Alpha2-adrenergic agonists for the management of opioid withdrawal

BACKGROUND

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 interventions involving the use of alpha2-adrenergic agonists 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. We also contacted manufacturers in the field.

SELECTION CRITERIA

Controlled trials comparing alpha2-adrenergic agonists with reducing doses of methadone, symptomatic medications or placebo, or comparing different alpha2-adrenergic agonists to modify the signs and symptoms of withdrawal in participants who were opioid dependent.

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

Twenty-four studies, involving 1631 participants, were included. Twenty-one were randomised controlled trials.Thirteen studies compared a treatment regime based on an alpha2-adrenergic agonist with one based on reducing doses of methadone. Diversity in study design, assessment and reporting of outcomes limited the extent of quantitative analysis.Alpha2-adrenergic agonists are more effective than placebo in ameliorating withdrawal, and despite higher rates of adverse effects, are associated with significantly higher rates of completion of treatment.For the comparison of alpha2-adrenergic agonist regimes with reducing doses of methadone, there were insufficient data for statistical analysis, but withdrawal intensity appears similar to or marginally greater with alpha2-adrenergic agonists, while signs and symptoms of withdrawal occur and resolve earlier. Participants stay in treatment longer with methadone. No significant difference was detected in rates of completion of withdrawal with adrenergic agonists compared to reducing doses of methadone, or clonidine compared to lofexidine. Clonidine is associated with more adverse effects than reducing doses of methadone. Lofexidine does not reduce blood pressure to the same extent as clonidine, but is otherwise similar to clonidine

AUTHORS' CONCLUSIONS

Clonidine and lofexidine are more effective than placebo for the management of withdrawal from heroin or methadone. No significant difference in efficacy was detected for treatment regimes based on clonidine or lofexidine, and those based on reducing doses of methadone over a period of around 10 days but methadone is associated with fewer adverse effects than clonidine, and lofexidine has a better safety profile than clonidine.

Diagnostic accuracy of digital photography and image analysis for the measurement of foot conformation in the horse

REASONS FOR PERFORMING STUDY

Rigorous evaluation of practicable methods for the objective assessment of foot conformation has not been performed.

OBJECTIVES

To assess the practicability, precision and accuracy of the process of obtaining measurements of horses' feet using photography and image processing software.

METHODS

Precision study: Lateral photographs of horses' feet were obtained twice by 2 veterinary surgeons (image acquisition - IAc). Photographs were analysed by 2 masked veterinary surgeons on 2 occasions (image analysis - IAn). Measurements were compared within and between operators for self and non-self acquired photographs. Agreement indices (AIs) and 95% limits of agreement (LOA) were calculated for the IAn process alone and for the combined IAc + IAn processes. Accuracy study: Measurements obtained from lateral photographs were compared with those obtained from lateromedial radiographs. AIs and 95% LOA were calculated for each measurement.

RESULTS

Precision study: Mean intra- and interoperator AIs for the IAn process alone were > or = 0.90 while those for the combined IAc + IAn processes were > or = 0.89 for all measurements. Similar mean AIs and 95% LOA were calculated regardless of image origin. The 95% LOA for hoof angle, heel height/toe height% and coronary band angle for all comparisons were within target values. Accuracy study: Mean AIs were > or = 0.89 for all measurements. The 95% LOA for heel height/toe height% and coronary band angle were within target values.

CONCLUSIONS

Excellent precision was identified within and between operators regardless of image origin. High levels of accuracy were also identified, especially for heel height/toe height% and coronary band angle, indicating that photography and radiography may be used interchangeably.

POTENTIAL RELEVANCE

Acquisition and analysis of photographic images is an appropriate method for the objective measurement of foot conformation, both in clinical and, research settings.

Flexible dosing of tincture of opium in the management of opioid withdrawal: pharmacokinetics and pharmacodynamics

AIMS

The aim was to evaluate the clinical effectiveness, pharmacodynamics and pharmacokinetics of a range of Tincture of Opium (TOP) doses in the management of opioid withdrawal.

