Motor cortex and corticospinal excitability in humans with a history of illicit stimulant use

Illicit use of stimulant drugs such as methamphetamine, ecstasy, and cocaine is a current and growing problem throughout the world. The aim of the current study was to investigate the long-term effect of illicit stimulant use on human motor cortical and corticospinal circuitry. We hypothesized that individuals with a history of primarily methamphetamine and ecstasy use would exhibit altered corticospinal excitability and intracortical inhibition within motor cortex. The study involved 52 healthy adults (aged 26 ± 7 yr) comprising 26 abstinent stimulant users, 9 cannabis users, and 17 nondrug users. The experiment involved a routine urine drug screen, drug history questionnaire, neuropsychological assessment, and single- and paired-pulse transcranial magnetic stimulation (TMS) over motor cortex. EMG responses to stimulation [motor evoked potentials (MEPs)] were recorded from the contralateral first dorsal interosseus. At a given stimulus intensity, MEP area was significantly larger in abstinent stimulant users than in nondrug users during both relaxation (P = 0.045) and muscle contraction (P < 0.001). MEP latency was also significantly longer in abstinent stimulant users (P < 0.009), and they exhibited significantly greater muscle activity during performance of a given task (P = 0.004). However, resting motor threshold and the response to paired-pulse TMS were unaffected. The results suggest that abstinent stimulant users exhibit long-term changes in the excitability of motor cortical and corticospinal circuitry and muscle activity during movement. These changes may partly underlie anecdotal and objective reports of movement dysfunction in chronic stimulant users.

Methadone inhibits CYP2D6 and UGT2B7/2B4 in vivo: a study using codeine in methadone- and buprenorphine-maintained subjects

AIMS

To compare the O-demethylation (CYP2D6-mediated), N-demethylation (CYP3A4-mediated) and 6-glucuronidation (UGT2B4/7-mediated) metabolism of codeine between methadone- and buprenorphine-maintained CYP2D6 extensive metabolizer subjects.

METHODS

Ten methadone- and eight buprenorphine-maintained subjects received a single 60 mg dose of codeine phosphate. Blood was collected at 3 h and urine over 6 h and assayed for codeine, norcodeine, morphine, morphine-3- and -6-glucuronides and codeine-6-glucuronide.

RESULTS

The urinary metabolic ratio for O-demethylation was significantly higher (P= 0.0044) in the subjects taking methadone (mean ± SD, 2.8 ± 3.1) compared with those taking buprenorphine (0.60 ± 0.43), likewise for 6-glucuronide formation (0.31 ± 0.24 vs. 0.053 ± 0.027; P < 0.0002), but there was no significant difference (P= 0.36) in N-demethylation. Similar changes in plasma metabolic ratios were also found. In plasma, compared with those maintained on buprenorphine, the methadone-maintained subjects had increased codeine and norcodeine concentrations (P < 0.004), similar morphine (P= 0.72) and lower morphine-3- and -6- and codeine-6-glucuronide concentrations (P < 0.008).

CONCLUSION

Methadone is associated with inhibition of CYP2D6 and UGTs 2B4 and 2B7 reactions in vivo, even though it is not a substrate for these enzymes. Plasma morphine was not altered, owing to the opposing effects of inhibition of both formation and elimination; however, morphine-6-glucuronide (analgesically active) concentrations were substantially reduced. Drug interactions with methadone are likely to include drugs metabolized by various UGTs and CYP2D6.

ABCB1 haplotype and OPRM1 118A > G genotype interaction in methadone maintenance treatment pharmacogenetics

BACKGROUND

Genetic variability in ABCB1, encoding the P-glycoprotein efflux transporter, has been linked to altered methadone maintenance treatment dose requirements. However, subsequent studies have indicated that additional environmental or genetic factors may confound ABCB1 pharmacogenetics in different methadone maintenance treatment settings. There is evidence that genetic variability in OPRM1, encoding the mu opioid receptor, and ABCB1 may interact to affect morphine response in opposite ways. This study aimed to examine whether a similar gene-gene interaction occurs for methadone in methadone maintenance treatment.

