Buprenorphine was identified as a viable option for maintenance treatment of individuals addicted to opioids more than 20 years ago.
7 Research during the past two decades has documented the safety and effectiveness of buprenorphine for this indication, and the enactment of DATA 2000 has now enabled physicians in the United States to offer specifically improved forms of buprenorphine for treating patients with opioid addiction.
7 In this regard, it was recently reported that buprenorphine and methadone had similar safety and side effect profiles, and there was no evidence that buprenorphine was selectively associated with abnormal liver function compared with methadone.
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Buprenorphine has unique pharmacologic properties that make it an effective and well-tolerated addition to available pharmacologic treatment modalities for addiction. Repeated administration of drugs that activate opiate receptors (opioid agonists, eg, morphine, heroin [diacetylmorphine], and methadone) produces physical dependence and tolerance. Physical dependence is manifested as a characteristic set of withdrawal signs and symptoms that emerge upon reduction or complete cessation of using a drug.
Addiction is a behavioral syndrome characterized by repeated compulsive seeking or use of a substance despite adverse social, psychological, or physical consequences either singly or in combination. Opioid addiction often, but not always, is accompanied by tolerance, physical dependence, and opioid withdrawal syndromes (Table). Drugs that bind to, but do not activate, opioid receptors are opioid antagonists (eg, naltrexone and naloxone). Opioid partial agonists are drugs that activate receptors, but to a lesser degree than full agonists. Increasing the dose of a partial agonist does not produce as strong an effect as does increasing that of a full agonist. Pharmacologic effects (including respiratory depression) of a partial agonist reach a ceiling at moderate doses and do not increase significantly from that point, even with higher doses.
The partial agonist properties of buprenorphine make it a safe and effective option for treatment of patients for opioid addiction. Buprenorphine has sufficient agonist properties such that when it is administered to individuals who are not opioid dependent but are familiar with the effects of opioids, they experience subjectively positive opioid effects. These subjective effects aid in maintaining compliance with buprenorphine dosing in patients who are opioid dependent. Buprenorphine also occupies opioid receptors with strong affinity and thus blocks opioid full agonists from exerting effects. Buprenorphine dissociates from opioid receptors at a slow rate, thereby enabling daily or even less frequent dosing (eg, three times per week).
Although buprenorphine can be misused (consistent with agonist action at opioid receptors), its abuse potential is lower in comparison with a full opioid agonist. A new formulation containing buprenorphine in combination with naloxone has been developed to decrease the potential for abuse via the injection route. Physicians who prescribe or dispense buprenorhine or the buprenorphine and naloxone combination should monitor for diversion. Because of the potential for serious drug-drug interaction, buprenorphine must be used with caution with certain other types of medications, particularly benzodiazepines, other sedative drugs, opioid agonists and antagonists, and drugs metabolized by cytochrome P450 3A4.