METHODS

Forty-five opium-dependent Thai subjects were allocated to three dosing groups (6.66, 13.3 and 20 mg morphine equivalents, twice daily) depending on their self-reported prior opium use. On day 5 of dosing subjects underwent an interdosing interval study where blood, withdrawal scores, heart rate and blood pressure (BP) were collected at 0, 1, 3 and 8 h. Plasma morphine concentrations were quantified by high-performance liquid chromatography, and plasma morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) concentrations by LCMS.

RESULTS

Thirty-two subjects completed the study. Withdrawal scores were low for all subjects (range 9-23% of maximum response). There were dose-dependent changes in both systolic and diastolic BP (P = 0.021 and P = 0.01, respectively), but these were not considered clinically significant. There were no effects of dose on respiratory rate. Plasma morphine concentrations changed significantly across the interdosing interval (P = 0.0001), rising to a maximum at 1 h after dosing. Plasma morphine concentrations also differed according to dose (P < 0.05). The mean ratios of the morphine glucuronides were found to be: M3G/M6G = 7.7, M3G/morphine = 35.6 and M6G/morphine = 4.9, values comparable to those previously reported.

CONCLUSION

The management of opioid withdrawal can be achieved, with minimal adverse effects, by using flexible dosing of TOP.

Preparation and characterization of Pd-Ti electrocatalyst on carbon supports for oxygen reduction

Nanoscale bimetallic Pd-Ti catalysts on carbon supports were prepared in liquid using ammonium tetrachloropalladate and titanium isopropoxide. The size of the metal particles ranged from subnanometer to greater than 10 nm, and the X-ray diffraction pattern of metal particles was dominated by a cubic crystalline structure. Depending upon the preparation conditions, the catalysts were comprised of Pd and TiO2 or Pd3Ti-like alloy. The surface Ti/Pd ratio was much greater than the original metal loading. We propose that the bimetallic particles were comprised of short-range Pd and TiO2 or Pd-Ti alloy nanocrystal covered by a thin TiO2 layer.

High throughput operando studies using Fourier transform infrared imaging and Raman spectroscopy

A prototype high throughput operando (HTO) reactor designed and built for catalyst screening and characterization combines Fourier transform infrared (FT-IR) imaging and Raman spectroscopy in operando conditions. Using a focal plane array detector (HgCdTe focal plane array, 128x128 pixels, and 1610 Hz frame rate) for the FT-IR imaging system, the catalyst activity and selectivity of all parallel reaction channels can be simultaneously followed. Each image data set possesses 16 384 IR spectra with a spectral range of 800-4000 cm(-1) and with an 8 cm(-1) resolution. Depending on the signal-to-noise ratio, 2-20 s are needed to generate a full image of all reaction channels for a data set. Results on reactant conversion and product selectivity are obtained from FT-IR spectral analysis. Six novel Raman probes, one for each reaction channel, were specially designed and house built at Pacific Northwest National Laboratory, to simultaneously collect Raman spectra of the catalysts and possible reaction intermediates on the catalyst surface under operando conditions. As a model system, methanol partial oxidation reaction on silica-supported molybdenum oxide (MoO3SiO2) catalysts has been studied under different reaction conditions to demonstrate the performance of the HTO reactor.

Draft protocol for testing calibration and quality control material used with automatic blood-counting apparatus

A large number of commercial preparations are now available for calibrating or checking the stability of automatic blood counters. Most of these preparations are supplied with 'stated' values though the methods for assigning these values are not described in sufficient detail to allow for an adequate assessment of the validity. The Haemocytometry Panel of the British Committee for Standards in Haematology are therefore proposing a draft protocol for testing calibration and quality control materials. Comments on the draft protocol are invited, either as letters to the Editor of Clinical and Laboratory Haematology or in confidence to the Chairman of the Haemocytometry Panel.

