Clinical Textbook of Addictive Disorders 3rd ed - R. Frances, S. Miller, A. Mack (Guilford, 2005) WW

26. Psychopharmacological Treatments 601assist in relapse prevention. Naltrexone should be administered for at least 6months, and discontinuation should be carefully planned. Naltrexone sideeffects are few, but hepatotoxicity has been reported, and hepatic functionshould be monitored before and during administration. The biggest problemwith naltrexone has been a lack of patient and clinician acceptance of thetreatment.For patients who chronically relapse to opioid dependence, the treatmentof choice is maintenance with a long-acting opioid agonist. The goal of treatmentwith any long-acting opioid is to achieve a stable dose that reduces or,ideally, eliminates illicit opioid craving and use, and facilitates the engagementof the patient in a comprehensive program that promotes substance abuse rehabilitation.Because treatment with long-acting opioids results in dependence, itis important to select patients who have a history of prolonged dependence(greater than 1 year) and demonstrate physiological dependence (positive urinetoxicology screen for opioids and evidence of opiate withdrawal prior to initiationof treatment).Methadone, the most widely used of these long-acting opioids, is effectivein decreasing psychosocial consequences and medical morbidity associated withopioid dependence. It is also an important tool in decreasing the spread ofhuman immunodeficiency virus infection in and by injection drug users. Theefficacy of methadone spans a wide range of doses, and each patient’s dose mustbe individually titrated. Methadone, 40–60 mg daily, will block opioid withdrawalsymptoms, but doses of 70–80 mg daily are more often needed to curbcraving. Generally, doses greater than 60 mg daily are associated with betterretention in treatment and less illicit opioid use (Ball & Ross, 1991).LAAM, a methadone congener that is longer acting and was thought tohave had potential advantages over methadone, has been associated with cardiacelectrophysiological complications in some patients, resulting in revisedlabeling that includes a black box warning recommending that an electrocardiogram(EKG) be performed prior to treatment, 12–14 days after initiation ofLAAM, and then periodically thereafter to rule out any alterations in the QTinterval (Orlaam Package Insert, 2001). The finding that LAAM and itsmetabolites, norLAAM and dinorLAAM exert negative chronotropic effectsand negative ionotropic responses in cardiac tissue, and the association ofLAAM with several lethal cardiac dysrhythmias (including torsades de dointes)has resulted in its no longer being a first-line treatment for opioid dependencein the United States (Expert Panel Consensus Guidelines, 2002). LAAM hasbeen removed from the market in the European Union.Buprenorphine, an opioid partial agonist, was approved for use as a treatmentfor opioid dependence in October 2002. Buprenorphine, formulated as asublingual tablet, is available as a single agent or as a combination tablet containingbuprenorphine and naloxone in a ratio of 4:1. The latter combinationproduct was designed to prevent the drug from being diverted to injection drug