METHODS

Opioid-dependent subjects (n = 119) maintained on methadone (15-300 mg/day) were genotyped for five single nucleotide polymorphisms of ABCB1 (61A > G; 1199G > A; 1236C > T; 2677G > T; 3435C > T), as well as for the OPRM1 118A > G single nucleotide polymorphism. Subjects' methadone doses and trough plasma (R)-methadone concentrations (C(trough)) were compared between ABCB1 haplotypes (with and without controlling for OPRM1 genotype), and between OPRM1 genotypes (with and without controlling for ABCB1 haplotype).

RESULTS

Among wild-type OPRM1 subjects, an ABCB1 variant haplotype group (subjects with a wild-type and 61A:1199G:1236C:2677T:3435T haplotype combination, or homozygous for the 61A:1199G:1236C:2677T:3435T haplotype) had significantly lower doses (median ± standard deviation 35 ± 5 versus 180 ± 65 mg/day, P < 0.01) and C(trough) (78 ± 22 versus 177 ± 97 ng/mL, P < 0.05) than ABCB1 wild-type subjects. Among subjects with the most common ABCB1 haplotype combination (wild-type with 61A:1199G:1236T:2677T:3435T), the OPRM1 118 A/G genotype was associated with a significantly higher C(trough) than 118 A/A (250 ± 126 versus 108 ± 36 ng/mL, P = 0.016). No ABCB1 haplotype group or OPRM1 genotype was associated with dose or C(trough) without taking into account confounding genetic variability at the other locus. Therefore, two interacting pharmacogenetic determinants of methadone maintenance treatment response were identified, ie, ABCB1, where variants are associated with lower methadone requirements, and OPRM1, where the variant is associated with higher methadone requirements.

CONCLUSION

These opposing pharmacogenetic effects therefore need to be considered in combination when assessing methadone maintenance treatment pharmacogenetics.

A randomized clinical trial of anticaries therapies targeted according to risk assessment (caries management by risk assessment)

This randomized parallel group clinical trial assessed whether combined antibacterial and fluoride therapy benefits the balance between caries pathological and protective factors. Eligible, enrolled adults (n = 231), with 1-7 baseline cavitated teeth, attending a dental school clinic were randomly assigned to a control or intervention group. Salivary mutans streptococci (MS), lactobacilli (LB), fluoride (F) level, and resulting caries risk status (low or high) assays were determined at baseline and every 6 months. After baseline, all cavitated teeth were restored. An examiner masked to group conducted caries exams at baseline and 2 years after completing restorations. The intervention group used fluoride dentifrice (1,100 ppm F as NaF), 0.12% chlorhexidine gluconate rinse based upon bacterial challenge (MS and LB), and 0.05% NaF rinse based upon salivary F. For the primary outcome, mean caries increment, no statistically significant difference was observed (24% difference between control and intervention groups, p = 0.101). However, the supplemental adjusted zero-inflated Poisson caries increment (change in DMFS) model showed the intervention group had a statistically significantly 24% lower mean than the control group (p = 0.020). Overall, caries risk reduced significantly in intervention versus control over 2 years (baseline adjusted generalized linear mixed models odds ratio, aOR = 3.45; 95% CI: 1.67, 7.13). Change in MS bacterial challenge differed significantly between groups (aOR = 6.70; 95% CI: 2.96, 15.13) but not for LB or F. Targeted antibacterial and fluoride therapy based on salivary microbial and fluoride levels favorably altered the balance between pathological and protective caries risk factors.

The effect of methadone on emotional reactivity

AIMS

Opioids have been implicated in emotion regulation. Opioid users report decreased negative emotional response, but there has been no formal study on the effect of opioid administration on emotional reactivity. The aim of this study was to investigate the effect of methadone on emotional reactivity in methadone-maintained patients.

DESIGN

Velten's mood induction procedures were used to induce elative and depressive emotional reactions in the subjects. Each group was administered both induction procedures at 0 hour and 3 hours (corresponding with trough and peak plasma methadone concentrations in methadone subjects).

SETTING

A drug treatment clinic with an out-patient methadone maintenance treatment programme.

PARTICIPANTS

Twenty-one subjects currently on methadone maintenance treatment and 21 controls with no history of opioid dependence.

MEASUREMENTS

Emotional reactivity was measured using mood visual analogue scales.

