Pharmacological adjuncts in the treatment of opioid and cocaine addicts

The effects of acute oral naltrexone pretreatment on the abuse potential of intranasal methamphetamine, and the relationship between reward/punishment sensitivity and methamphetamine's effects

One potential medication for treating methamphetamine use disorder is the opioid antagonist naltrexone (NLTX). Despite encouraging preclinical findings, the results of clinical studies have been mixed. The primary aim of the current trial was to examine the effects of acute NLTX pretreatment on the subjective and reinforcing effects of intranasal methamphetamine. Nonmedical psychostimulant users completed outpatient testing sessions in which they received oral placebo (0 mg) or NLTX (50 mg) before intranasal methamphetamine (30 mg/70 kg). Primary outcome measures were peak positive subjective effects (e.g. drug 'Liking') assessed on a visual analog scale (0-100), and methamphetamine self-administration using an operant self-administration task. Participants also completed a probabilistic categorization task to assess reward and punishment learning sensitivity. Complete data were available from 13 male and 1 transgender (male-to-female) participant (age: 33.4 ± 7.6 years). Intranasal methamphetamine significantly increased subjective ratings of drug 'Liking', 'Good Effect' and 'High' from baseline (P's < 0.01), but did not significantly vary as a function of placebo or NLTX pretreatment. Similarly, methamphetamine self-administration did not vary between the placebo and NLTX pretreatment conditions. This sample did not demonstrate a significant 'bias' in learning from positive and negative outcomes (i.e. reward and punishment sensitivity), and reward/punishment sensitivity was not correlated with the effects of methamphetamine or the effects of NLTX on methamphetamine. The current study argues against the use of NLTX as a stand-alone medication for treating methamphetamine use disorder.

Polydrug abuse: a review of opioid and benzodiazepine combination use

This paper reviews studies examining the pharmacological interactions and epidemiology of the combined use of opioids and benzodiazepines (BZDs). A search of English language publications from 1970 to 2012 was conducted using PubMed and PsycINFO(®). Our search found approximately 200 articles appropriate for inclusion in this paper. While numerous reports indicate that the co-abuse of opioids and BZDs is ubiquitous around the world, the reasons for the co-abuse of these medications are not entirely clear. Though the possibility remains that opioid abusers are using BZDs therapeutically to self-medicate anxiety, mania or insomnia, the data reviewed in this paper suggest that BZD use is primarily recreational. For example, co-users report seeking BZD prescriptions for the purpose of enhancing opioid intoxication or "high," and use doses that exceed the therapeutic range. Since there are few clinical studies investigating the pharmacological interaction and abuse liability of their combined use, this hypothesis has not been extensively evaluated in clinical settings. As such, our analysis encourages further systematic investigation of BZD abuse among opioid abusers. The co-abuse of BZDs and opioids is substantial and has negative consequences for general health, overdose lethality, and treatment outcome. Physicians should address this important and underappreciated problem with more cautious prescribing practices, and increased vigilance for abusive patterns of use.

Neurogenetics of dopaminergic receptor supersensitivity in activation of brain reward circuitry and relapse: proposing "deprivation-amplification relapse therapy" (DART)

BACKGROUND AND HYPOTHESIS

It is well known that after prolonged abstinence, individuals who use their drug of choice experience a powerful euphoria that often precipitates relapse. While a biological explanation for this conundrum has remained elusive, we hypothesize that this clinically observed "supersensitivity" might be tied to genetic dopaminergic polymorphisms. Another therapeutic conundrum relates to the paradoxical finding that the dopaminergic agonist bromocriptine induces stronger activation of brain reward circuitry in individuals who carry the DRD2 A1 allele compared with DRD2 A2 allele carriers. Because carriers of the A1 allele relative to the A2 allele of the DRD2 gene have significantly lower D2 receptor density, a reduced sensitivity to dopamine agonist activity would be expected in the former. Thus, it is perplexing that with low D2 density there is an increase in reward sensitivity with the dopamine D2 agonist bromocriptine. Moreover, under chronic or long-term therapy with D2 agonists, such as bromocriptine, it has been shown in vitro that there is a proliferation of D2 receptors. One explanation for this relates to the demonstration that the A1 allele of the DRD2 gene is associated with increased striatal activity of L-amino acid decarboxylase, the final step in the biosynthesis of dopamine. This appears to be a protective mechanism against low receptor density and would favor the utilization of an amino acid neurotransmitter precursor like L-tyrosine for preferential synthesis of dopamine. This seems to lead to receptor proliferation to normal levels and results in significantly better treatment compliance only in A1 carriers.

