Pharmacotherapy For Addiction Research Articles

Pharmacogenetic randomized trial for cocaine abuse: Disulfiram and α1A-adrenoceptor gene variation

Disulfiram is a cocaine addiction pharmacotherapy that inhibits dopamine β-hydroxylase (DβH) and reduces norepinephrine production. We examined whether a functional variant of the ADRA1A gene (Cys to Arg at codon 347 in exon 2, Cys347Arg) may enhance treatment response through decreased stimulation of this α1A-adrenoceptor, since antagonists of this receptor show promise in reducing cocaine use. Sixty-nine cocaine and opioid co-dependent (DSM-IV) subjects were stabilized on methadone for two weeks and subsequently randomized into disulfiram (250mg/day, N=32) and placebo groups (N=37) for 10 weeks. We genotyped the ADRA1A gene polymorphism (rs1048101) and evaluated its role for increasing cocaine free urines in those subjects treated with disulfiram using repeated measures analysis of variance, corrected for population structure. The 47 patients who carried at least one T allele of rs1048101 (TT or TC genotype) reduced their cocaine positive urines from 84% to 56% on disulfiram (p=0.0001), while the 22 patients with the major allele CC genotype showed no disulfiram effect. This study indicates that a patient's ADRA1A genotype could be used to identify a subset of individuals for which disulfiram and, perhaps, other α1-adrenoceptor blockers may be an effective pharmacotherapy for cocaine dependence.

ANKK1 and DRD2 pharmacogenetics of disulfiram treatment for cocaine abuse

Disulfiram is a potential cocaine addiction pharmacotherapy. Since dopamine deficiency has been found with cocaine addiction, our objective was to examine whether functional variants in the ankyrin repeat and kinase domain-containing 1 (ANKK1) and/or the dopamine receptor D2 (DRD2) genes interact with response to treatment with disulfiram. Cocaine and opioid codependent (DSM-IV) patients were stabilized on methadone and subsequently randomized into treatment groups - disulfiram (250 mg/day, N=31) or placebo (N=37). They were genotyped for ANKK1 (rs1800497) and DRD2 (rs2283265) polymorphisms, and the data were evaluated for an association between a cocaine-free state, as assessed by cocaine-free urine samples, and disulfiram treatment. Data were analyzed using repeated measures analysis of variance corrected for population structure. Patients with CT or TT ANKK1 genotypes dropped from 80 to 52% cocaine-positive urines on disulfiram (N=13; P≤0.0001), whereas those on placebo (N=20) showed no treatment effect. Patients carrying the CC ANKK1 genotype showed no effect on treatment with disulfiram (N=18) or placebo (N=17). The GT/TT DRD2 genotype group showed a significant decrease in the number of cocaine-positive urine samples on disulfiram (N=9; 67-48%; P ≤ 0.0001), whereas the GG DRD2 genotype group showed only a marginal decrease (N=23; 84-63%; P=0.04). Genotype pattern analysis revealed that individuals carrying at least one minor allele in either gene responded better to disulfiram treatment (N=13; P ≤ 0.0001) compared with individuals carrying only the major alleles (N=17). A patient's genotype for ANKK1, DRD2, or both, may be used to identify individuals for whom disulfiram may be an effective pharmacotherapy for cocaine dependence.

Detection of tobacco-related biomarkers in urine samples by surface-enhanced Raman spectroscopy coupled with thin-layer chromatography

The nicotine metabolites, cotinine and trans-3'-hydroxycotinine (3HC) are considered as superior biomarkers for identifying tobacco exposure. More importantly, the ratio of 3HC to cotinine is a good indicator to phenotype individuals for cytochrome P450 2A6 activity and to individualize pharmacotherapy for tobacco addiction. In this paper, a simple, robust and novel method based on surface-enhanced Raman spectroscopy coupled with thin-layer chromatography (TLC) was developed to directly quantify the biomarkers in human urine samples. This is the first time surface-enhanced Raman spectroscopy (SERS) was used to detect cotinine and 3HC in urine samples. The linear dynamic range for the detection of cotinine is from 40 nM to 8μM while that of 3HC is from 1μM to 15μM. The detection limits are 10nM and 0.2μM for cotinine and 3HC, respectively. The proposed method was further validated by quantifying the concentration of both cotinine and 3HC in smokers' urine samples. This TLC-SERS method allows the direct detection of cotinine in the urine samples of both active and passive smokers and the detection of 3HC in smokers.