FINDINGS

At 0 hour, methadone and control subjects showed similar elation (methadone 13.2 ± 3.1 mean ± standard error of the mean [SEM], control 14.4 ± 3.7) and depression reactivity (methadone 23.6 ± 5.0, control 25.1 ± 5.0). However, at 3 hours repeated measures showed that methadone subjects had significantly decreased depression reactivity (methadone 18.5 ± 4.6, control 36.7 ± 5.7; P = 0.021) and elation reactivity (methadone 4.4 ± 1.9, control 19.0 ± 2.4) compared to controls.

CONCLUSIONS

Opioid addicts on methadone maintenance appear to be less reactive to mood induction at times of peak plasma methadone concentration than non-addict controls; this suggests that methadone blunts both elative and depressive emotional reactivity.

Screening for Corynebacterium diphtheriae and Corynebacterium ulcerans in patients with upper respiratory tract infections 2007-2008: a multicentre European study

Diphtheria is now rare in most European countries but, when cases do arise, the case fatality rate is high (5-10%). Because few countries continue to routinely screen for the causative organisms of diphtheria, the extent to which they are circulating amongst different European populations is largely unknown. During 2007-2008, ten European countries each screened between 968 and 8551 throat swabs from patients with upper respiratory tract infections. Six toxigenic strains of Corynebacterium diphtheriae were identified: two from symptomatic patients in Latvia (the country with the highest reported incidence of diphtheria in the European Union) and four from Lithuania (two cases, two carriers); the last reported case of diphtheria in Lithuania was in 2002. Carriage rates of non-toxigenic organisms ranged from 0 (Bulgaria, Finland, Greece, Ireland, Italy) to 4.0 per 1000 (95% CI 2.0-7.1) in Turkey. A total of 28 non-toxigenic strains were identified during the study (26 C. diphtheriae, one Corynebacterium ulcerans, one Corynebacterium pseudotuberculosis). The non-toxigenic C. ulcerans strain was isolated from the UK, the country with the highest reported incidence of cases due to C. ulcerans. Of the eleven ribotypes detected, Cluj was seen most frequently in the non-toxigenic isolates and, amongst toxigenic isolates, the major epidemic clone, Sankt-Petersburg, is still in circulation. Isolation of toxigenic C. diphtheriae and non-toxigenic C. diphtheriae and C. ulcerans in highly-vaccinated populations highlights the need to maintain microbiological surveillance, laboratory expertise and an awareness of these organisms amongst public health specialists, microbiologists and clinicians.

Pill content, dose and resulting plasma concentrations of 3,4-methylendioxymethamphetamine (MDMA) in recreational 'ecstasy' users

AIMS

To improve our understanding of the pharmacology of 'ecstasy' in recreational environments; in particular, to describe the composition of ecstasy pills, patterns of ecstasy use and the relationship between dose of 3,4-methylendioxymethamphetamine (MDMA) and resulting plasma concentrations.

DESIGN, SETTING AND PARTICIPANTS

A naturalistic observational study of 56 experienced 'ecstasy' users in recreational settings in Australia.

MEASUREMENTS

Drug use patterns (number of pills consumed, other drugs consumed). drug content of pills and resultant plasma concentrations of MDMA and related drugs were assessed by gas chromatography/mass spectrometry (GC/MS).

FINDINGS

Ecstasy pills generally contained MDMA, but this was often combined with other drugs such as 3,4-ethylendioxyethylamphetamine (MDEA) and methamphetamine. The dose of MDMA per pill ranged from 0 to 245 mg and users consumed from one-half to five pills, with the total dose consumed ranging up to 280 mg. Plasma concentrations of MDMA increased with number of pills consumed and cumulative MDMA dose. Use of larger numbers of pills was associated with extended exposure to the drug.

CONCLUSIONS

MDMA is the major active drug in ecstasy pills, but there is a high degree of variation in doses. Use of multiple pills over the course of one session is common and results in a sustained increase in MDMA plasma concentrations over a number of hours. This is likely to lead to a much greater exposure of the brain to MDMA than would be predicted from controlled single-dose pharmacokinetic studies.

