About one million Americans are dependent on heroin, prescription painkillers and other opioids, and the vast majority does not receive treatment. Combined with psychological counseling, opiate substitutes that prevent withdrawal are among the most effective treatments for these addictions. Until now, only two drugs--methadone and levo-alpha-acetyl methadol (LAAM ) were available, and only licensed treatment clinics were authorized to dispense them. Many addicts normally avoid opiate treatment programs (OTPs) because of the inconvenience, perceived stigma and because of limited treatment slots. The Food and Drug Administration (FDA) has approved buprenorphine, a new drug that could reshape opiate addiction treatment in the United States. This treatment could make pharmacotherapy available and attractive to patients who previously shunned it. Psychologists helped develop this drug and will provide key services to patients treated with it. Like heroin, methadone and many prescription painkillers, buprenorphine acts on the brain's mu-opioid receptors to cause analgesia, euphoria and other effects. But unlike them, it is a partial agonist--a drug that has mechanisms of action that are similar to pure agonists, such as heroin, but with less potency. Even when it occupies almost all of the brain's mu-opioid receptors, buprenorphine has only about 40 percent of the effect that heroin has. Another pharmacological factor that makes buprenorphine well suited to addiction treatment is its high affinity for the mu-opioid receptor. Even after it's been removed from the blood by elimination and metabolism, buprenorphine stays firmly attached to the brain's receptors, blocking the effect of other drugs with lower affinities. That means that opiate-dependent individuals who take buprenorphine won't get any additional kick from using other opiates, such as heroin. Buprenorphine's stickiness has another advantage, because it clings to the receptor long after it has been administered, it can make the detoxification process easier. |
