Methadone maintenance and narcotic blocking drugs

Drugs which specifically antagonize certain of the actions of opioids are reviewed. These antagonists include nalorphine, levallorphan, naloxone, naltrexone, and cyclazocine. Programs involving antagonist treatment are discussed.

Methadone maintenance and narcotic blocking drugs. Appendix

The research history of norcodeine as a narcotic blocking drug is presented. Because of the limitations found for norcodeine usage, naloxone, cyclazocine, and naltrexone have recently received attention, and the results of research with them are detailed.

Subjects' rights, freedom of inquiry, and the future of research in the addictions

Since the recent passage of regulations concerning subjects' rights and freedom on inquiry, opposition by the public and others to some areas of research in the addictions has prevented its implementation or continuation. Research investigators in the biomedical and behavioral sciences have been placed in the position of defending their work in an adversary climate. The author points out the importance of transmitting to the public, the scientific community, and legislators the investigators' concern that "subjects' rights" not be viewed only in a legalistic context, but also in the context of not harming the patient.

Effects of legal pressure on prognosis for treatment of drug dependence

The authors found that four measures of legal pressure were either unrelated or negatively related to retention and outcome in five drug abuse treatment modalities. This suggests that nonvolunteer clients are likely to be insufficiently motivated to benefit fully from treatment and their presence may adversely affect staff morale and prognosis of volunteer clients. The authors recommend that legal pressure not be used as a basis for assigning applicants to treatment modalities and suggest that treatment outcome might be improved by procedures that 1) deal clinically with motivational differences between volunteers and nonvolunteers, 2) establish stricter motivational criteria for admitting nonvolunteers, or 3) encourage enforcement of existing sanctions against violations of stipulations to treatment.

Naloxone

Narcotic analgesics and related drugs act as agonists on several receptors that are responsible for their effects on pain perception, mood and feeling state, and respiration, as well as other pharmacologic actions. Naloxone is the first discovered antagonist that is devoid of agonistic activity and appears to be a competitive antagonist at several receptors. The ability of naloxone to displace or prevent the binding of agonistic narcotics is partly responsible for its antagonistic effects. The ability of naloxone to rectify narcotic-depressed homeostats and precipitate abstinence is also related to its antagonistic activity. Certain cautions and principles apply in the use of naloxone in treating narcotic overdose, reversing surgical analgesia, and the treatment of neonates and children. Unapproved uses of naloxine include reversing the psychotomimetic effects of certain agonists-antagonists, terminating narcotic-induced convulsions and coma, reversing non-narcotic depression, diagnosing physical dependence, and treating narcotic addicts.

Narcotic antagonists. Treatment tool for addiction

Narcotic antagonists have recently gained attention through research aimed at evaluating both biochemical effects and treatment potential for opiate addiction. Narcotic antagonists are a classification of drugs which block the euphoric (and all other) effects of opiates. Naltrexone is the most promising narcotic antagonist based on ability to produce blockade, length of duration, and relative absence of side effects. The narcotic antagonists offer an adjunctive or alternative method of treatment for opiate addicts based on Wikler's biobehavioral theory of conditioned abstinence. Narcotic antagonists are presently being investigated at seven research centers throughout the United States and may be available for clinical use in the future.

Clinical trial in post-addicts with oxilorphan (levo-BC-2605): a new narcotic antagonist

Oxilorphan (levo-BC-2605) is a new, long-acting, narcotic antagonist that has agonist properties. Twenty-one (21) heroin addicts in Los Angeles were detoxified and given at least one oral dose of oxilorphan. Only three (14.3%) patients took daily doses for 14 days, which was the maximal time allowed for oxilorphan administration in this study. The remainder discontinued oxilorphan because of subjective side effects or for unknown reasons. Side effects most responsible for dropouts were dysphoria, insomnia, weakness, hallucinations, nausea, drowsiness and anorexia. Oxilorphan provided 24-hour protection with a single, oral dose, but subjective side effects encountered during inductiolinical trials with oxilorphan should be attempted with other addict populations to fully determine its potential therapeutic value.