Inter- and intra-subject variability in ethanol pharmacokinetic parameters: Effects of testing interval and dose

Calculation of a blood alcohol concentration (BAC) at the time of an offence by forward or back-extrapolation, using population average values for ethanol pharmacokinetic parameters or a single estimate of individual specific parameters, ignores the possibility of inter- and intra-subject variability. In order to estimate inter- and intra-subject variability in the elimination rate and absorption rate, BAC was measured over time in 12 male volunteers on 4 occasions. Subjects received 0.44 g kg(-1) body weight of ethanol on the first study day, and 0.70 g kg(-1) body weight on subsequent study days 1, 11 and 12 weeks later, to enable comparisons in variability over short and long time periods and when the same or different doses were administered. Evidence of both inter- and intra-subject variability was found, with inter-subject variability substantially smaller than intra-subject variability when the dose varied. Forensically important differences in pharmacokinetic parameters were observed within individuals between occasions. These findings could have an important impact on medico-legal issues related to ethanol pharmacokinetics.

Imaging intrinsic diffusion of bridge-bonded oxygen vacancies on TiO2(110)

We report the first measurements and calculations of the intrinsic mobility of bridge-bonded oxygen (BBO) vacancies on a rutile TiO2(110). The sequences of isothermal (340-420 K) scanning tunneling microscope images show that BBO vacancies migrate along BBO rows. The hopping rate increases exponentially with increasing temperature with an experimental activation energy of 1.15 eV. Density functional theory calculations are in very good agreement giving an energy barrier for hopping of 1.03 eV. Both theory and experiment indicate repulsive interactions between vacancies on a given BBO row.

Psychometric evaluation of the Amphetamine Cessation Symptom Assessment

Testing of a new scale, the Amphetamine Cessation Symptom Assessment (ACSA), in a sample of treatment-seeking amphetamine users (N = 133) showed satisfactory reliability, while factor analysis identified three components explaining 64.7% of the variance in scores. Scores were inversely related to subjective general well-being (r = -.33, p < .01) and directly related to the Beck Depression Inventory (r = .59, p < .01). There were positive relationships between the ACSA and measures of amphetamine dependence (r = .36, p < .01) and the intensity of recent amphetamine use (r = .24, p < .01). The ACSA discriminated between "low-dose" and "high-dose" users, indicating discriminant validity. In inpatients (n = 63), ACSA scores declined significantly over time, while higher scores in inpatient treatment dropouts indicated predictive validity. The ACSA showed satisfactory reliability and validity, with a three-factor solution providing the best fit to the data. The ACSA could play an important role in providing clinical outcome data, particularly in outcome evaluation of new treatment protocols.

Trimethyl acetate on TiO2(110): preparation and anaerobic photolysis

The preparation and anaerobic ultraviolet photolysis of trimethyl acetate (TMA) on rutile TiO(2)(110) have been examined with an emphasis on reaction paths. Substrates for photolysis were prepared by dosing trimethyl acetic acid at 100, 300, and 550 K. The chemistry was characterized by mass spectrometry during dosing and by H(2)O adsorption and temperature programmed desorption (TPD) after dosing. Using TPD after photolysis and mass spectrometry during photolysis, the products ejected and retained during photolysis were sought. The photolysis results are interpreted using the following mechanistic model. Photons with energies exceeding 3 eV create electron-hole pairs in the substrate. With probabilities of 10(-5) or lower, the holes initiate TMA chemistry by extracting an electron from the pi orbital of the carboxylate moiety. The accompanying electrons are trapped at the surface and inhibit subsequent events of this chemistry. The electron-deficient intermediate, TMA, decarboxylates to form CO(2) and either chemisorbed tert-butyl (-C(CH(3))(3)) or physisorbed i-butene. For photolysis at 100 or 200 K, the -C(CH(3))(3) accumulates and there is a slow photon-driven secondary reaction that, with a source of H, hydrogenates adsorbed tert-butyl to physisorbed i-butane. For photolysis at 300 K, -C(CH(3))(3) thermally reacts to form and desorb i-butene and i-butane during photolysis.

