The acute vapour inhalation toxicity of 2-butoxyethanol. Points considered when designing and conducting a study in Guinea pigs and evaluating existing inhalation toxicity data on low volatility solvents.

This publication reports the outcome of an acute inhalation toxicity study with guinea pigs by nose-only exposure to the substance 2-butoxyethanol at exposures close to the maximum attainable saturation vapour concentration. We describe the methods used to ensure exposure only to saturation vapour at a level as high as could be practically achieved whilst avoiding aerosol formation. We consider the practical difficulties and implications of testing substances at or close to their saturation vapour concentration and the criteria that should be used to critically assess such studies, especially with reference to the GHS (Globally Harmonised System) for classification and labelling, where a clear differentiation between gases, vapours and dust and mists applies. Guinea pigs showed no adverse effects when exposed for 4 h to the maximum attainable concentration of pure 2-butoxyethanol vapour. If guinea pigs are regarded as the most appropriate species to assess short term toxicity to humans from exposure to 2-butoxyethanol, because they are like humans not sensitive to haemolysis of red blood cells caused by exposure to the substance, then the data from this study shows that 2-butoxyethanol presents a low acute inhalation toxicity hazard.

Propylene oxide derived glycol ethers: A review of the alkyl glycol ethers potential to cause endocrine disruption.

The 'propylene glycol ethers' (PGEs) are a group of chemical solvents and functional fluids produced through the reaction of propylene oxide (PO) and a monoalcohol. PGEs form different structural isomers, with possible permutations increasing with the number of PO units in the molecule. The dominant isomers have only secondary hydroxyl groups and are not able to be metabolized to the acid structures that are associated with reproductive toxicity. There have been published claims that glycol ethers are human endocrine disruptors. This review systematically evaluates all the available and relevant in vitro and in vivo data across the propylene glycol ether family of substances using an approach based around the EFSA/ECHA 2018 guidance for the identification of endocrine disruptors. The conclusion reached is that there is no evidence to show that PGEs target any endocrine organs or perturb endocrine pathways.

Ethylene oxide derived glycol ethers: A review of the alkyl glycol ethers potential to cause endocrine disruption.

The 'ethylene glycol ethers' (EGE) are a broad family of solvents and hydraulic fluids produced through the reaction of ethylene oxide and a monoalcohol. Certain EGE derived from methanol and ethanol are well known to cause toxicity to the testes and fetotoxicity and that this is caused by the common metabolites methoxy and ethoxyacetic acid, respectively. There have been numerous published claims that EGE fall into the category of 'endocrine disruptors' often without substantiated evidence. This review systematically evaluates all of the available and relevant in vitro and in vivo data across this family of substances using an approach based around the EFSA/ECHA 2018 guidance for the identification of endocrine disruptors. The conclusion reached is that there is no significant evidence to show that EGE target any endocrine organs or perturb endocrine pathways and that any toxicity that is seen occurs by non-endocrine modes of action.

The urinary metabolic profile of diethylene glycol methyl ether and triethylene glycol methyl ether in Sprague-Dawley rats and the role of the metabolite methoxyacetic acid in their toxicity.

Ethylene glycol ethers are a well-known series of solvents and hydraulic fluids derived from the reaction of ethylene oxide and monoalcohols. Use of methanol as the alcohol results in a series of mono, di and triethylene glycol methyl ethers. The first in the series, monoethylene glycol methyl ether (EGME or 2-methoxyethanol) is well characterised and metabolises in vivo to methoxyacetic acid (MAA), a known reproductive toxicant. Metabolism data is not available for the di and triethylene glycol ethers (DEGME and TEGME respectively). This study evaluated the metabolism of these two substances in male rats following single oral gavage doses of 500, 1000 and 2000 mg/kg for DEGME and 1000 mg/kg for TEGME. As for EGME, the dominant metabolite of each was the acid metabolite derived by oxidation of the terminal hydroxyl group. Elimination of these metabolites was rapid, with half-lives <4 h for each one. Both substances were also found to produce small amounts of MAA (~0.5% for TEGME and ~1.1% for DEGME at doses of 1000 mg/kg) through cleavage of the ether groups in the molecules. These small amounts of MAA produced can explain the effects seen at high doses in reproductive studies using DEGME and TEGME.

Acute toxicity classification for ethylene glycol mono-n-butyl ether under the Globally Harmonized System.

Acute oral, dermal and inhalation toxicity classifications of chemicals under the United Nations Globally Harmonized System of Classification and Labelling of Chemicals (GHS) should typically be based on data from rats and rabbits, with the tacit assumption that such characterizations are valid for human risk. However this assumption is not appropriate in all cases. A case in point is the acute toxicity classification of ethylene glycol mono-n-butyl ether (EGBE, 2-butoxyethanol, CAS 111-76-2), where acute toxicity data from rats or rabbits leads to an overly conservative assessment of toxicity. Hemolysis is the primary response elicited in sensitive species following EGBE administration and the proximate toxicant in this response is 2-butoxyacetic acid (BAA), the major metabolite of EGBE. The sensitivity of erythrocytes to this effect varies between species; rats and rabbits are sensitive to BAA-mediated hemolysis, whereas humans and guinea pigs are not. In this publication, a weight of evidence approach for the acute hazard classification of EGBE under GHS is presented. The approach uses acute toxicity data from guinea pigs with supporting mechanistic and pharmacokinetic data in conjunction with human experience and shows that adopting the standard method results in over-classification.