(R)- and (S)-methadone and buprenorphine concentration ratios in maternal and umbilical cord plasma following chronic maintenance dosing in pregnancy

AIMS

The aim of this study was to compare the transfer of buprenorphine and methadone between maternal and cord blood in women under chronic dosing conditions and to determine if differences exist in the transfer of the two methadone enantiomers.

METHODS

Maternal and cord blood samples were collected at delivery from women maintained on methadone (35, 25-140 mg day⁻¹) (median; range) or buprenorphine (6.00, 2-20 mg day⁻¹) during pregnancy. Plasma concentration ratios are presented as an indicator of foetal exposure relative to the mother.

RESULTS

Methadone was quantified in all samples, with cord : maternal plasma methadone concentration ratios (n= 15 mother-infant pairs) being significantly higher (P < 0.0001; mean difference (MD) 0.07; 95% confidence interval (CI) 0.048, 0.092) for the active (R)-methadone enantiomer (0.41; 0.19, 0.56) (median; range) compared with (S)-methadone (0.36; 0.15, 0.53). (R)- : (S)-methadone concentration ratios were also significantly higher (P < 0.0001; MD 0.24 95% CI 0.300, 0.180) for cord (1.40; 0.95, 1.67) compared with maternal plasma (1.16; 0.81, 1.38). Half the infant buprenorphine samples were below the assay lower limit of quantification (LLOQ) (0.125 ng ml⁻¹). The latter was four-fold lower than the LLOQ for methadone (0.50 ng ml⁻¹). The cord : maternal plasma buprenorphine concentration ratio (n= 9 mother-infant pairs) was 0.35; 0.14, 0.47 and for norbuprenorphine 0.49; 0.24, 0.91.

CONCLUSIONS

The transfer of the individual methadone enantiomers to the foetal circulation is stereoselective. Infants born to buprenorphine maintained women are not exposed to a greater proportion of the maternal dose compared with methadone and may be exposed to relatively less of the maternal dose compared with infants born to women maintained on methadone during pregnancy.

Psychosocial treatment for methamphetamine use disorders: a preliminary randomized controlled trial of cognitive behavior therapy and Acceptance and Commitment Therapy

Acceptance and Commitment Therapy (ACT) incorporates developments in behavior therapy, holds promise but has not been evaluated for methamphetamine use disorders. The objective of this study was to test whether ACT would increase treatment attendance and reduce methamphetamine use and related harms compared to cognitive behavior therapy (CBT). One hundred and four treatment-seeking adults with methamphetamine abuse or dependence were randomly assigned to receive 12 weekly 60-minute individual sessions of ACT or CBT. Attrition was 70% at 12 weeks and 86% at 24 weeks postentry. Per intention-to-treat analysis, there were no significant differences between the treatment groups in treatment attendance (median 3 sessions), and methamphetamine-related outcomes; however, methamphetamine use (toxicology-assessed and self-reported), negative consequences, and dependence severity significantly improved over time in both groups. Although ACT did not improve treatment outcomes or attendance compared to CBT, it may be a viable alternative to CBT for methamphetamine use disorders. Future rigorous research in this area seems warranted.

The Psychostimulant Check-Up: A pilot study of a brief intervention to reduce illicit stimulant use

INTRODUCTION AND AIMS

This study is to test the acceptability of a single-session 'check-up' intervention for psychostimulant users and document participants' subsequent progress in reducing psychostimulant use and related harms.

DESIGN AND METHODS

The design was pre-experimental single-group repeated measures. Eighty participants received the Psychostimulant Check-Up, with 62% completing a 3 month follow up.

RESULTS

Participants were predominantly young adult methamphetamine users. The majority indicated that the Check-Up answered their questions, increased their awareness of services, and they would recommend it to their friends. At follow up, there was a significant reduction in self-reported methamphetamine use, the number of self-reported psychostimulant-related negative consequences experienced in the previous month and rates of injecting: 62% self-reported at least a 1 g reduction in methamphetamine use.

DISCUSSION AND CONCLUSIONS

The intervention was well accepted and the majority of those who received it subsequently made meaningful reductions in psychostimulant use and related harm. The intervention offers sufficient promise to warrant a randomised trial to establish whether improvements were specific to the intervention.