Enhanced Buprenorphine Analgesia with the Addition of Ultra-low-dose Naloxone in Healthy Subjects

Animal studies have demonstrated that co-administration of an ultra-low-dose opioid antagonist with an opioid agonist may result in enhanced analgesia. Investigation of this effect in humans has been limited and produced inconsistent findings, with previous reports suggesting that dose ratio may be critical to analgesic potentiation. The aim of the current investigation was to determine whether buprenorphine analgesia could be enhanced with the addition of ultra-low-dose naloxone among healthy volunteers, using a range of dose ratios. Tolerance to cold pressor pain was significantly greater with the combination of buprenorphine and naloxone compared to buprenorphine alone, and this effect was dose ratio dependent. Importantly, this enhanced analgesia occurred without an increase in adverse effects; indeed at some ratios, respiratory depression was attenuated. These findings demonstrate that the addition of ultra-low-dose naloxone can enhance the analgesic effect of buprenorphine in humans without a concurrent increase in side effects.

Pinastric acid revisited: a complete NMR and X-ray structure assignment

Chemical investigation of a terrestrial lichen has yielded the pulvinic acid derivative pinastric acid (4). The structure of 4 was secured by detailed spectroscopic analysis as well as via a single X-ray diffraction study. This is the first report of the X-ray structure and 2D NMR assignment of pinastric acid (4). Pinastric acid (4) displayed antitumour, antiviral and antimicrobial (both antibacterial and antifungal) activities. Whilst the antiviral and antimicrobial activities are consistent with previous findings of 4 this is the first report of the antitumour properties for the compound.

Switching between methadone and morphine for maintenance treatment of opioid dependence: impact on pain sensitivity and mood status

Methadone maintenance is associated with hyperalgesia and elevated mood disturbance-effects opposite to those induced by acute opioid administration, which may undermine outcomes during substitution therapy. This study examined the impact of switching between methadone and slow-release morphine on pain sensitivity and mood status in 14 methadone maintenance patients using an open-label crossover design. Pain responses were nearly identical for each drug. Patients reporting inadequate withdrawal suppression on methadone showed greater mood stability when transferred to morphine, but overall mood disturbance levels did not differ between drugs. Hyperalgesia and mood disturbance cannot be resolved by changing from methadone to morphine maintenance.

Opioid maintenance: a comparative review of pharmacological strategies

The use of opioids outside of medical practice is a significant health problem with important social and political implications. Although treatment of opioid dependence is traditionally focused on heroin users, there is increasing recognition that a large number of people become dependent through the use of prescription opioids. The necessity for long-term treatment has also been increasingly recognised. At present, there are several pharmacotherapies available for maintenance treatment, including drugs that are full agonists at the opioid receptor (e.g., methadone, slow-release oral morphine), a partial agonist (buprenorphine) and an opioid antagonist (naltrexone). This review examines the existing strategies, highlights problems associated with their use and discusses the opportunities for new treatment approaches, particularly the use of long-acting formulations.

Imaging Water Dissociation on TiO2(110): Evidence for Inequivalent Geminate OH Groups

Identical regions of partially reduced TiO2(110) surfaces with bridge-bonded oxygen vacancy (BBO(V)) concentrations of approximately 10% ML (1 ML = 5.2 x 10(14) cm(-2)) were imaged using scanning tunneling microscopy (STM) before and after dosing H2O at ambient temperature (approximately 300 K). Atomically resolved images confirm that H2O adsorbs dissociatively on the BBO(V) sites, producing two hydroxyl species, one positioned at BBO(V) and denoted OH(V) and the other, denoted OH(B), formed by protonation at either of the two nearest-neighbor bridge-bonded oxygen atoms. Hydrogen hopping along the [001] direction is observed at ambient temperature, with a strong preference for OH(B) (approximately 10x) hydrogen motion. This powerful imbalance demonstrates the inequality of OH(V) and OH(B) and suggests differences in their charge and/or binding configuration.