The neural correlates of social anxiety disorder and response to pharmacotherapy.

This study attempted to define further the neural processing events underlying social anxiety in patients with social anxiety disorder (SAD) and their response to pharmacotherapy. Social anxiety-related changes in regional cerebral blood flow were defined by [15O]H2 positron emission tomography (PET) in medication-free individuals with generalized SAD (gSAD), and age- and sex-matched comparison subjects, and analyzed using a linear mixed effects model. PET studies were again acquired in the gSAD individuals following an 8-week, flexible dose treatment trial of nefazodone. Both script-guided mental imagery of an anxiogenic social situation and a confrontational mental arithmetic task were associated with marked increases in self-rated anxiety in both subject groups. For gSAD subjects, social anxiety induced by guided mental imagery was associated with increased activity in the left postcentral gyrus and lenticulate, and the right inferior frontal and middle temporal gyri. Social anxiety induced by the mental arithmetic task was associated with activation of the medial and left dorsolateral prefrontal cortex, cerebellum, thalamus, insula, and ventral striatum. Both tasks were associated with relative decreases in activity in the right amygdala and the hippocampus. A direct group comparison indicated that comparison subjects exhibited a differing pattern of social anxiety-related neural activations. Nefazodone treatment was associated with marked clinical improvement. Comparison of social anxiety-related neural activations prior to and after nefazodone administration indicated greater activity in the precentral gyrus, insula, midbrain/hypothalamus, and middle frontal and anterior cingulate gyrus prior to treatment, and greater activity in the left middle occipital and bilateral lingual gyri, postcentral gyrus, gyrus rectus, and hippocampus after treatment. The results of an analysis relating neural activity and treatment-related changes in symptom severity indicated differential neural responses associated with states of symptom remission vs partial response. The observed social anxiety-related changes in distributed neural activity are consistent with cognitive models of SAD and adaptive decreases in amygdala activity in response to social anxiogenics, and support the association of altered frontal cortical responses with treatment response.

Efficacy of low and higher dose extended-release venlafaxine in generalized social anxiety disorder: a 6-month randomized controlled trial.

RATIONALE: There is a need for new pharmacological treatments for generalized social anxiety disorder (GSAD), which is a common, often disabling condition. OBJECTIVE: To compare the efficacy and safety over 6 months duration of two dose ranges of venlafaxine extended-release (ER) with placebo in patients with GSAD. METHOD: Twenty-eight-week, double-blind, multi-center study in 386 adult outpatients with DSM-IV GSAD. Patients were randomized to placebo, venlafaxine ER fixed low dose (75 mg/day), or venlafaxine ER flexible higher dose (150-225 mg/day). Primary efficacy variable was change on the Liebowitz Social Anxiety Scale (LSAS). Secondary efficacy variables included, among others, the proportion of responders on the CGI Global Improvement Item (score 1 or 2), and the proportion of remitters (defined as an LSAS score of

Achieving remission in major depressive disorder: the first step to long-term recovery.

Major Depressive Disorder (MDD) is a common clinical condition encountered in primary care practices. Left untreated or, more commonly, undertreated, MDD typically results in significant distress and dysfunction. Successful treatment of MDD, usually defined as achieving sustained remission, is an attainable goal. As such, sustained remission should be the goal sought by physicians and patients. A number of variables have an impact on the likelihood of achieving and sustaining remission including the length of the depressive episode, the completeness of the response to treatment, and whether remission is achieved relatively early in treatment. The selection of pharmacotherapeutic agents and the relative probability of achieving remission has only recently been investigated in outpatient populations, though this issue has been explored in inpatient studies for more than a decade. This article reviews these variables and presents strategies with the goal of achieving remission for patients with MDD. The importance of both pharmacotherapy, where indicated, as well as psychotherapy is discussed. Finally, remission is presented as a necessary first step to ensure an optimal long-term outcome, rather than as the final goal of treatment.

Demonstration of the efficacy and safety of a novel substance P (NK1) receptor antagonist in major depression.

