Methoxetamine: prevalence of use in the USA and UK and associated urinary problems

Background: Methoxetamine is a novel psychoactive substance and a legal alternative to ketamine in many countries, including parts of the United States. Frequent recreational ketamine use can cause lower urinary tract symptoms, whereas methoxetamine was originally marketed as “bladder friendly”.

Aims: (1) To determine changes in prevalence of methoxetamine use between 2011 and 2012 in the USA and UK and (2) to investigate the prevalence of urinary symptoms in group of methoxetamine users, who had also used ketamine at least once in their lifetime.

Methods: Cross-sectional, anonymous online surveys exploring patterns of drug use were conducted in late 2011 (n?=?15?200) and late 2012 (n?=?22?289).

Results: Reported lifetime, past 12 months, and last month methoxetamine use significantly increased in the USA between 2011 and 2012; whereas, during the same period, past 12 months and last month methoxetamine use significantly decreased in the UK. Of the methoxetamine users questioned in the 2012 survey, 23.0% (n?=?98) reported experiencing urinary symptoms. Prevalence of at least one urinary symptom was related to frequency of methoxetamine use in the last month.

Conclusions: Methoxetamine use appeared to increase in the United States and decrease in the UK between 2011 and 2012. Approximately, one-quarter of methoxetamine users questioned reported urinary symptoms; however, previous ketamine use cannot be ruled out as the cause of the symptoms.     

Alloimmunization to platelet-specific antigens on glycoproteins IIb- IIIa and Ib/IX in multiply transfused thrombocytopenic patients

The rate of alloimmunization to platelet-specific antigens associated with platelet glycoproteins (GPs) IIb-IIIa and Ib/IX was studied in 293 multiply transfused thrombocytopenic patients. Antibodies to platelet-specific antigens were measured with a solid-phase assay using platelet GP IIb-IIIa or Ib/IX as the antigenic targets. Nine patients were found to have antibodies to platelet GP IIb-IIIa, and no patients had antibodies to platelet GP Ib/IX. In six of these nine patients, the specificity of the antibody was shown by using GP IIb-IIIa from donors with different platelet-specific antigen phenotypes. In the remaining three patients with antibodies to platelet GP IIb-IIIa, no specificity could be identified. These patients had autoimmune thrombocytopenia in association with lymphoma. The alloimmunization rate to platelet-specific antigens associated with GP IIb-IIIa was 2 percent, whereas the rate of alloimmunization to HLA antigens was 23 percent. Of the patients alloimmunized to HLA antigens, 9 percent also had antibodies to platelet-specific antigens. A poor response to HLA-identical platelet transfusions was observed only in those patients with positive assays in the solid-phase test. These results suggest that the incidence of antibodies to platelet-specific antigens carried on GP IIb-IIIa is low. Platelet-specific antibodies may be found more frequently in patients alloimmunized to HLA antigens than in those not so alloimmunized.     

Tuberculosis research update

Tuberculosis (TB) remains a major challenge to global public health in the 21st century. In 2007, there were an estimated 9.27 million new cases and 1.3 million deaths among HIV‐negative patients with TB. The HIV‐associated TB epidemic, drug‐resistant disease, the need for better diagnostic assays and the limited efficacy of Bacille Calmette–Guerin vaccination are four important obstacles to further progress in global TB control. In this brief review, we provide a focused update on these four key areas of TB research.     

Antihypertensive efficacy of metoprolol XL/Low dose chlorthalidone (6.25 mg) combination: a randomized,comparative study in Indian patients with mild-to-moderate essential hypertension

Objective

High blood pressure is one of the most important risk factors, directly responsible for increasing the cardiovascular morbidity and mortality. The primary objective was to evaluate the efficacy of metoprolol XL/chlorthalidone against metoprolol XL/hydrochlorothiazide with respect to mean fall in systolic and diastolic blood pressure. The secondary objective was to compare the response rates and to evaluate the tolerability of study medications in patients with mild-tomoderate essential hypertension.

Methods

Total 130 eligible patients (65: metoprolol XL 25 mg/chlorthalidone 6.25 mg; 65: metoprolol XL 25 mg/HCTZ 12.5 mg) were enrolled in this randomized, comparative, multicentric, 12-weeks study. Sixty-two patients from each group completed the study. After 4-weeks of treatment, non-responders from chlorthalidone 6.25 mg combination group were shifted to metoprolol XL 50 mg/chlorthalidone 12.5 mg and non-responders from HCTZ 12.5 mg combination group were escalated to metoprolol XL 50 mg/HCTZ 12.5 mg.

