Relative Temperature Maximum in Wound Infection and Inflammation as Compared with a Control Subject Using Long-Wave Infrared Thermography.

OBJECTIVE: The purpose of this retrospective case series was to determine whether a long-wave infrared thermography (LWIT, or thermal imaging) camera can detect specific temperature changes that are associated with wound infection and inflammation as compared with normal control subjects with similar anatomical wound locations. DESIGN: A retrospective, observational, collective, multiple case series of patients who underwent digital and thermal imaging of wounds in various states. SETTING: The subjects were selected from multiple sites including an outpatient wound care clinic, a wound care physician's office, a rehabilitation hospital, and a home healthcare organization. PATIENTS: Six subjects were selected for inclusion, including 2 each for the infection, inflammation, and normal control groups. MAIN OUTCOME MEASURE: The study collected relative temperature maximums as obtained and recorded by LWIT and digital imaging. MAIN RESULTS: In this case series, the authors demonstrate the use of an FDA-approved Scout (WoundVision, Indianapolis, Indiana) dual-imaging long-wave infrared and digital cameras to analyze images of wounds. In the 2 cases with clinically diagnosed wound infection, LWIT showed an elevation of temperature as evidenced by a maximum temperature differential between the wound and healthy skin of +4° C to 5° C. Also, LWIT was able to identify relative thermal changes of +1.5° C to 2.2° C in subjects presenting with clinical signs of inflammation. In addition, LWIT was able to show that the normal control subjects without diagnosis of infection or signs of inflammation had relative temperature differentials of +1.1° C to 1.2° C. Finally, LWIT could detect adequate treatment of infected wounds with antibiotics as evidenced by a return to normal temperature differences gradient of +0.8° C to 1.1° C, as compared with normal control subjects with wounds in the same anatomical location. CONCLUSIONS: Long-wave infrared thermography can collect and record objective data, including relative temperature maximums associated with infection, inflammation, and normal healing wounds.

Clinical evaluation of pazopanib eye drops in healthy subjects and in subjects with neovascular age-related macular degeneration.

PURPOSE: To evaluate pazopanib 10 mg/mL eye drops (pazopanib) in healthy subjects and in subjects with previously untreated subfoveal choroidal neovascularization secondary to age-related macular degeneration. METHODS: Study 1 (single center, randomized, placebo-controlled, double-masked) included 3 cohorts of 12 to 13 healthy subjects each who instilled pazopanib or placebo 4 times daily for 2 weeks. Study 2 (multicenter open-label) included 19 subjects with neovascular age-related macular degeneration who instilled pazopanib 4 times daily for 12 weeks. Both studies evaluated pharmacokinetics and safety. Study 2 also evaluated efficacy. RESULTS: Steady-state concentrations of pazopanib in plasma seemed to be reached by Week 2. At Week 4 (Study 2), there were no meaningful changes from baseline in the mean central retinal thickness (37.9 µm) or best-corrected visual acuity (0.1 letters) (primary endpoint), retinal morphology, choroidal neovascularization size, or total lesion size. Complement Factor H genotype had no effect on changes from baseline in the best-corrected visual acuity or central retinal thickness. The most common pazopanib-related ocular adverse events included eye irritation (Study 1, n = 7) and instillation site pain (Study 2, n = 3). No serious adverse events were reported. CONCLUSION: Pazopanib was well tolerated. In subjects with previously untreated neovascular age-related macular degeneration, pazopanib instilled 4 times daily as monothereapy did not seem to improve the best-corrected visual acuity or decrease the central retinal thickness.

Multidimensional measurement within adult protective services: design and initial testing of the tool for risk, interventions, and outcomes.

This study describes the development, field utility, reliability, and validity of the multidimensional Tool for Risk, Interventions, and Outcomes (TRIO) for use in Adult Protective Services (APS). The TRIO is designed to facilitate consistent APS practice and collect data related to multiple dimensions of typical interactions with APS clients, including the investigation and assessment of risks, the provision of APS interventions, and associated health and safety outcomes. Initial tests of the TRIO indicated high field utility, social worker "relevance and buy-in," and inter-rater reliability. TRIO concurrent validity was demonstrated via appropriate patterns of TRIO item differentiation based on the type of observed confirmed abuse or neglect; and predictive validity was demonstrated by prediction of the risk of actual APS recurrence. The TRIO is a promising new tool that can help meet the challenges of providing and documenting effective APS practices and identifying those at high risk for future APS recurrence.