Changeover ratio effects on concurrent variable-interval performance

Rats' bar-pressing was maintained by concurrent variable-interval schedules of reinforcement. A fixed-ratio of pulls on a chain (the changeover ratio) was required for switching between schedules. The first experiment employed equal variable-interval schedules and symmetrical changeover ratios. Increasing these ratios resulted in a decrease in the rate of switching between schedules and an increase in local response rate. In the second experiment, a range of asymmetrical changeover ratios was used with equal variable-interval schedules, and a preference was found for the schedule associated with the larger switching-into ratio. Both the distributions of responses and time between the two schedules deviated from those expected on the basis of obtained reinforcers. In the third experiment, the switching-out-of ratio was dependent on the amount of time spent in a variable-interval 2-minute schedule; a constant ratio permitted switching out of the alternative variable-interval 1-minute schedule. A strong preference was shown for the variable-interval 2-minute schedule. The fourth experiment used equal variable-interval schedules; one changeover ratio was varied while the second remained constant. The results failed to show systematic differences in local response rates immediately after a changeover.

Inbreeding Effects upon Growth and Maternal Ability in Laboratory Mice

The effects of systematically increasing levels of inbreeding upon growth and postnatal maternal ability were determined in laboratory mice by utilizing the reciprocal crossfostering technique. Two experiments were conducted. The first included postnatal dams which were inbred 0, 12, 25 and 38% while corresponding levels in the litter were 0, 22, 38 and 50%, respectively. The second experiment included 0, 25, 50 and 73% inbred dams with litters inbred 0, 38, 59 and 79%, respectively. Increasing the level of inbreeding was found to linearly depress postnatal maternal performance. Young which had been suckled by the more inbred dams were smaller at 12 and 21 days of age than those which had been nursed by the more outbred dams. In the second experiment, these effects were carried over into the postweaning period. Increasing levels of inbreeding in the litter significantly depressed birth weight and weight at 12, 21, 42 and 56 days. The depressing effects of inbreeding in the litter were primarily linear for both males and females under the conditions of the more moderate levels of inbreeding included in the first experiment, but were curvilinear for females and linear for males in the second experiment. The curvilinearity in females was due to the general lack of depression until inbreeding had reached 50 to 60%, after which significant inbreeding depression developed.

Opioid antagonists under heavy sedation or anaesthesia for opioid withdrawal

BACKGROUND

Withdrawal (detoxification) is necessary prior to drug-free treatment or as the end point of long-term substitution treatment.

OBJECTIVES

To assess the effectiveness of opioid antagonists to induce opioid withdrawal with concomitant heavy sedation or anaesthesia, in terms of withdrawal signs and symptoms, completion of treatment and adverse effects.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3, 2009), Medline (January 1966 to 11 August 2009), Embase (January 1985 to 2009 Week 32), PsycINFO (1967 to July 2009), and reference lists of articles.

SELECTION CRITERIA

Controlled studies of antagonist-induced withdrawal under heavy sedation or anaesthesia in opioid-dependent participants compared with other approaches, or a different regime of anaesthesia-based antagonist-induced withdrawal.

DATA COLLECTION AND ANALYSIS

One reviewer assessed studies for inclusion, undertook data extraction and assessed quality. Inclusion decisions and the overall process were confirmed by consultation between all authors.

MAIN RESULTS

Nine studies (eight randomised controlled trials) involving 1109 participants met the inclusion criteria for the review.Antagonist-induced withdrawal is more intense but less prolonged than withdrawal managed with reducing doses of methadone, and doses of naltrexone sufficient for blockade of opioid effects can be established significantly more quickly with antagonist-induced withdrawal than withdrawal managed with clonidine and symptomatic medications. The level of sedation does not affect the intensity and duration of withdrawal, although the duration of anaesthesia may influence withdrawal severity. There is a significantly greater risk of adverse events with heavy, compared to light, sedation (RR 3.21, 95% CI 1.13 to 9.12, P = 0.03) and probably with this approach compared to other forms of detoxification.