Pharmacokinetics and central nervous system effects of the novel dual NK1/NK3 receptor antagonist GSK1144814 in alcohol‐intoxicated volunteers

Antagonism of both NK1 and NK3 receptors may be an effective strategy in the pharmacotherapy of schizophrenia, drug addiction or depression. GSK1144814 is a novel selective dual NK1 /NK3 receptor antagonist. The potential influence of GSK1144814 on the effects of alcohol was investigated. In a blinded, randomized, placebo-controlled, two period crossover study, the pharmacokinetics and central nervous system (CNS) effects of single oral doses of 200 mg GSK1144814 were evaluated in 20 healthy volunteers, using a controlled alcohol infusion paradigm to maintain stable alcohol concentrations with subsequent analysis of eye movements, adaptive tracking, body sway, visual analogue scales, Epworth sleepiness scale and the verbal visual learning test. Frequent adverse effects were mild somnolence, fatigue and headache. Plasma concentration of GSK1144814 in the presence of alcohol was maximal 1.5 h after dose administration. GSK1144814 did not affect alcohol pharmacokinetics. Co-administration of GSK1144814 and alcohol impaired saccadic reaction time and peak velocity, adaptive tracking, alertness, sleepiness, word recognition and recognition reaction time compared with administration of alcohol alone, but the size of the interaction was small. Administration of GSK1144814 in the presence of alcohol was generally well tolerated and not likely to produce clinically relevant additional impairments after alcohol consumption.

Effects of chronic treatment with the α2‐adrenergic agonist, lofexidine, on cocaine self‐administration

Cocaine's abuse related effects have been attributed to its interaction with dopamine systems. Although adrenergic receptors are located in brain areas that modulate dopaminergic activity, adrenergic agents have received little attention as potential pharmacotherapies for cocaine addiction. Lofexidine, a a2‐adrenergic agonist, is being investigated as a treatment for reducing opioid withdrawal symptoms but little is known about its direct interactions with drugs of abuse. The present study assessed the effects of chronic treatment with lofexidine on cocaine selfadministration. Male rhesus monkeys were trained under a second order FR2(VR16) schedule of food and cocaine reinforcement. Chronic treatment (7 days) with lofexidine (0.1–0.32 mg/kg/hr, IV) potentiated the reinforcing effects of cocaine as evidenced by a leftward shift in the cocaine dose‐effect curve. Chronic lofexidine had no effect on food‐maintained responding and mild side effects during treatment. Fewer overt behavioral effects were also seen upon cessation of treatment compared to clonidine (0.032–0.1 mg/kg/hr, IV). Although clinical studies also find that lofexidine produces few unwanted side effects and has minimal withdrawal effects compared to clonidine, its potentiation of cocaine's reinforcing effects makes it unlikely that lofexidine will be effective for cocaine abuse treatment. Supported by NIDA DA02519 and DA026892

2012 Update in addiction medicine for the generalist.

This article presents an update on addiction-related medical literature for the calendar years 2010 and 2011, focusing on studies that have implications for generalist practice. We present articles pertaining to medical comorbidities and complications, prescription drug misuse among patients with chronic pain, screening and brief interventions (SBIs), and pharmacotherapy for addiction.

Establishing the feasibility of measuring performance in use of addiction pharmacotherapy

This paper presents the rationale and feasibility of standardized performance measures for use of pharmacotherapy in the treatment of substance use disorders (SUD), an evidence-based practice and critical component of treatment that is often underused. These measures have been developed and specified by the Washington Circle, to measure treatment of alcohol and opioid dependence with FDA-approved prescription medications for use in office-based general health and addiction specialty care. Measures were pilot tested in private health plans, the Veterans Health Administration (VHA), and Medicaid. Testing revealed that use of standardized measures using administrative data for overall use and initiation of SUD pharmacotherapy is feasible and practical. Prevalence of diagnoses and use of pharmacotherapy vary widely across health systems. Pharmacotherapy is generally used in a limited portion of those for whom it might be indicated. An important methodological point is that results are sensitive to specifications, so that standardization is critical to measuring performance across systems.