Exposure to insulating materials and risk of coronary artery diseases: a cross-sectional study.

Background: Although previous reports link exposure to insulating materials with an increased risk of mesothelioma and chronic respiratory diseases, studies evaluating their associations with the risk of coronary artery diseases (CAD) are lacking. Aims: We aimed at evaluating the associations between exposure to insulating materials and the 10-year risk of CAD among insulators. Methods: In this cross-sectional study, we recruited 643 adults (≥18 years), full-time insulators from the Local 110 Heat and Frost Insulators and Allied Workers Union in Edmonton, Alberta. We obtained demographic information, personal and family history, and job-exposure history, including experience (years) and types of exposure to insulating materials. Clinical profiling including Framingham risk scores (FRS) was assessed. Results: Of all insulators, 89% were men (mean ± SD age: 47 ± 12 years), 27% had a parental history of cardiac diseases, and 22% had a comorbid chronic respiratory disease. In total, 53% reported exposure to asbestos, while 61, 82, and 94% reported exposure to ceramic fibers, fiberglass, and mineral fibers, respectively. In single-exposure multivariable regression models adjusted for experience, marital status, and body mass index (BMI), asbestos was found to be associated with higher FRS (ß: 1.004; 95%CI: 0.003-2.00). The association remained consistent in multi-exposure models and a higher association was found between asbestos exposure and FRS among insulators with comorbid chronic respiratory disease. Conclusion: Our study demonstrates that apart from cancer and chronic respiratory diseases, asbestos exposure may also have a cardiac effect, thus warranting the need for systematic surveillance to protect workers from the adverse effects of these materials.

COVID-19 infodemic and health-related quality of life in patients with chronic respiratory diseases: A multicentre, observational study.

Background: The explosion of information, misinformation and disinformation (the "infodemic") related to the coronavirus disease 2019 (COVID-19) pandemic on digital and social media is reported to affect mental health and quality of life. However, reports assessing the COVID-19 infodemic on health-related quality of life (HRQL) in patients with chronic diseases are scarce. In this study, we investigated the associations between the infodemic and HRQL in uninfected individuals with pre-existing chronic respiratory diseases (CRDs) such as asthma, chronic obstructive pulmonary disease (COPD) and other CRDs. Methods: We conducted a multi-national, cross-sectional, observational study in Canada, India, New Zealand and the United Kingdom where we distributed a set of digitised questionnaires among 1018 participants with chronic respiratory diseases who were not infected with the SARS-CoV-2 virus at least three months prior to the study. We collected information about the infodemic such as news watching or social media use more than usual during the pandemic. HRQL was assessed using the short form of the chronic respiratory questionnaire (SF-CRQ). Demographic information, comorbidities, compliance, mental health, behavioural function, and social support were also recorded. We analysed the direct and indirect relationships between infodemic and HRQL using structural equation models (SEM). Results: Of all participants, 54% were females and had a mean (standard deviation (SD)) age of 53 (17) years. We found that higher infodemic was associated with worse emotional function (regression coefficient ß = -0.08; 95% confidence interval (CI) = -0.14 to -0.01), which means a one SD change of the higher infodemic latent variable was associated with a 0.08 SD change of emotional function level. The association between higher infodemic and worse emotional function was mediated by worse mental health and behavioural functions but is marginally ameliorated by improved social support. In stratification analysis, we found significant disease and country-wise variations in the associations between infodemic and SF-CRQ domain scores. Conclusions: These results provide new evidence that the COVID-19 infodemic significantly influences the HRQL in patients with CRDs through a complex interplay between mental health, behavioural function, and social support. This new dimension of research also opens avenues for further research on infodemic-related health effects in other chronic diseases.

Less Social Deprivation Is Associated With Better Health-Related Quality of Life in Asthma and Is Mediated by Less Anxiety and Better Sleep Quality.