PROPOSAL AND CONCLUSION

We propose that low D2 receptor density and polymorphisms of the D2 gene are associated with risk for relapse of substance abuse, including alcohol dependence, heroin craving, cocaine dependence, methamphetamine abuse, nicotine sensitization, and glucose craving. With this in mind, we suggest a putative physiological mechanism that may help to explain the enhanced sensitivity following intense acute dopaminergic D2 receptor activation: "denervation supersensitivity." Rats with unilateral depletions of neostriatal dopamine display increased sensitivity to dopamine agonists estimated to be 30 to 100 x in the 6-hydroxydopamine (6-OHDA) rotational model. Given that mild striatal dopamine D2 receptor proliferation occurs (20%-40%), it is difficult to explain the extent of behavioral supersensitivity by a simple increase in receptor density. Thus, the administration of dopamine D2 agonists would target D2 sensitization and attenuate relapse, especially in D2 receptor A1 allele carriers. This hypothesized mechanism is supported by clinical trials utilizing amino acid neurotransmitter precursors, enkephalinase, and catechol-O-methyltransferase (COMT) enzyme inhibition, which have resulted in attenuated relapse rates in reward deficiency syndrome (RDS) probands. If future translational research reveals that dopamine agonist therapy reduces relapse in RDS, it would support the proposed concept, which we term "deprivation-amplification relapse therapy" (DART). This term couples the mechanism for relapse, which is "deprivation-amplification," especially in DRD2 A1 allele carriers with natural D2 agonist therapy utilizing amino acid precursors and COMT and enkepalinase inhibition therapy.

Diagnosis and treatment of pathologic gambling

Pathologic gambling (PG) is an impulse control disorder characterized by recurrent and maladaptive gambling behaviors that significantly disrupt the patient's functioning in the personal, familial, or vocational spheres. Pathologic gambling is estimated to currently affect 1% to 3.4% of the adult US population and is frequently comorbid with substance abuse or dependence, attention-deficit/hyperactivity disorder (ADHD), and affective disorders. Studies show evidence for the involvement of the serotonergic, noradrenergic, and dopaminergic systems in the etiology of PG. Medication treatment studies performed in PG patients demonstrated the short-term efficacy of various serotonin reuptake inhibitors, opioid antagonists, and mood stabilizers in a subsample of adult pathologic gamblers who seek treatment. This review focuses on recent research examining the neurobiology and treatment of PG.

Double-blind naltrexone and placebo comparison study in the treatment of pathological gambling

BACKGROUND

The authors' goal was to assess the efficacy and tolerability of naltrexone in the treatment of pathologic gambling disorder.

METHODS

Eighty-three subjects who met criteria for DSM-IV pathologic gambling disorder were enrolled in a 1-week single-blind placebo lead-in followed by an 11-week double-blind naltrexone or placebo trial. Naltrexone was started at 25 mg/day and titrated upward until maximum symptom improvement or 250 mg/day was achieved. Gambling symptom change was assessed with the patient-rated Clinical Global Impression (PG-CGI-PT), clinician-rated CGI (PG-CGI-MD), and the Gambling Symptom Rating Scale (G-SAS). Side effects were monitored weekly and liver function tests biweekly.

RESULTS

Data from 45 patients were analyzed. Using random regression analysis, significant improvement was noted in all three gambling symptom measures: patient-rated Clinical Global Impression, p <.001; clinician-rated CGI, p <.001; Gambling Symptom Rating Scale, p <.019. At study end, 75% of subjects taking naltrexone were much or very much improved on both the PE-CEI PT and the PG-CGI-MD, compared with only 24% of those on placebo. Elevated liver enzymes occurred in four subjects who were taking analgesics concurrently. Nausea was common during the first week of treatment.

CONCLUSIONS

Results suggest that naltrexone is effective in reducing the symptoms of pathologic gambling. Until further studies corroborate the present findings, our report should be interpreted cautiously.

Do antidepressants have any potential to cause addiction?

Addiction/dependence is a syndrome in which the hallmark is a compulsive pattern of drug use. Most authorities do not regard antidepressants as causing addiction but this has been challenged. This debate is explored drawing on case reports and related clinical and pharmacological data. An extensive literature review identified 21 English language case reports of antidepressant addiction (DSM-IV 'substance dependence' criteria) published since 1963. Sixteen involved tranylcypromine or amineptine and may reflect their dopaminergic and stimulant properties. Subject characteristics included male sex (14/21), personality problems (10/21) and prior substance misuse (14/21). Withdrawal or discontinuation symptoms have long been recognized with antidepressants but other features of addiction such as tolerance and compulsive use are exceptionally rare. Common clinical problems are patients taking subtherapeutic dosages and prematurely stopping antidepressants. The pharmacodynamic profiles of most antidepressants and the absence of acute 'desirable' effects make addiction theoretically unlikely. It is concluded that, with the exception of tranylcypromine and amineptine, antidepressants do not have a clinically significant liability to cause addiction. Tranylcypromine and amineptine should be avoided in those with a history of substance misuse. Patients prescribed other antidepressants should be told that they are not addictive.

