The role of flumazenil in the treatment of benzodiazepine dependence: physiological and psychological profiles

Two-related studies are presented here, detailing our early experience with benzodiazepine-dependent patients treated with a four-day flumazenil infusion using a novel delivery technique. Patients with long-term benzodiazepine dependence who attended the Australian Medical Procedures Research Foundation (AMPRF, Perth, Australia) for treatment were recruited for these studies. Self-reported psychological and physical symptoms, as well as objective vital signs data were collected at intervals before, during and 2 weeks postinfusion. Study A is a case series with cardiovascular measures; study B is an open trial that tracks the psychological profiles of 13 subjects. Withdrawal symptoms were tracked, however, the nature and severity of these symptoms differed between patients. No major complications or discomfort prompting study dropout was observed. Significant benzodiazepine abstinence occurred with this flumazenil infusion method despite high levels of initial dependence, comorbid substance use and comorbid psychiatric illness. Low-dose flumazenil infusion appears to be a safe and effective treatment resulting in withdrawal symptoms of lesser severity than any other cessation method currently available. Recommendations for future research are discussed.

Observation of nonmagnetic resonant scattering effects by tunneling in dilute Al-mn alloy superconductors

We have observed the BCS-like density of states predicted for energy-gap suppression by nonmagnetic Anderson impurities in superconductors. We show that Mn impurities in Al exhibit no magnetic character and act exclusively as strong resonant scattering sites without producing time-reverse symmetry breaking of Cooper pairs (pair breaking).

Achieving long-term continuous blood naltrexone and 6-beta-naltrexol coverage following sequential naltrexone implants

The aim of this study was to assess blood free naltrexone and 6-beta-naltrexol levels with time following treatment with sequential sustained-release naltrexone preparations. Data were collected from blood samples analysed independently for naltrexone and 6-beta-naltrexol and from clinical record review at a community heroin treatment clinic in Perth, Western Australia. Five patients received sequential 3.4 g (3.49+/-0.01 g and 3.36+/-0.05 g, respectively) naltrexone implants. The second implant was received on average within 131.2+/-15.67 days of the first implant. The mean length of follow-up was 307.2+/-18.28 days of the first implant. Blood naltrexone levels have the potential to remain above 2 and 1 ng/ml for a total of 390 and 524 days, respectively, and blood 6-beta-naltrexol was maintained above 10 ng/ml for a total of 222 days following insertion of these implants. No patient relapsed to dependent heroin use during the implant coverage period while blood naltrexone concentrations were above 2 ng/ml. Results indicate that blood naltrexone and 6-beta-naltrexol levels can be maintained above therapeutic levels for prolonged periods following use of sequential 3.4 g naltrexone implants. These extended periods of coverage will offer significant benefits for managing the heroin-dependent patient.

Blood naltrexone and 6-beta-naltrexol levels following naltrexone implant: comparing two naltrexone implants

The aim of this study was to profile and compare blood naltrexone and 6-beta-naltrexol levels with time following treatment with two sustained-release naltrexone preparations produced by GoMedical Industries, Australia at a community heroin treatment clinic in Perth, Western Australia. A sample of 10 patients who each received a 1.7 g naltrexone implant were compared to 24 patients who each received a 3.4 g naltrexone implant as treatment for heroin dependence. Blood naltrexone levels following treatment with the 1.7 g naltrexone implant remained above 2 and 1 ng/ml for approximately 90 and 136 days, respectively. Use of the 3.4 g naltrexone implant extended the period of coverage to approximately 297 (1 ng/ml) or 188 (2 ng/ml) days. Blood 6-beta-naltrexol levels remained above 10 ng/ml for approximately 18 and 83 days, respectively, following use of the 1.7 g and 3.4 g naltrexone implants. The current study data indicate that blood naltrexone and 6-beta-naltrexol levels following treatment with either the 1.7 g or 3.4 g naltrexone implant are greater than those reported in other published data on other sustained-release naltrexone preparations. Furthermore, duration of blood naltrexone and 6-beta-naltrexol levels achieved following use of the 3.4 g implant were superior to those achieved with the 1.7 g naltrexone implant, with naltrexone blood levels maintained above 2 ng/ml for a period of approximately 6.3 months compared to 3 months, respectively. The implications of this in managing the heroin-dependent patient, especially those who find it difficult to shift away from dependent use patterns, are discussed.

