that fits into the lock of the opiate receptor. When the dummy key is in place, the knob will not turn and the opiate receptor cannot be activated. Moreover with the dummy key in the keyhole, no other key can be inserted, and no other opiate can activate the receptor. Methadone (like morphine, heroin, and prescription opiates) is a full opiate agonist. This can be thought of as the key that opens the door completely. The more powerful the agonist and the higher the dose, the faster and the harder does the door open. When full opiate agonists are administered, the user experiences opiate effects depending on opiate type, dose, absorption, tolerance, and other variables. If an individual is exposed to enough full opiate agonist, overdose and death can be a result. Buprenorphine is a partial opiate agonist. This can be thought of the key that opens the door, but this time the safety chain is in place. The door opens some, but not all the way. Increasing the dose of partial opiate agonists produces greater effects, but this effect is limited. No matter how fast or with how much force the door is opened, the safety chain remains in place. When administered sublingually as Suboxone® and Subutex® are, the maximum effect appears to occur in the 16-32mg range. Even if doses exceed this range, the drug effect plateaus. This is referred to as the ceiling effect. The authors know of no cases of overdose death from buprenorphine alone. However, cases of death have been reported where other substances, such as benzodiazepines, have been added to buprenorphine. Most reports come from France, where buprenorphine has been on the market since 1996 (New York Times, 2003). Buprenorphine has an advantage over methadone in that overdose is not a great concern. Buprenorphine can rarely create some subjective euphoria, but not to the degree of a full agonist (NIDA, 1992). It is abusable, especially in its injectable, form but not to the extent of other opiates. However, for purposes of maintenance, buprenorphine can only be as effective as approximately 60-80mg of methadone. There exists some percentage of opiate dependent individuals who require more than 80mg of methadone to become stable and feel well. For these addicts, buprenorphine may not be effective and methadone should remain the maintenance drug of choice.
Affinity and dissociation At a buprenorphine dose of 16mg, there will be almost no binding of other opiates to the mu receptor sites. Why is this important? The following anecdote illustrates: Gina is a recovering heroin addict. She has been taking a maintenance dose of 16mg of buprenorphine. One night her boyfriend tells her that he does not want to see her anymore. Hurt and angry, Gina goes back into the neighborhood where she used to cop dope. She injects heroin into her venous system and gets no “high.” This is because the buprenorphine with its high affinity and slow dissolution is occupying the mu receptor sites. The heroin has no place to bind and cannot deliver the highly euphoric impact of a full agonist.
Abuse potential Repeated administration of buprenorphine can cause and maintain addiction. The degree of physical dependence is much less than that caused by a full agonist. Upon discontinuation, the resulting abstinence syndrome is less severe. The acute abstinence syndrome is about one-third as severe as coming off of morphine. To reduce the potential for intravenous use, the manufacturer has added naloxone to buprenorphine (Suboxone®). This medication is taken sublingually. When placed under the tongue naloxone has poor bioavailability. In other words, very little is absorbed such that no withdrawal is precipitated in an opiate-dependent client. However, if Suboxone® is ground-up and injected, the naloxone becomes highly bioavailable and will precipitate an abstinence syndrome in those who are opiate dependent. Sublingual buprenorphine has fair to good bioavailability. By using this route of administration, the maintenance patient will receive the buprenorphine and not the naloxone. This interesting formulation should decrease the abuse potential of the tablets. However, never underestimate the genius of the addict when it comes to learning how to abuse a substance. Subutex® and Suboxone® have been studied in more than 2,000 patients and have been shown to be safe and effective treatments for opiate dependence. Common side effects of both drugs include cold or flu-like symptoms, headaches, sweating, sleeping difficulties, nausea, and mood swings. These effects can last a number a weeks. The risk of serious diminished breathing may be less with buprenorphine than other opiates when used in high doses or in overdose situations (FDA, 2002).
Drug interactions, cautions, and contraindication
Counselor’s curriculum Addiction medicine specialists and recovery counselors working together have noted a medication benefit, which effectively supports the client’s learning of ways to prevent relapse to addictive behavior. Buprenorphine, as it binds to the opiate receptors, both blocks other opiates from binding and diminishes the strength and frequency of physiological opiate cravings. Often those in early opiate recovery are confronted with unexpected strong cravings that can be repeatedly triggered by simple circumstances, such as a small painful injury, an emotion, or even the time of day one used to be habitually conditioned to use drugs. Clients utilizing buprenorphine opiate replacement therapy as part of an overall treatment plan state that they experience fewer and less intense cravings. This then allows the counselor and client together to rapidly develop and practice relapse prevention skills and make lifestyle changes. With the ability to focus more on future planning, clients find they are better prepared and stronger when having to face those few unusually powerful potential relapse situations that will arrive, without suffering a full relapse to opiate use.
Cardwell C. Nuckols, PhD (
This e-mail address is being protected from spam bots, you need JavaScript enabled to view it
) is President of the Cardwell C. Nuckols & Associates, LLC, a national and international training and consulting Matthew Torrington, MD ( This e-mail address is being protected from spam bots, you need JavaScript enabled to view it ) is a clinical research physician with the Integrated Substance Abuse Programs (ISAP) at UCLA. He is the medical director of the Matrix Institute’s Narcotic Treatment Program.
Footnotes
References
Resources
American Association for the Treatment of Opioid Dependence (AATOD)
American Osteopathic Academy of Addiction Medicine (AOAAM)
American Society of Addiction Medicine (ASAM)
Center for Substance Abuse Treatment (CSAT)
National Institute on Drug Abuse (NIDA)
Substance Abuse and Mental Health Services This article is published in Counselor,The Magazine for Addiction Professionals, August 2004, v.5, n.4, pp. 52-55.              |
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