BACKGROUND: Previous studies on health-related quality of life (HRQoL) in asthma have mainly focused on clinical and environmental determinants. Little is known about the role of social determinants on HRQoL in asthma. OBJECTIVES: We aimed to investigate the association between social deprivation and HRQoL in asthma. METHODS: A total of 691 adult asthmatics from Canada, India, New Zealand, and the United Kingdom were administered a digital questionnaire containing demographic information and questions about social and psychological attributes, sleep disturbances, and alcohol abuse. HRQoL was measured using the Short Form of the Chronic Respiratory Questionnaire (SF-CRQ). We analyzed the direct and indirect relationships between social deprivation and HRQoL using structural equation models with social deprivation as a latent variable. We tested for mediation via anxiety, depression, sleep disturbances, and alcohol abuse. RESULTS: We found that less social deprivation (latent variable) was directly associated with better SF-CRQ domain scores such as dyspnea (regression coefficient ß: 0.33; 95% confidence interval [CI]: 0.07 to 0.58), fatigue (ß: 0.39; 95% CI: 0.14 to 0.64), and emotional function (ß: 0.37; 95% CI: 0.11 to 0.62), but with the worse mastery score (ß: -0.29; 95% CI: -0.55 to -0.03); however, those associations varied across participating countries. We also observed that among all individual social deprivation indicators, education, companionship, emotional support, instrumental support, and social isolation were directly associated with HRQoL, and the relationship between social deprivation and HRQoL was mediated through anxiety and sleep disturbances. CONCLUSIONS: Our results demonstrated that less social deprivation was directly, and indirectly through less anxiety and better sleep quality, associated with better HRQoL in asthma.

Resource seeking strategies of zoosporic true fungi in heterogeneous soil habitats at the microscale level.

Zoosporic true fungi have frequently been identified in samples from soil and freshwater ecosystems using baiting and molecular techniques. In fact some species can be components of the dominant groups of microorganisms in particular soil habitats. Yet these microorganisms have not yet been directly observed growing in soil ecosystems. Significant physical characteristics and features of the three-dimensional structures of soils which impact microorganisms at the microscale level are discussed. A thorough knowledge of soil structures is important for studying the distribution of assemblages of these fungi and understanding their ecological roles along spatial and temporal gradients. A number of specific adaptations and resource seeking strategies possibly give these fungi advantages over other groups of microorganisms in soil ecosystems. These include chemotactic zoospores, mechanisms for adhesion to substrates, rhizoids which can penetrate substrates in small spaces, structures which are resistant to environmental extremes, rapid growth rates and simple nutritional requirements. These adaptations are discussed in the context of the characteristics of soils ecosystems. Recent advances in instrumentation have led to the development of new and more precise methods for studying microorganisms in three-dimensional space. New molecular techniques have made identification of microbes possible in environmental samples.

The Effects of Nitrogen and Phosphorus on Colony Growth and Zoospore Characteristics of Soil Chytridiomycota.

The Chytridiomycota phylum contributes to nutrient cycling and the flow of energy between trophic levels in terrestrial and aquatic ecosystems yet remains poorly described or absent from publications discussing fungal communities in these environments. This study contributes to the understanding of three species of soil chytrids in vitro-Gaertneriomyces semiglobifer, Spizellomyces sp. and Rhizophlyctis rosea-in the presence of elevated concentrations of nitrogen and phosphorus and with different sources of nitrogen. Colony growth was measured after 4 weeks as dry weight and total protein. To determine the impacts on zoospore reproduction, motility, lipid content, and attachment to organic substrates, 4- and 8-week incubation times were investigated. Whilst all isolates were able to assimilate ammonium as a sole source of nitrogen, nitrate was less preferred or even unsuitable as a nutrient source for G. semiglobifer and R. rosea, respectively. Increasing phosphate concentrations led to diverse responses between isolates. Zoospore production was also variable between isolates, and the parameters for zoospore motility appeared only to be influenced by the phosphate concentration for Spizellomyces sp. and R. rosea. Attachment rates increased for G. semiglobifer in the absence of an inorganic nitrogen source. These findings highlight variability between the adaptive responses utilised by chytrids to persist in a range of environments and provide new techniques to study soil chytrid biomass and zoospore motility by total protein quantification and fluorescent imaging respectively.

Chronic effects of occupational exposure to mineral fibres and recurrent chest infections in insulators.

Exposure to mineral fibres (man-made forms of vitreous fibres often used as insulating material) is a risk factor for recurrent chest infections among workers, underscoring the necessity of workplace surveillance for protection from hazardous substances https://bit.ly/38cUpmA.