Use of oral and implantable naltrexone in the management of the opioid impaired physician

Doctors are at an increased risk for prescription drug use, particularly opioids and benzodiazpines. This use can interfere with work function and has major potential negative implications for patient safety. Oral naltrexone, an opioid antagonist, has been used as part of a management strategy for opioid dependent physicians. While some patients stabilize on oral naltrexone, others relapse to opioid use. An alternative method of naltrexone maintenance involves the injection or surgical insertion of a sustained release preparation of naltrexone. This approach dramatically improves compliance, removing the onus from the previously opioid impaired physician to use daily oral naltrexone. This article describes the cases of four opioid-impaired doctors who received naltrexone (either oral or implant) as part of their management. The authors conclude that monitoring daily oral naltrexone use and detecting early opioid relapse is difficult, placing both the opioid impaired physician and their patients at risk. In contrast, by using implantable naltrexone, compliance is assured and opioid abstinence can virtually be guaranteed for five months. It is argued that naltrexone implants offer a level of protection not achieved with any previous treatment. It is recommended that management should involve early and close collaboration between the treating doctor and the Medical Board, with initial treatment, ongoing monitoring and follow-up being a Medical Board requirement for registration.

Using naltrexone implants in the management of the pregnant heroin user

OBJECTIVES

To describe the case history and associated obstetric and neonatal outcomes of eight women who had their heroin dependency managed over pregnancy by naltrexone implant (two x 1.8 g of naltrexone embedded in poly-DL-lactide acid) treatment.

METHOD

Case data on maternal management associated with naltrexone implant were collected at the Australian Medical Procedures Research Foundation, Perth, Australia and three Perth hospitals.

RESULTS

Despite earlier instability on oral naltrexone and repeated relapses back to dependent heroin use these women, following treatment with naltrexone implant, remained heroin free throughout their pregnancies. Neonatal and obstetric outcomes were unremarkable.

CONCLUSIONS

This case series provides preliminary evidence that the pregnant heroin user can be managed by naltrexone implant without obvious risk to the mother or developing foetus. Importantly, the current case series suggests that the pregnant woman who finds it difficult to stabilise on oral naltrexone maintenance and returns to dependent heroin use may be managed using implantable naltrexone, thereby removing from her the onus for daily naltrexone medication compliance. The authors conclude that naltrexone implant may represent an important procedure for managing the pregnant heroin dependent patient who finds it difficult to shift away from her heroin use patterns. These preliminary findings require confirmation using a much larger controlled study.

Multicenter evaluation of epidemiological typing of methicillin-resistant Staphylococcus aureus strains by repetitive-element PCR analysis. The European Study Group on Epidemiological Markers of the ESCMID

Rapid and efficient epidemiologic typing systems would be useful to monitor transmission of methicillin-resistant Staphylococcus aureus (MRSA) at both local and interregional levels. To evaluate the intralaboratory performance and interlaboratory reproducibility of three recently developed repeat-element PCR (rep-PCR) methods for the typing of MRSA, 50 MRSA strains characterized by pulsed-field gel electrophoresis (PFGE) (SmaI) analysis and epidemiological data were blindly typed by inter-IS256, 16S-23S ribosomal DNA (rDNA), and MP3 PCR in 12 laboratories in eight countries using standard reagents and protocols. Performance of typing was defined by reproducibility (R), discriminatory power (D), and agreement with PFGE analysis. Interlaboratory reproducibility of pattern and type classification was assessed visually and using gel analysis software. Each typing method showed a different performance level in each center. In the center performing best with each method, inter-IS256 PCR typing achieved R = 100% and D = 100%; 16S-23S rDNA PCR, R = 100% and D = 82%; and MP3 PCR, R = 80% and D = 83%. Concordance between rep-PCR type and PFGE type ranged by center: 70 to 90% for inter-IS256 PCR, 44 to 57% for 16S-23S rDNA PCR, and 53 to 54% for MP3 PCR analysis. In conclusion, the performance of inter-IS256 PCR typing was similar to that of PFGE analysis in some but not all centers, whereas other rep-PCR protocols showed lower discrimination and intralaboratory reproducibility. None of these assays, however, was sufficiently reproducible for interlaboratory exchange of data.