Opioid and benzodiazepine tolerance and dependence: application of theory to critical care practice

Critical care clinicians frequently manage patient pain and agitation and promote ventilator stability through use of opioids and benzodiazepines. Often, doses of these drugs must be increased considerably over time as they lose their effectiveness-an indication of drug tolerance. Furthermore, patients can experience negative physiologic responses to withdrawal of these drugs-an indication of drug dependence. Withdrawal symptoms due to abrupt discontinuation of drug therapy can be profound and dangerous. It is important that clinicians understand the mechanisms of drug therapies and their potential negative sequelae. The purpose of this article is to present physiologic theories of opioid and benzodiazepine actions, as well as drug tolerance and dependence, as a basis of knowledge for clinical practice. A clinical scenario of an intensive care unit patient is presented, and a care plan is offered, to provide guidance to practitioners who care for patients experiencing the consequences of long-term opioid and benzodiazepine use.

Program administrator and medical staff attitudes toward six hypothetical medications for substance abuse treatment

There is growing interest in a number of medications with proven clinical efficacy or potential for treating substance abuse. At the same time, many treatment programs make little, if any, use of pharmacotherapy. The reasons for this circumstance are not clear. An exploratory survey using focus groups and telephone interviews with medical personnel and administrators from 38 programs and three professional associations suggests that program staff perceive a variety of drawbacks to pharmacotherapy, which may help account for the lack of more widespread use of this treatment modality.

Relapse prevention: an emerging technology for promoting long-term drug abstinence

This article reviews relapse prevention strategies that can be applied after primary drug treatment. To sustain their own recovery, ex-addicts must learn a program of self-management to cope with drug cravings and social pressures to use drugs, become integrated into a new social network, learn to find pleasure in drug-free activities, and find new ways of responding to emotional stress and physical pain. While additional research is needed to identify the very best methods, there is now sufficient evaluation data to argue that practitioners should incorporate this approach as an integral part of their treatment services.

The phenomenon of abusable psychotropic use among North American youth

Abusable psychotropic use can, and does, affect all North American youth, either directly or indirectly, regardless of age, gender, culture, ethnic background, education, race, or socioeconomic status. Over the last decade, the morbidity and mortality associated with abusable psychotropic use among youth have become staggering. A current overview of the phenomenon of abusable psychotropic use among youth in North America, including the use of alcohol, cannabis, cocaine, LSD, nicotine, and polyabusable psychotropic use, is presented with attention to the expanding role of clinical pharmacologists in relation to both prevention and treatment. The Mega Interactive Model of Abusable Psychotropic Use Among Youth is presented as a heuristic device to assist clinical pharmacologists, and other health care providers, in addressing the multifactorial interactive aspects of this complex phenomenon as observed in the pediatric age group. In this regard, attention is given to the interaction of the Abusable Psychotropic Dimension, including the Abusable Psychotropic Variables (e.g., pharmacokinetics, abuse potential) and Pattern of Use Variables (e.g., social use, abuse, compulsive use), with the Young Person, Societal, and Time Dimensions.

Treating crack cocaine dependence: the critical role of relapse prevention

In order to adequately address the treatment needs of crack cocaine dependent persons, a multidimensional approach to relapse prevention must be utilized. The value of a biopsychosocial model of crack addiction and the concept of phases of recovery in providing a rationale for the recommended approach to relapse prevention are emphasized. Research findings on the determinants of relapse for crack dependent patients and the psychosocial characteristics of the crack dependent individual justify the utility of certain relapse prevention strategies. Specifically, an approach to relapse is advocated that includes the provision of pharmacological adjuncts, psychoeducation on the multideterminants of relapse, and psychotherapy that attempts to remediate underlying psychological problems that are typically found in crack dependent patients.

Treating crack cocaine dependence: the critical role of relapse prevention

In order to adequately address the treatment needs of crack cocaine dependent persons, a multidimensional approach to relapse prevention must be utilized. The value of a biopsychosocial model of crack addiction and the concept of phases of recovery in providing a rationale for the recommended approach to relapse prevention are emphasized. Research findings on the determinants of relapse for crack dependent patients and the psychosocial characteristics of the crack dependent individual justify the utility of certain relapse prevention strategies. Specifically, an approach to relapse is advocated that includes the provision of pharmacological adjuncts, psychoeducation on the multideterminants of relapse, and psychotherapy that attempts to remediate underlying psychological problems that are typically found in crack dependent patients.