AUTHORS' CONCLUSIONS

Heavy sedation compared to light sedation does not confer additional benefits in terms of less severe withdrawal or increased rates of commencement on naltrexone maintenance treatment. Given that the adverse events are potentially life-threatening, the value of antagonist-induced withdrawal under heavy sedation or anaesthesia is not supported. The high cost of anaesthesia-based approaches, both in monetary terms and use of scarce intensive care resources, suggest that this form of treatment should not be pursued.

Randomized controlled trial of dexamphetamine maintenance for the treatment of methamphetamine dependence

AIM

To investigate the safety and efficacy of once-daily supervised oral administration of sustained-release dexamphetamine in people dependent on methamphetamine.

DESIGN

Randomized, double-blind, placebo-controlled trial.

PARTICIPANTS

Forty-nine methamphetamine-dependent drug users from Drug and Alcohol Services South Australia (DASSA) clinics.

INTERVENTION

Participants were assigned randomly to receive up to 110 mg/day sustained-release dexamphetamine (n = 23) or placebo (n = 26) for a maximum of 12 weeks, with gradual reduction of the study medication over an additional 4 weeks. Medication was taken daily under pharmacist supervision.

MEASUREMENTS

Primary outcome measures included treatment retention, measures of methamphetamine consumption (self-report and hair analysis), degree of methamphetamine dependence and severity of methamphetamine withdrawal. Hair samples were analysed for methamphetamine using liquid chromatography-mass spectrometry.

FINDINGS

Treatment retention was significantly different between groups, with those who received dexamphetamine remaining in treatment for an average of 86.3 days compared with 48.6 days for those receiving placebo (P = 0.014). There were significant reductions in self-reported methamphetamine use between baseline and follow-up within each group (P < 0.0001), with a trend to a greater reduction among the dexamphetamine group (P = 0.086). Based on hair analysis, there was a significant decrease in methamphetamine concentration for both groups (P < 0.0001). At follow-up, degree of methamphetamine dependence was significantly lower in the dexamphetamine group (P = 0.042). Dexamphetamine maintenance was not associated with serious adverse events.

CONCLUSIONS

The results of this preliminary study have demonstrated that a maintenance pharmacotherapy programme of daily sustained-release amphetamine dispensing under pharmacist supervision is both feasible and safe. The increased retention in the dexamphetamine group, together with the general decreases in methamphetamine use, degree of dependence and withdrawal symptom severity, provide preliminary evidence that this may be an efficacious treatment option for methamphetamine dependence.

Model of methadone-induced hyperalgesia in rats and effect of memantine

Methadone used for opioid dependence therapy is associated with increased pain sensitivity. This study aimed to investigate whether methadone administration lowers nociceptive threshold in adult male Sprague-Dawley (SD) rats, and if this threshold could be altered by the NMDA receptor antagonist memantine. Rats were implanted with osmotic pumps delivering 1mg/kg/day methadone (n=6), or saline placebo (n=6) (0.51 microl/h). A separate cohort of rats received either methadone 1mg/kg/day (n=8) or methadone 1mg/kg/day with 20mg/kg/day memantine (n=8). Nociception was measured by the Hargreave's paw withdrawal test. Baseline nociception was measured on day 0 prior to osmotic pump implantation and was measured daily for the following 21 days. Osmotic pumps were removed following nociceptive testing on day 14. Methadone only treated rats had a mean paw withdrawal latency significantly lower than the corresponding values for saline on days 8, 9, 10, 11, 12, 14, and 17 (P<0.05). At all other time points the mean paw withdrawal latency was not significantly different from saline (P>0.05). Paw withdrawal latency of rats treated with methadone co-administered with memantine did not differ significantly compared to methadone only (P>0.05). This demonstrates that methadone induces hyperalgesia in the SD rat yet this hyperalgesia resolves following discontinuation of methadone administration. Furthermore, memantine does not alter the development of methadone-induced hyperalgesia.

A review of the international issues surrounding the availability and demand for diphtheria antitoxin for therapeutic use

Diphtheria treatment requires early administration of diphtheria antitoxin (DAT), an immunoglobulin preparation that neutralises circulating diphtheria toxin. Here, we review issues relating to the supply and use of DAT and assess its availability by means of an international survey. Results showed that several countries do not currently hold DAT stockpiles due to low prevalence, and hence perceived risk of diphtheria, and/or difficulties in obtaining DAT supplies. The potential for importation of cases into any country exists globally, since diphtheria remains endemic in many regions. It is therefore important that DAT be readily available - particularly since waning diphtheria immunity has been observed among adult populations in countries with good vaccination coverage. Options for diphtheria therapy are discussed.