Influence of the novel histamine H3 receptor antagonist ST1283 on voluntary alcohol consumption and ethanol-induced place preference in mice

Growing evidence supports a role for the central histaminergic system to have a modulatory influence on drug addiction in general and alcohol-use disorders in particular through histamine H3 receptors (H3R). In the present study, the effects of systemic injection of the newly synthesized H3R antagonist ST1283 on ethanol (EtOH) voluntary intake and EtOH-conditioned reward in mice have been investigated. Oral EtOH, saccharin, and quinine intake was assessed in a two-bottle choice paradigm using escalating concentrations of alcohol or tastant solutions. EtOH-induced place preference (CPP), EtOH-induced locomotor activity, and blood ethanol concentration (BEC) were also measured. Following administration of the H3R antagonist (2.5, 5, and 10 mg/kg, i.p.), there was a significant dose-dependent decrease in alcohol consumption and preference. Importantly, vehicle- and ST1283 (5 mg/kg)-treated mice showed similar consumption and preference to increasing concentration of both sweet and bitter tastes. More interestingly, systemic administration of ST1283 inhibited EtOH-CPP and EtOH-enhanced locomotion. This inhibition was blocked when mice were pretreated with the selective H3R agonist R-(alpha)-methyl-histamine (10 mg/kg). Finally, vehicle- and ST1283-treated mice had similar BECs. Our results show that ST1283 may decrease voluntary EtOH consumption and EtOH-CPP by altering its reinforcing effects, suggesting a novel role for histamine signaling in regulation of alcoholism. Lastly, the results add to the growing literature on H3R modulation in the pharmacotherapy of EtOH addiction.

Partial MHC/neuroantigen peptide constructs: a potential neuroimmune-based treatment for methamphetamine addiction.

Relapse rates following current methamphetamine abuse treatments are very high (∼40–60%), and the neuropsychiatric impairments (e.g., cognitive deficits, mood disorders) that arise and persist during remission from methamphetamine addiction likely contribute to these high relapse rates. Pharmacotherapeutic development of medications to treat addiction has focused on neurotransmitter systems with only limited success, and there are no Food and Drug Administration approved pharmacotherapies for methamphetamine addiction. A growing literature shows that methamphetamine alters peripheral and central immune functions and that immune factors such as cytokines, chemokines, and adhesion molecules play a role in the development and persistence of methamphetamine induced neuronal injury and neuropsychiatric impairments. The objective of this study was to evaluate the efficacy of a new immunotherapy, partial MHC/neuroantigen peptide construct (RTL551; pI-Ab/mMOG-35-55), in treating learning and memory impairments induced by repeated methamphetamine exposure. C57BL/6J mice were exposed to two different methamphetamine treatment regimens (using repeated doses of 4 mg/kg or 10 mg/kg, s.c.). Cognitive performance was assessed using the Morris water maze and CNS cytokine levels were measured by multiplex assay. Immunotherapy with RTL551 improved the memory impairments induced by repeated methamphetamine exposure in both mouse models of chronic methamphetamine addiction. Treatment with RTL551 also attenuated the methamphetamine induced increases in hypothalamic interleukin-2 (IL-2) levels. Collectively, these initial results indicate that neuroimmune targeted therapies, and specifically RTL551, may have potential as treatments for methamphetamine-induced neuropsychiatric impairments.

The Selective Dopamine β-Hydroxylase Inhibitor Nepicastat Attenuates Multiple Aspects of Cocaine-Seeking Behavior

Although norepinephrine (NE) does not typically modulate cocaine self-administration under traditional schedules of reinforcement, it is required for different inducers of the reinstatement of cocaine-seeking behavior via activation of multiple adrenergic receptor subtypes. We predicted that blockade of NE synthesis would attenuate all known modalities of reinstatement and showed previously that the selective dopamine β-hydroxylase inhibitor, nepicastat, had no effect on either maintenance of operant cocaine self-administration maintained on a fixed-ratio 1 schedule or reinstatement of food seeking but did abolish cocaine-primed reinstatement. In the present series of studies, we first evaluated the dose-dependent effect of nepicastat (5, 50, or 100 mg/kg) on novelty-induced locomotor activity and found that it blunted exploration only at the highest dose. Next, we assessed the ability of nepicastat (50 mg/kg) to reduce breakpoint responding for cocaine on a progressive ratio schedule and reinstatement induced by drug-associated cues and stress. We found that nepicastat significantly lowered the breakpoint for cocaine, but not for regular chow or sucrose, and attenuated cue-, footshock-, and yohimbine-induced reinstatement. Combined, these results indicate that nepicastat can reduce the reinforcing properties of cocaine under a stringent schedule and can attenuate relapse-like behavior produced by cocaine, formerly cocaine-paired cues, and physiological and pharmacological stressors. Thus, nepicastat is one of those rare compounds that can reduce reinforced cocaine seeking as well as all three reinstatement modalities, while sparing exploratory behavior and natural reward seeking, making it a promising pharmacotherapy for cocaine addiction.