Vaccine coverage in England: the impact of health service reorganisation

AIM

To evaluate the impact of reorganisation of the health service and a change in the definition used to collect immunisation coverage statistics on vaccine coverage data in England.

METHODS

Denominator data from the Cover Of Vaccination Evaluated Rapidly (COVER) programme, the national programme for the collection of immunisation coverage statistics, were compared to the Office for National Statistics (ONS) population data; the impact of any discrepancies between the two data sources on vaccine coverage was assessed.

RESULTS

ONS populations were generally larger than COVER populations. This was particularly true for 2002, the year Primary Care Trusts (PCTs) came into existence, suggesting that some children are being missed by the COVER programme. On average, in 1998-2001 around 10,000 children per year (approximately 2%) were lost to the COVER population estimates compared to data from ONS. This increased to around 20,000-40,000 (approximately 3-8%) children in 2002, but decreased again in 2003 to 2000-8000 (approximately 1%) children. Assuming all the "lost" COVER children were vaccinated, vaccine coverage appeared very similar to that seen in the COVER programme for all antigens. However, assuming all the "lost" children were unvaccinated, coverage would be substantially lower for all antigens (range 2.7-3.5%).

DISCUSSION

This analysis provides a quantitative example of how changes such as restructuring of the health service directly impact on public health surveillance. Such changes have potential risks for information and may affect important data used to inform public health policy.

BCL2 gene abnormalities define distinct clinical subsets of follicular lymphoma

AIMS

Follicular lymphoma (FL) arising primarily in the skin has recently been proposed as a distinct entity on the basis of a low incidence of t(14;18)(q32;q21) and bcl-2 expression, with a very high percentage of patients surviving more than 5 years. However, cases of t(14;18)(q32;q21)-positive primary cutaneous FL (PCFL) and examples of t(14;18)(q32;q21)-negative FL at nodal and other extranodal sites, are well documented. The aim of this study was to test the hypothesis that there is a subtype of FL lacking t(14;18)(q32;q21), which preferentially involves certain sites but is not restricted by anatomical location.

METHODS AND RESULTS

A cohort of 47 stage 1 FL was stratified according to the presence or absence of t(14;18)(q32;q21) using conventional cytogenetics, polymerase chain reaction and interphase fluorescence in situ hybridization. Compared with t(14;18)(q32;q21)-positive cases, FL lacking the translocation were less likely to express CD10 or bcl-2 (P<0.01), made up a significantly greater proportion of cases arising at extranodal sites (P<0.001) and had a significantly better overall and disease-specific 5-year survival (P<0.01).

CONCLUSIONS

These results support the concept of a subtype of FL lacking t(14;18)(q32;q21), characterized by low-intensity bcl-2 expression, a predilection for extranodal sites, particularly the skin, and a more favourable outcome than t(14;18)(q32;q21)-positive FL.

Within- and between- subject variability in methadone pharmacokinetics and pharmacodynamics in methadone maintenance subjects

AIMS

To investigate within- and between-subject variability of the pharmacodynamics and pharmacokinetics of (R)- and (S)-methadone in methadone maintenance subjects at steady-state.

METHODS

Six non-holder subjects were studied on three occasions at 7-16 day intervals; doses (20-170 mg/day) remained unchanged. Blood samples and pharmacodynamic data were collected 10-12 times over a 24-h inter-dosing interval. All pharmacodynamic data were expressed as the area under the end-point versus time curve. Using analyses of variance with mixed effects, best estimates were made of the ratio of between- to within-subject variation, with corresponding 95% confidence intervals (CI) for within-subject variation at the average value.