Results

The study treatment groups were comparable with respect to demography and baseline disease characteristics. Both the starting therapies were comparable with respect to mean fall in SBP (p = 0.788) and DBP (p = 0.939), and response rates (p = 1.0) after 4-weeks of therapy. Also both the step-up therapies showed similar mean fall in SBP (p = 0.277) and DBP (p = 0.507) at the end of 12-weeks. However, significantly more number of patients from chlorthalidone 12.5 mg/metoprolol XL 50 mg group responded to therapy as compared to that from HCTZ 12.5 mg/metoprolol XL 50 mg group (p = 0.045). All the reported adverse events were of mild-to-moderate intensity. There were no clinically significant trends in electrolytes (Na⁺, K⁺, Cl^-)and fasting blood sugar, evident across the treatment groups.

Conclusion

Chlorthalidone in combination with metoprolol XL is as effective and well tolerated as widely used combination of metoprolol XL/HCTZ, thus providing an alternative therapeutic option.     

The mental health expert patient: findings from a pilot study of a generic chronic condition self-management programme for people with mental illness

BACKGROUND: Less than optimal outcomes and escalating costs for chronic conditions including mental illness have prompted calls for innovative approaches to chronic illness management. AIMS: This study aimed to test the feasibility and utility of combining a generic, clinician administered and peer-led self-management group approach for people with serious mental illness. METHOD: General practitioners and mental health case managers used a patient-centred care model (the Flinders model) to assist 38 patients with serious mental illness to identify their self-management needs, and match these with interventions including Stanford peer-led, self-management groups and one-to-one peer support. Self-management and quality of life outcomes were measured and qualitative evaluation elicited feedback from all participants. RESULTS: Collaborative care planning, combined with a problems and goals focused approach, resulted in improved self-management and mental functioning at 3 to 6 months follow-up. The Stanford self-management course was applicable and acceptable to patients with serious mental illnesses. Qualitative feedback was highly supportive of this approach. CONCLUSIONS: Generic, structured assessment and care planning approaches, resulting in self-management education targeted to the individual, improved self-management and quality of life. Patients and service providers reported considerable gains despite the challenges associated with introducing a generic model within the mental health and general practice sector.     

Prediction of the effect of erythromycin, diltiazem, and their metabolites, alone and in combination, on CYP3A4 inhibition

Predictive models of complex drug-drug interactions between multiple inhibitors and their metabolites have not been evaluated. The purpose of this study was to evaluate an interaction model for cytochrome P450 3A4 (CYP3A4) that incorporated the simultaneous reversible and irreversible inhibition by multiple inhibitors. Erythromycin (ERY) and diltiazem (DTZ), and their major metabolites, N-desmethylerythromycin (nd-ERY) and N-desmethyldiltiazem (nd-DTZ), were chosen to evaluate the model. k(inact) (rate constant for maximal inactivation), K(I) (inhibitor concentration at 50% maximal inactivation), and K(i) (reversible inhibition constant) were estimated for ERY, DTZ, nd-ERY, and nd-DTZ, respectively, using cDNA-expressed CYP3A4 and human liver microsomes under optimal experimental conditions. To evaluate the interaction model, combinations of inhibitors and metabolites were incubated at concentrations equal to K(I), (1/2)K(I), and 2K(I) of each inhibitor for specified durations in both enzyme systems. The models were further evaluated by the incubation of combinations of inhibitors with the substrate testosterone for 10 min. CYP3A4 inhibition in the presence of drug mixtures was predicted from the inhibition parameters determined for each drug or metabolite alone. The CYP3A4 activity in the presence of multiple inhibitors was well predicted by the model incorporating additive irreversible inhibition as modified by mutual competitive inhibition (percent mean error and percent mean absolute error ranged from -0.06 to 0.04 and from 0.03 to 0.09, respectively). In conclusion, the additive model predicted the combined effect of multiple inhibitors on CYP3A inhibition in vitro. However, simultaneous reversible and irreversible inhibition effects should be taken into account in a reaction mixture of substrate and multiple inhibitors of CYP3A4.