The MTHFR C677T Variant is Associated with Responsiveness to Disulfiram Treatment for Cocaine Dependency.

Objective: Disulfiram is a one of the few pharmacotherapies for cocaine addiction that shows promise. Since disulfiram and cocaine both affect levels of global methylation we hypothesized the MTHFR gene, whose product is involved in supplying methyl groups for DNA and protein methylation, may be associated with responsiveness to disulfiram in cocaine-dependent individuals. Methods: Sixty-seven cocaine-dependent patients were stabilized on methadone for 2 weeks and then randomized into disulfiram (250 mg/day, N = 32) and placebo groups (N = 35) for 10 weeks. Patients were genotyped for the MTHFR (rs1801133, also known as C677T) polymorphism and the data was evaluated for association with cocaine-free urines in the disulfiram or placebo groups. Data from patients that completed all 10 weeks of the study (N = 56) were analyzed using repeated measures analysis of variance (ANOVA), corrected for population structure. Results: The CT or TT MTHFR genotype group (N = 32) dropped from 73 to 52% cocaine-positive urines on disulfiram (p = 0.0001), while the placebo group showed no treatment effect. The CC MTHFR genotype group (N = 24) showed a smaller, but still significant, reduction in cocaine-positive urines on disulfiram compared to placebo; 81–69% (p = 0.007). Conclusion: This study indicates that a patient’s MTHFR genotype may be used to identify individuals who might show improved response to disulfiram treatment for cocaine dependence. Clinical Trial: Pharmacogenetics of Disulfiram for Cocaine, clinicaltrials.gov/ct2/show/NCT00149630, NIDA-18197-2, NCT00149630.

VARENICLINE IN PATIENTS WITH CARDIOVASCULAR DISEASES – FRIEND OR ENEMY?

The problem of varenicline use in patients with cardiovascular diseases is discussed. Results of large clinical trials and meta-analyses with varenicline have proven its high efficacy for treatment of nicotine addiction in adults and a small number of side events. Varenicline is the main agent for pharmacotherapy of nicotine addiction due to its high efficacy and advantages of smoking cessation. However careful monitoring of its side effects is needed in these patients.

Psychostimulant-induced neuroadaptations in nucleus accumbens AMPA receptor transmission.

Medium spiny neurons of the nucleus accumbens serve as the interface between corticolimbic regions that elicit and modulate motivated behaviors, including those related to drugs of abuse, and motor regions responsible for their execution. Medium spiny neurons are excited primarily by AMPA-type glutamate receptors, making AMPA receptor transmission in the accumbens a key regulatory point for addictive behaviors. In animal models of cocaine addiction, changes in the strength of AMPA receptor transmission onto accumbens medium spiny neurons have been shown to underlie cocaine-induced behavioral adaptations related to cocaine seeking. Here we review changes in AMPA receptor levels and subunit composition that occur after discontinuing different types of cocaine exposure, as well as changes elicited by cocaine reexposure following abstinence or extinction. Signaling pathways that regulate these cocaine-induced adaptations will also be considered, as they represent potential targets for addiction pharmacotherapies.

Addiction pharmacotherapy: What do we know about access?

Advances in pharmacotherapy for addiction continue, with an increasing number of medications available to treat addictions. However, existence of medications does not necessarily translate to access for people with addictions. The presentations in this symposium address access to addiction pharmacotherapy, as evidenced by management techniques used by private health plans, medication usage in the specialty treatment system, the role of buprenorphine in expanding opioid agonist treatment, and the development of a performance measure to track addiction pharmacotherapy usage.