RESULTS

Subjects were relatively consistent between occasions, whereas there was much greater between-subject variability (P < 0.02) for all measures. Estimates of the ratio of between- to within-subject variation ranged from 2.2-12.8 for pharmacodynamic measures, and 1.3-7.9 for pharmacokinetic parameters. For pain, total mood disturbance, withdrawal, pupil size and respiration rate, 95% CI for within-subject measures ranged < or = 2-fold, while this was greater for subjective direct opioid effects (4.2-fold). For CL/F of the active (R)-methadone, the variance ratio was 4.9 (P < 0.0003), with 95% CI for within-subject measures ranging < or = 2-fold. (S)-methadone CL/F demonstrated greater within-subject variability (3.4-fold), possibly contributing to a smaller (2.7; P < 0.0003) ratio of between- to within-subject variance.

CONCLUSIONS

Non-holder methadone maintenance treatment participants appear to respond consistently with respect to pharmacokinetics and pharmacodynamics over a 1-2 month period. Such knowledge may help prescribers to determine whether alternative dosing regimens or treatments might be more appropriate in this population.

Low-temperature preparation of anatase thin films on tantalum

Titanium dioxide thin films were grown on oxidized Ta surfaces using a cyclic layer-by-layer wet chemistry method: successive-ionic-layer-adsorption-and-reaction (SILAR). Film thicknesses varied monotonically and approximately linearly with the number of cycles. As-grown (AG) films were amorphous and rougher (16.2 nm root-mean-square (rms)) than the Ta substrate (10.2 nm rms). After hydrothermal annealing (AN) at a remarkably low temperature of 393 K, the films exhibited anatase crystallites (10 nm dimensions) and reduced roughness (11.8 nm rms). The atomic composition of both AG and AN films was consistent with that of TiO2 containing no more than 4 atom % carbon. A small Si impurity (<1 atom %) was eliminated by using polypropylene beakers and sample holders in the SILAR steps.

Growth and analysis of octadecylsiloxane monolayers on Al2O3 (0001)

On solvent-cleaned and piranha-etched single-crystal Al2O3(0001) surfaces, uniform, robust, self-assembled monolayers of octadecylsiloxane (ODS) are formed by 48 h exposure to a solution containing octadecyltrichlorosilane (OTS) in an anhydrous atmosphere. X-ray photoelectron spectroscopy, atomic force microscopy, ellipsometry, and water contact angle measurements confirm the presence of a uniform, complete monolayer. Reducing the exposure time or omitting the piranha-etch leads to much less uniform coverage. The ODS monolayers are stable when stored in ambient atmospheres for month-long periods. Thermal desorption in a vacuum environment (10(-9) Torr) shows the ODS monolayer is thermally stable up to at least 420 K. When heated in 200 mTorr of flowing forming gas (N2-10% H2) for 1 h at 520 K, slow loss of ODS was indicated. A schematic model is proposed which involves island nucleation by covalent bonding of OTS to surface hydroxyl groups followed by growth through the addition of mobile ODS species.

Fluctuations in (R,S)-methadone pharmacokinetics and response among long-term methadone maintenance patients

Knowledge of how methadone disposition may fluctuate during the course of maintenance treatment is presently limited. This study investigated long-term fluctuations in methadone pharmacokinetics in five methadone maintenance patients who participated in two 24-hour testing sessions separated by at least one year. Results indicated substantial fluctuations between sessions in dose-corrected average steady-state plasma (R)-methadone concentrations (Cav), ranging from a 51% decrease to a 466% increase. These fluctuations were not consistently associated with changes in methadone dose or self-reported withdrawal status. The plasma (S)-:(R)-methadone Cav ratio increased significantly (12%, P = 0.04) between the sessions, suggesting a different pattern of long-term change in the pharmacokinetics of each enantiomer over time. The pronounced and variable fluctuations in methadone disposition evident in these patients highlight the need for an individualized approach to patient dosing and monitoring.