Therapy Dogs in Educational Settings: Guidelines and Recommendations for Implementation.

Therapy dogs in educational settings have gained increase traction in recent years. Despite its potential benefits and popularity, there remain concerns of perceived risks such as sanitation, allergies, and safety issues, as well as a lack of guidelines, regulations and support resources available to school staff. Research is further lacking into the implementation process of therapy dog programs in educational settings. To construct a set of recommendations for school staff to achieve successful implementation of a therapy dog program, the present study investigated the perceived facilitative and impeding factors when implementing a therapy dog program. A total of 13 school staff and 2 coordinators from therapy dog organisations took part in an open-ended online survey and/or a semi-structured interview over the phone, with the aim of gathering their perspectives of implementing a therapy dog program in schools. The thematic analysis of the data indicated facilitative factors such as program flexibility, whole-school support, the need for communication and training for all staff, as well as dog welfare. Successful implementation of therapy dogs in an education setting appear to revolve around (1) flexibility of the dog therapy program to target school's needs, (2) qualities of program instigator, (3) whole-school support, (4) communication, training and education, (5) considerations for dog's welfare. Key barriers identified included a high workload, lack of guidelines on processes, lack of support from the school community, as well as the need for better understanding of the role of a therapy dog. The results highlighted the importance of a whole-school effort when implementing a therapy dog program, as well as the need for guidelines for assessing school readiness, key factors for consideration, and strategies to overcome challenges associated with program implementation.

Short-Term Acute Exposure to Wildfire Smoke and Lung Function among Royal Canadian Mounted Police (RCMP) Officers.

The increasing incidence of extreme wildfire is becoming a concern for public health. Although long-term exposure to wildfire smoke is associated with respiratory illnesses, reports on the association between short-term occupational exposure to wildfire smoke and lung function remain scarce. In this cross-sectional study, we analyzed data from 218 Royal Canadian Mounted Police officers (mean age: 38 ± 9 years) deployed at the Fort McMurray wildfires in 2016. Individual exposure to air pollutants was calculated by integrating the duration of exposure with the air quality parameters obtained from the nearest air quality monitoring station during the phase of deployment. Lung function was measured using spirometry and body plethysmography. Association between exposure and lung function was examined using principal component linear regression analysis, adjusting for potential confounders. In our findings, the participants were predominantly male (71%). Mean forced expiratory volume in 1 s (FEV1), and residual volume (RV) were 76.5 ± 5.9 and 80.1 ± 19.5 (% predicted). A marginal association was observed between air pollution and higher RV [ß: 1.55; 95% CI: -0.28 to 3.37 per interquartile change of air pollution index], but not with other lung function indices. The association between air pollution index and RV was significantly higher in participants who were screened within the first three months of deployment (2.80; 0.91 to 4.70) than those screened later (-0.28; -2.58 to 2.03), indicating a stronger effect of air pollution on peripheral airways. Acute short-term exposure to wildfire-associated air pollutants may impose subtle but clinically important deleterious respiratory effects, particularly in the peripheral airways.

Effects of rifampicin (rifampin) on the pharmacokinetics and safety of ambrisentan in healthy subjects: a single-sequence, open-label study.