The efficacy and safety of a selective NK(1) antagonist, L-759274, was investigated in outpatients with diagnosis of major depressive disorder with melancholic features, following evidence obtained with the novel compound aprepitant that Substance P (NK(1)) antagonists may provide a unique mechanism of antidepressant activity. A randomized, double-blind placebo-controlled study was carried out. Patients, male or female, aged 18-60, scoring >/=25 points on total of first 17 items of 21-item Hamilton Depression Scale (HAMD), and scoring >/=4 (moderately ill) on Clinical Global Impressions-Severity Scale were randomized to oral L-759274 40 mg daily (n=66) or placebo (n=62) for 6 weeks. For patients receiving L-759274, improvement (mean decrease from baseline) in HAMD-17 total score was 10.7 points, compared with a mean 7.8 point improvement in patients receiving placebo (p<0.009). Mean scores for item 1 of HAMD-17 (depressed mood) also improved to a greater extent in the active group compared with the placebo group (0.3 points, p<0.058). Compared with placebo, mean scores on Clinical Global Impressions-Improvement Scale improved significantly by the end of the trial (p=0.009). L-759274 was generally safe and well-tolerated. The incidence of sexual side effects was on par with that observed in patients receiving placebo, and the incidences of gastrointestinal effects were low. Antidepressant actions have now been observed with two different highly selective NK(1) antagonists (aprepitant and L-759274). NK(1) antagonism is a replicated and generally well-tolerated antidepressant mechanism.

Achieving remission in major depressive disorder: the first step to long-term recovery.

Major Depressive Disorder (MDD) is a common clinical condition encountered in primary care practices. Left untreated or, more commonly, undertreated, MDD typically results in significant distress and dysfunction. Successful treatment of MDD, usually defined as achieving sustained remission, is an attainable goal. As such, sustained remission should be the goal sought by physicians and patients. A number of variables have an impact on the likelihood of achieving and sustaining remission including the length of the depressive episode, the completeness of the response to treatment, and whether remission is achieved relatively early in treatment. The selection of pharmacotherapeutic agents and the relative probability of achieving remission has only recently been investigated in outpatient populations, though this issue has been explored in inpatient studies for more than a decade. This article reviews these variables and presents strategies with the goal of achieving remission for patients with MDD. The importance of both pharmacotherapy, where indicated, as well as psychotherapy is discussed. Finally, remission is presented as a necessary first step to ensure an optimal long-term outcome, rather than as the final goal of treatment.

Remission as the goal of treatment in major depressive disorder.

The first step in initiating treatment is to establish the diagnosis, confirming MDD and being careful to rule out BPAD and comorbid anxiety or substance abuse/dependence disorders. Consideration should be given to the pathophysiology of the MDD, recognizing that current technology does not allow its identification in an individual patient. The pathophysiology must be considered in the selection of initial treatment; if an initial treatment has failed, treatment with a medication that has a different or expanded mechanism of action should be considered. Clinicians must also consider the importance of psychotherapy, where indicated, and listen to the feedback of their patients, tempering it with a measure of objectivity. Finally, clinicians must constantly query themselves as to whether there has been sufficient improvement in their patients with depression. It is the willingness to be appropriately aggressive in treating MDD that will ensure a timely, optimal outcome for their patients.

Effect of Hypericum perforatum (St John's wort) in major depressive disorder: a randomized controlled trial.

CONTEXT: Extracts of Hypericum perforatum (St John's wort) are widely used for the treatment of depression of varying severity. Their efficacy in major depressive disorder, however, has not been conclusively demonstrated. OBJECTIVE: To test the efficacy and safety of a well-characterized H perforatum extract (LI-160) in major depressive disorder. DESIGN AND SETTING: Double-blind, randomized, placebo-controlled trial conducted in 12 academic and community psychiatric research clinics in the United States. PARTICIPANTS: Adult outpatients (n = 340) recruited between December 1998 and June 2000 with major depression and a baseline total score on the Hamilton Depression Scale (HAM-D) of at least 20. INTERVENTIONS: Patients were randomly assigned to receive H perforatum, placebo, or sertraline (as an active comparator) for 8 weeks. Based on clinical response, the daily dose of H perforatum could range from 900 to 1500 mg and that of sertraline from 50 to 100 mg. Responders at week 8 could continue blinded treatment for another 18 weeks. MAIN OUTCOME MEASURES: Change in the HAM-D total score from baseline to 8 weeks; rates of full response, determined by the HAM-D and Clinical Global Impressions (CGI) scores. RESULTS: On the 2 primary outcome measures, neither sertraline nor H perforatum was significantly different from placebo. The random regression parameter estimate for mean (SE) change in HAM-D total score from baseline to week 8 (with a greater decline indicating more improvement) was -9.20 (0.67) (95% confidence interval [CI], -10.51 to -7.89) for placebo vs -8.68 (0.68) (95% CI, -10.01 to -7.35) for H perforatum (P =.59) and -10.53 (0.72) (95% CI, -11.94 to -9.12) for sertraline (P =.18). Full response occurred in 31.9% of the placebo-treated patients vs 23.9% of the H perforatum-treated patients (P =.21) and 24.8% of sertraline-treated patients (P =.26). Sertraline was better than placebo on the CGI improvement scale (P =.02), which was a secondary measure in this study. Adverse-effect profiles for H perforatum and sertraline differed relative to placebo. CONCLUSION: This study fails to support the efficacy of H perforatum in moderately severe major depression. The result may be due to low assay sensitivity of the trial, but the complete absence of trends suggestive of efficacy for H perforatum is noteworthy.