Access to addiction pharmacotherapy in private health plans

To understand access to addiction medications, it is essential to consider the role of private health plans and pharmacy benefit managers, which may use cost-sharing and administrative controls. We use 2010 data from a nationally representative survey of private health plans (n=351 health plans, 935 products; 89% response rate) to examine plans' management of addiction medications and how they encourage use of addiction pharmacotherapy. Addiction medications were rarely excluded from the formulary.

Drug court perspectives: Adopting operational and evidence based practices

Veterans Health Administration, and Medicaid. Testing revealed that use of standardized measures using administrative data for overall use and initiation of addiction pharmacotherapy is feasible and practical; that prevalence of diagnoses and use of pharmacotherapy vary widely across health systems; that pharmacotherapy is generally used in a limited portion of those for whom it might be indicated; and that results are sensitive to specifications, so that standardization is critical to measuring performance across systems.

Building consensus within the drug court

Measures were pilot tested in private health plans, the Veterans Health Administration, and Medicaid. Testing revealed that use of standardized measures using administrative data for overall use and initiation of addiction pharmacotherapy is feasible and practical; that prevalence of diagnoses and use of pharmacotherapy vary widely across health systems; that pharmacotherapy is generally used in a limited portion of those for whom it might be indicated; and that results are sensitive to specifications, so that standardization is critical to measuring performance across systems.

Assessing use of addiction pharmacotherapy: Results of a performance measure pilot test

Assessing use of addiction pharmacotherapy: Results of a performance measure pilot test

Pharmacogenetic Randomized Trial for Cocaine Abuse: Disulfiram and Dopamine β-Hydroxylase

Disulfiram has been an effective cocaine addiction pharmacotherapy, and one of its possible mechanisms of efficacy is through copper chelation and inhibition of an enzyme involved in catecholamine metabolism, dopamine β-hydroxylase (DβH), which converts dopamine to norepinephrine. A variant in the gene encoding DβH leads to reduced DβH activity, and as such, disulfiram might not be an effective treatment of cocaine dependence for individuals with this variant. This study explored that potential matching. Seventy-four cocaine- and opioid-codependent (DSM-V) subjects were stabilized on methadone for 2 weeks and subsequently randomized into disulfiram (250 mg/day, n = 34) and placebo groups (n = 40) for 10 weeks. We genotyped the DBH gene polymorphism, -1021C/T (rs1611115), that reduces DβH enzyme levels and evaluated its role for increasing cocaine free urines with disulfiram. With repeated measures analysis of variance, corrected for population structure, disulfiram pharmacotherapy reduced cocaine-positive urines from 80% to 62% (p = .0001), and this disulfiram efficacy differed by DBH genotype group. Patients with the normal DβH level genotype dropped from 84% to 56% on disulfiram (p = .0001), whereas those with the low DBH level genotype showed no disulfiram effect. This study indicates that the DBH genotype of a patient could be used to identify a subset of individuals for which disulfiram treatment might be an effective pharmacotherapy for cocaine dependence.

Modification of cocaine self-administration by buspirone (buspar®): potential involvement of D3 and D4 dopamine receptors.

Converging lines of evidence indicate that elevations in synaptic dopamine levels play a pivotal role in the reinforcing effects of cocaine, which are associated with its abuse liability. This evidence has led to the exploration of dopamine receptor blockers as pharmacotherapy for cocaine addiction. While neither D1 nor D2 receptor antagonists have proven effective, medications acting at two other potential targets, D3 and D4 receptors, have yet to be explored for this indication in the clinic. Buspirone, a 5-HT1A partial agonist approved for the treatment of anxiety, has been reported to also bind with high affinity to D3 and D4 receptors. In view of this biochemical profile, the present research was conducted to examine both the functional effects of buspirone on these receptors and, in non-human primates, its ability to modify the reinforcing effects of i.v. cocaine in a behaviourally selective manner. Radioligand binding studies confirmed that buspirone binds with high affinity to recombinant human D3 and D4 receptors (∼98 and ∼29 nm respectively). Live cell functional assays also revealed that buspirone, and its metabolites, function as antagonists at both D3 and D4 receptors. In behavioural studies, doses of buspirone that had inconsistent effects on food-maintained responding (0.1 or 0.3 mg/kg i.m.) produced a marked downward shift in the dose-effect function for cocaine-maintained behaviour, reflecting substantial decreases in self-administration of one or more unit doses of i.v. cocaine in each subject. These results support the further evaluation of buspirone as a candidate medication for the management of cocaine addiction.