A behavioral paradigm for the evaluation of narcotic antagonists

We have developed an experimental paradigm for the behavioral evaluation of narcotic antagonists. The study specifically examined the heroin-seeking behavior of hard-core narcotic addicts on a research ward under blocked and unblocked conditions. Each patient served as his own control. A long-term follow-up program in the community, with aftercare services, was utilized to determine the relationship between behavior observed on the research ward and behavior that occurred in the community. While preliminary one-month follow-up data offered some cause for an optimistic view of narcotic antagonist treatment, behavioral data observed on the research ward raised serious doubts about the possibility of extinguishing heroin self-administration with antagonists. The behavioral data were not consistent with laboratory descriptions of extinction. Rather, the data suggested that narcotic antagonist programs should emphasize the development of contingencies for the reinforcement of narcotic antagonist self-administration to ensure an opiate-free state, instead of focusing on an extinction approach.

Behavioral and social effects of heroin self-administration and withdrawal

Behavioral and social reactions to intravenously administered heroin were studied during a 33-day experimental addiction cycle. Three groups of four subject volunteers were allowed to self-administer heroin for a ten-day period as part of a longer study of oplate antagonists. Data relevant to sleep patterns, energy expenditure, social interaction, and other observable behaviors were collected during hourly observations. Comparison of behavioral differences before and after drug administration indicated few significant acute reactions. Reactions to long-term heroin self-administration were most pronounced in the areas of sleep behavior and social interaction. Subjects tended to sleep less, especially during the initial period of acquisition, and to withdraw more from social contact. No changes were noted in energy expenditure during waking hours. The results were interpreted in terms of physiological tolerance, central nervous system arousal, and sleep deprivation.

Testing of drug delivery systems for use in the treatment of narcotic addiction

The evaluation of the drug release characteristic of four naltrexone delivery systems has been carried out together with the development of analytical techniques and an investigation of the metabolic profile of naltrexone. Pharmacologic evaluation of the four delivery systems in the mouse indicated significant analgesic antagonism for a period of from 16-22 days. Further evaluation of one of these systems by measurement of the rate of excretion of radioactivity after administration of radiolabelled naltrexone in the delivery system confirmed that significant release occurs for a time period of about 15 days. Electron capture gas-liquid chromatographic assays for naltrexone and naloxone in plasma or urine have been developed that yield linear calibration curves and are sensitive to one ng/ml. Studies on naltrexone disposition indicate that (a) binding to plasma proteins in several species varies from 20-26%, (b) distribution of drug from blood is extremely rapid and extensive, (c) beta-naltrexol is a major metabolite of naltrexone in man, monkey and guinea pig among six species studies, whereas alpha-naltrexol is a minor metabolite in the monkey and guinea pig only, and (d) metabolic reduction of naltrexone occurs in the 100,000 x g supernatant of guinea pig liver. Pharmacokinetic studies of naltrexone in the dog and monkey indicate that the drug is rapidly distributed and eliminated, has a very large apparent volume of distribution and a total body clearance greater than the rate of liver blood flow.

Analysis and modification of opiate reinforcement

The authors describe a research protocol for the evaluation of narcotic antagonists which examines the heroin-seeking behavior of hard-core heroin addicts on a research ward under blocked and unblocked conditions. Each patient served as his own control. This paper serves as an introduction to a series of papers which follow dealing with behavioral, psychiatric, and aftercare results. It describes detailed methods and preliminary results for the first 21 subjects admitted to the study. More specific results are reported in the papers that follow.

Psychopathology, craving, and mood during heroin acquisition: an experimental study

Six detoxified addict volunteers were allowed to self-administer intravenous heroin on an essentially self-determined schedule. Two periods of heroin acquisition were compared: an unmodified cycle in which patients could become intoxicated and a later cycle in which the effects of heroin were blocked with a narcotic antagonist. In the unblocked condition, patients initially experienced an increase in positive mood, but with chronic administration there was a significant rise in psychopathology and the development of a generalized dysphoric state. Similar changes did not occur when the same patients took heroin while blocked with a narcotic antagonist. Drug craving rose dramatically when "unblocked" heroin was available, but gradually fell during methadone detoxification. Following treatment with a narcotic antagonist, the presence of heroin failed to elicit any sustained rise in craving and drug taking was dramatically reduced.