Impact of correlated factors on bone density in individuals with a family history of osteoporosis

Previous studies have suggested that 14-47% of the variation in bone mineral density (BMD) can be predicted using clinical risk factors. The aim of our study was to determine, for the first time, the importance of these factors in individuals with evidence of a genetic predisposition to the disease. The subjects studied were 147 female and 86 male Caucasians, all with a family history of osteoporosis. Linear regression was used to determine whether age, height, weight, and years of reduced estrogen exposure were significant predictors of BMD. Males and females were examined separately, and BMD was measured at the hip and spine. The results show that these risk factors, known to be at work in the general population, are equally important in those with a family history of osteoporosis. It is clear, therefore, that they must be taken into account, and corrected for in genetic studies of the disease.

Histological changes associated with long-term urethral stents

OBJECTIVE

To assess the histological changes found in patients with long-term external sphincter, prostatic and urethral stents.

PATIENTS AND METHODS

Eighteen patients with long-term stents (mean time since insertion 3.5 years) were investigated. Three had external sphincter stents for detrusor-sphincter dyssynergia secondary to spinal injury, eight had prostatic stents for obstruction secondary to benign prostatic hyperplasia and seven had urethral stents for recurrent strictures. Nine stents were occluded at investigation, of which seven were entirely removed. The mucosae overlying the remaining two were biopsied, as were mucosae over the nine patent stents, at urethroscopy.

RESULTS

The changes observed included polypoid hyperplasia (11 of 18 patients) between and around the stent mesh wires, nonkeratinizing squamous metaplasia (two) or hyperkeratotic squamous metaplasia (seven), chronic inflammation (15) with prominent plasma cell infiltrates (11), variable foreign-body granuloma (two) and microabscess formation (five), usually associated with clefts formed around the stent wires (three of five).

CONCLUSION

Stents become incorporated into the urethral wall by a process of polypoid hyperplasia through the stent mesh, with at least focal covering of the stent in most cases, and with variable inflammatory infiltrates, most of which are rich in plasma cells. The urothelial and connective tissue proliferation resulted in obstruction of the stent lumen in nine of the patients studied. Further long-term study is necessary to exclude the development of carcinoma in patients with keratinizing squamous metaplasia, although no malignancy was seen in this study.

Acute effects of cyclosporin and cremophor EL on endothelial function and vascular smooth muscle in the isolated rat heart

We studied the effects of cyclosporin dissolved in the vehicle used as an intravenous preparation, namely, cremophor EL, and cremophor alone on the basal coronary flow plus endothelial function and vascular smooth muscle response by examining their influence on 5-hydroxytryptamine (5-HT) and nitroglycerine (GTN) induced the changes in coronary flow in the isolated rat heart. A total of 72 rat hearts were perfused with a modified Langendorf preparation. There was a 12.8 +/- 3% reduction in the basal coronary flow after 60 minutes of perfusion with the drug-free buffer (p = ns). A dose of 50 ng/ml of cremophor or cyclosporin gave a similar reduction in the flow (cremophor 9.2 +/- 0.7%, cyclosporin 12.7 +/- 2%). However, at higher concentrations cremophor caused dose-dependent coronary vasodilation, while cyclosporin had the opposite effect. The maximum effect after 1000 ng/ml of cyclosporin was a 48.7 +/- 0.6% decrease, and after an equivalent dose of cremophor a 24.8 +/- 2.2% increase in the flow. The vasodilatory response to 5-HT and GTN remained unchanged after 60 minutes of perfusion with the drug-free buffer (5-HT, before 33.3 +/- 2.5%, after 37.7 +/- 4.2%; GTN, before 34.3 +/- 2.5%, after 33.7 +/- 1.5%).(ABSTRACT TRUNCATED AT 250 WORDS)

The influence of patient insemination on the implantation rate in an in vitro fertilization and embryo transfer program

The implantation rates and subsequent pregnancy rates in in vitro fertilization (IVF) programs are lower than those currently seen in the normal fertile population. During IVF treatment regimens, intercourse is not allowed and artificial insemination is normally excluded. This trial, involving the deposition of semen in the high vaginal area, was undertaken for evaluation of the influence of sperm in the reproductive tract on subsequent implantation rates. The results show that the implantation rate, as assessed by a rise in the human chorionic gonadotropin levels in inseminated patients, was 53%, compared with 23% in the control group. The implantation rate of 54% in the group who had tubal occlusion or no fallopian tubes was not significantly different from the implantation rate of 50% in the group with patent tubes, which suggests that the site of sperm influence was on the endometrium and that the absence of the fallopian tube has no significant effect upon this influence.