Opioid antagonists with minimal sedation for opioid withdrawal

BACKGROUND

Managed withdrawal is a necessary step prior to drug-free treatment or as the end point of long-term substitution treatment.

OBJECTIVES

To assess the effectiveness of opioid antagonists in combination with minimal sedation to manage opioid withdrawal.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3, 2008), MEDLINE (January 1966-July 2008), EMBASE (January 1985-2008 Week 31), PsycINFO (1967 to 7 August 2008) and reference lists of articles.

SELECTION CRITERIA

Controlled studies of interventions involving the use of opioid antagonists in combination with minimal sedation to manage withdrawal in opioid-dependent participants compared with other approaches or different opioid antagonist regimes.

DATA COLLECTION AND ANALYSIS

One author assessed studies for inclusion and undertook data extraction. Inclusion decisions and the overall process were confirmed by consultation between all authors.

MAIN RESULTS

Nine studies (6 randomised controlled trials), involving 837 participants, met the inclusion criteria for the review.The quality of the evidence is low, but suggests that withdrawal induced by opioid antagonists in combination with an adrenergic agonist is more intense than withdrawal managed with clonidine or lofexidine alone, while the overall severity is less. Delirium may occur following the first dose of opioid antagonist, particularly with higher doses (> 25mg naltrexone).In some situations antagonist-induced withdrawal may be associated with significantly higher rates of completion of treatment, comp[ared to withdrawal managed primarily with adrenergic agonists. However, this outcome has not been produced consistently, and the extent of any benefit is highly uncertain.

AUTHORS' CONCLUSIONS

The use of opioid antagonists combined with alpha(2)-adrenergic agonists is a feasible approach to the management of opioid withdrawal. However, it is unclear whether this approach reduces the duration of withdrawal or facilitates transfer to naltrexone treatment to a greater extent than withdrawal managed primarily with an adrenergic agonist.A high level of monitoring and support is desirable for several hours following administration of opioid antagonists because of the possibility of vomiting, diarrhoea and delirium.Further research is required to confirm the relative effectiveness of antagonist-induced regimes, as well as variables influencing the severity of withdrawal, adverse effects, the most effective antagonist-based treatment regime, and approaches that might increase retention in subsequent naltrexone maintenance treatment.

Buprenorphine for the management of opioid withdrawal

BACKGROUND

Managed withdrawal is a necessary step prior to drug-free treatment or as the end point of substitution treatment.

OBJECTIVES

To assess the effectiveness of interventions involving the use of buprenorphine to manage opioid withdrawal, for withdrawal signs and symptoms, completion of withdrawal and adverse effects.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3, 2008), MEDLINE (January 1966 to July 2008), EMBASE (January 1985 to 2008 Week 31), PsycINFO (1967 to 7 August 2008) and reference lists of articles.

SELECTION CRITERIA

Randomised controlled trials of interventions involving the use of buprenorphine to modify the signs and symptoms of withdrawal in participants who were primarily opioid dependent. Comparison interventions involved reducing doses of methadone, alpha(2)-adrenergic agonists, symptomatic medications or placebo, or different buprenorphine-based regimes.

DATA COLLECTION AND ANALYSIS

One author assessed studies for inclusion and methodological quality, and undertook data extraction. Inclusion decisions and the overall process was confirmed by consultation between all authors.

MAIN RESULTS

Twenty-two studies involving 1736 participants were included. The major comparisons were with methadone (5 studies) and clonidine or lofexidine (12 studies). Five studies compared different rates of buprenorphine dose reduction.Severity of withdrawal is similar for withdrawal managed with buprenorphine and withdrawal managed with methadone, but withdrawal symptoms may resolve more quickly with buprenorphine. It appears that completion of withdrawal treatment may be more likely with buprenorphine relative to methadone (RR 1.18; 95% CI 0.93 to 1.49, P = 0.18) but more studies are required to confirm this.Relative to clonidine or lofexidine, buprenorphine is more effective in ameliorating the symptoms of withdrawal, patients treated with buprenorphine stay in treatment for longer (SMD 0.92, 95% CI 0.57 to 1.27, P < 0.001), and are more likely to complete withdrawal treatment (RR 1.64; 95% CI 1.31 to 2.06, P < 0.001). At the same time there is no significant difference in the incidence of adverse effects, but drop-out due to adverse effects may be more likely with clonidine.