Opiate antagonists and the modification of heroin self-administration behavior in man: an experimental study

The heroin self-administration behavior of 8 inpatient heroin addicts was examined for 10 days under blocked (i.e., following ingestion of narcotic antagonists--naloxone or naltrexone) and unblocked (no antagonist) conditions. In the unblocked state, subjects injected all the available heroin, but they ceased heroin use almost completely following antagonist administration. Possible explanations for these results are discussed along with their implications for treatment.

Aftercare on narcotic antagonists: prospects and problems

This study examines the problems and prospects of aftercare of the multiple treatment failure opiate addict who is being treated with narcotic antagonists (primarily naltrexone). At the time of this paper, 21 patients had been admitted to the Drug Addiction Research Project at McLean Hospital, with a retention rate of 42%. "Completers," "noncompleters," and "dropouts" could not be differentiated on the basis of demographic or psychiatric variables, thus making it impossible to define the population most suited for antagonist treatment. The degree of carry-over into the first month in the community, for those who successfully completed the inpatient segment of the program, disappeared over time. The nonreinforcing (lack of euphoric effect) properties of the antagonists and the resultant high level of motivation necessary for the continuation of its use by the patient make this form of treatment suitable for only a small percentage of the "hard core" addict population.

Some pharmacological aspects of drug dependence

The self-administration of drugs to achieve altered states of consciousness is recognized as normal human behaviour. Community attitudes towards drug use vary according to the drug and often bear little relationship to the known pharmacological and toxicological effects of the drug. For an objective assessment of the potential dangers associated with drug use, a distinction is made between drug use and drug abuse. It is stressed that the progression from drug use to drug abuse involves social and psychological factors in addition to the pharmacological factors which are outlined in this paper. The sequential development of drug dependency is described under the headings: Induction; continued consumption; compulsive consumption; withdrawal; abstinence; reinduction. Man uses psychotropic drugs because he finds the effects rewarding. Some experimental models to explore the neurophysiological basis of the reward are described. Experiments employing inhibitors of protein synthesis suggest that the phenomena of tolerance and physical dependence involve the synthesis of new protein. It has been suggested that the new protein might be new receptor molecules for the drug or neurotransmitter substances. These new receptors might constitute a "drug memory" and provide a possible explanation for high relapse rate of drug dependent subjects. A pharmacological basis for the methadone maintenance programme of management of narcotic dependent subjects is briefly outlined.

Pharmacological approaches to the treatment of morphine-type dependence

Of the two pharmacologically different possibilities of interfering with the processes of either tolerance or dependence of the morphine type, the so-called maintenance method commonly using methadone is predominantly a matter of tolerance, whereas the blockade with specific opiate antagonists such as cyclazocine intervenes in processes underlying dependence and withdrawal. The experimental evidence for these mechanisms is described.

Lomotil ingestions in children

Although the incidence of adverse reactions is relatively low in adults, Lomotil may result in serious toxicity in children. Early effects are often due to the atropine present in the compound, while the narcotic-like actions of diphenoxylate HCI tend to occur later. Respiratory depression is the most threatening reaction and should be treated with naloxone.

Propranolol in the treatment of opiate dependence -- a controlled study

Two doublebling placebo controlled experiments designed to elucidate the alleged narcotic blocking effect of propranolol wer performed. In the first experiment, propranolol 40 mg or 20 mg was given together with methadone during the acute withdrawal phase of opiate addiction. The second experiment assessed whether 10 mg of propranolol, given 2 hrs before 30 mg of morphine i.v., reduced the euphoric effects of the latter drug. In none of the experiments could narcotic blocking effects be detected. The group receiving 40 mg propranolol during detoxification exhibited the highest proportion of patients staying for the whole prescribed detoxification period.