AUTHORS' CONCLUSIONS

Buprenorphine is more effective than clonidine or lofexidine for the management of opioid withdrawal. Buprenorphine may offer some advantages over methadone, at least in inpatient settings, in terms of quicker resolution of withdrawal symptoms and possibly slightly higher rates of completion of withdrawal.

The addition of oral idarubicin to a chlorambucil/dexamethasone combination has a significant impact on time to treatment failure but none on overall survival in patients with low grade non-Hodgkin's lymphoma: Results of the Scotland and Newcastle Lymphoma Group randomized NHL VIII trial

Two hundred untreated patients with low grade NHL (KIEL), including 155 follicular NHL, were randomized to six courses of treatment with chlorambucil 20 mg m-2 for 3 days and dexamethasone 4 mg bd for 5 days (CD) vs the same regimen plus oral idarubicin 10 mg m-2 for 3 days (CID). Responding patients could be randomized to no further treatment or maintenance treatment for up to 36 months with alpha interferon. Complete remissions/CRu were more frequent in the CID arm (35% vs 24%) but the overall response rate was similar; 87/91 (96%) vs 86/92 (93%). Overall survival (OS) did not differ between the two arms. Time to treatment failure (TTTF) was prolonged in the CID arm, p = 0.03; median time 28 vs 19 months. TTTF for the B-cell follicular group alone was for CID (77 patients) 33 months vs 18 months for CD (78 patients). Interferon conferred no apparent benefit. The Follicular Lymphoma International Prognostic Index (FLIPI) is confirmed as a good predictor of risk groups including a group of 23% with shorter survival. The addition of the oral anthracycline, idarubicin, led to a significant improvement in TTTF with low toxicity. The use of radiotherapy in this sub-group may have contributed to this result. CID is a potential for combination with antibody therapy particularly in older patient groups.

Pharmacological properties of ketamine

Ketamine is a dissociative anaesthetic that is being used in non-medical contexts. The effects of ketamine are very similar to those of phencyclidine, another dissociative anaesthetic that has enjoyed considerable popularity as a recreational drug. The effects of ketamine include analgesia, cardiovascular and respiratory stimulation, dissociation, hallucinations and anaesthesia. The potential dangers of uncontrolled ketamine use include psychosis and violence, accidents and marked psychomotor and cognitive impairment. Although studies have shown potential for tolerance to and physical dependence on ketamine, further investigation of these phenomena is needed. Ketamine is thought to produce most of its effects through antagonist activity at the PCP site of the NMDA receptor complex. Ketamine has sympathomimetic properties resulting from enhancement of catecholamine, and particularly dopamine, activity. While opioid receptor activity has been identified, this is relatively weak and the contribution to the effects of ketamine is not clear. Although much is known of the clinical uses and effects of ketamine, as yet little is understood of ketamine as a recreational drug and potential drug of dependence.

Improvements in retention rates and changes in client group with methadone maintenance streaming

This study evaluated changes in client population and in retention rates following the introduction of a system of methadone maintenance streaming. A low intervention and low supervision stream was combined with two abstinence-orientated streams. Privileges of take-home doses and local pharmacy dose collection were contingent on successful participation in the abstinence-orientated streams. The clinic also modified policy to allow clients greater control over dose levels. The case notes of the first 100 clients entering the programme in the year prior to the changes (1991) and in the year following the changes (1993) were compared. The results showed a significant increase in retention rates. The demographic and heroin using histories did not change, but the newer programme attracted a greater proportion of clients with no previous history of methadone maintenance treatment. Mean clinic dose increased from 45 mg to 63 mg when clients were allowed to exert control over dose. These findings reveal improved outcomes in a public methadone maintenance programme as a result of policy changes designed to give clients greater control of their treatment.