BACKGROUND: Ambrisentan is a once-daily, endothelin (ET) type A receptor-selective antagonist approved for the treatment of pulmonary arterial hypertension. Ambrisentan is primarily metabolized by glucuronidation and undergoes cytochrome P450 (CYP)-mediated oxidation to a lesser extent. OBJECTIVE: To assess the effects of rifampicin (rifampin), a potent inducer of CYP3A4 and inhibitor of organic anion transporter polypeptides (OATPs), on the steady-state pharmacokinetics, safety and tolerability of ambrisentan. METHODS: This was a 14-day, single-sequence, open-label study that was conducted in 24 healthy adults. Subjects were administered oral doses of ambrisentan (10 mg) once daily on days 1 through 5 and were then co-administered ambrisentan (10 mg) plus rifampicin (600 mg) once daily on days 6 through 13. The steady-state pharmacokinetics of ambrisentan and its oxidative metabolite 4-hydroxymethyl ambrisentan were determined in the absence and presence of repeated administration of rifampicin. The main outcome measure was the analysis of ambrisentan pharmacokinetics (area under the plasma concentration-time curve during a dosage interval [AUC(τ)], maximum plasma drug concentration [C(max)] and minimum plasma drug concentration [C(min)]) for steady-state ambrisentan alone (day 5) as compared with steady-state ambrisentan plus steady-state rifampicin (day 13). Adverse events (AEs), ECG recordings, vital signs and clinical laboratory parameters were monitored throughout the study and at follow-up. RESULTS: A transient increase (+87% [95% CI 79, 95]) in ambrisentan steady-state systemic exposure (AUC(τ)) was observed during the first 2 days of rifampicin co-administration. However, in the presence of steady-state rifampicin, ambrisentan C(max) and AUC(τ) values were similar (+2% [95% CI -7, 12] and -4% [-9, 2], respectively) to those observed for ambrisentan alone. Relative systemic exposure of 4-hydroxymethyl ambrisentan was unaffected by either acute or steady-state rifampicin. No serious AEs or AEs leading to withdrawal were reported and there were no clinically significant changes in vital signs, ECG recordings or clinical laboratory parameters with co-administration of ambrisentan and rifampicin. CONCLUSION: Steady-state rifampicin had no clinically relevant effects on the steady-state pharmacokinetics of ambrisentan. The overall safety profile of ambrisentan was similar in the presence and absence of rifampicin. No dose adjustment of ambrisentan should be required when it is co-administered with rifampicin, a strong inducer of CYP3A4 activity and inhibitor of OATPs.

Divergent models of diabetes among American Indian elders.

The purpose of this study was to examine belief systems about diabetes in American Indian elders, and the effects of culture on care-seeking, adherence, and diabetes self-care. Health belief theory predicts that care-seeking and medical adherence are a function of culturally mediated beliefs that result in behaviors that effect health status. In order to elicit cultural meanings of diabetes, in-depth interviews were conducted with an intensity sample of 30 American Indian diabetic elders (55+). Two models of diabetes were identified, divergent in terms of 1) health behaviors, and 2) cultural identification. One model was characterized by delayed care-seeking, and a non-valuing of adherence to diabetes self-care. Non-adherence to medical recommendations was perceived as being socially desirable, because adherence placed the elder outside their peer group. The second model was characterized by early care-seeking and improved adherence to diabetes self-care. These divergent models of diabetes, in which care-seeking, diabetes self-care, and adherence vary as a function of cultural immersion, has implications for health education and disease management and may contribute substantially to health disparities.

Non-Malignant Respiratory Illnesses in Association with Occupational Exposure to Asbestos and Other Insulating Materials: Findings from the Alberta Insulator Cohort.

Many insulating materials are used in construction, although few have been reported to cause non-malignant respiratory illnesses. We aimed to investigate associations between exposures to insulating materials and non-malignant respiratory illnesses in insulators. In this cross-sectional study, 990 insulators (45 ± 14 years) were screened from 2011-2017 in Alberta. All participants underwent pulmonary function tests and chest radiography. Demographics, work history, and history of chest infections were obtained through questionnaires. Chronic obstructive pulmonary disease (COPD) was diagnosed according to established guidelines. Associations between exposures and respiratory illnesses were assessed by modified Poisson regression. Of those screened, 875 (88%) were males. 457 (46%) participants reported having ≥ 1 chest infection in the past 3 years, while 156 (16%) were diagnosed with COPD. In multivariate models, all materials (asbestos, calcium silicate, carbon fibers, fiberglass, and refractory ceramic fibers) except aerogels and mineral fibers were associated with recurrent chest infections (prevalence ratio [PR] range: 1.18-1.42). Only asbestos was associated with COPD (PR: 1.44; 95% confidence interval [CI]: 1.01, 2.05). Therefore, occupational exposure to insulating materials was associated with non-malignant respiratory illnesses, specifically, recurrent chest infections and COPD. Longitudinal studies are urgently needed to assess the risk of exposure to these newly implemented insulation materials.

Effect of ketoconazole on the pharmacokinetic profile of ambrisentan.

Ambrisentan is an endothelin type A (ET(A))-selective receptor antagonist that is metabolized primarily by glucuronidation but also undergoes oxidative metabolism by CYP3A4. The potential for ketoconazole, the archetypal strong inhibitor of CYP3A4, to alter the pharmacokinetic profile of ambrisentan and its oxidative metabolite, 4-hydroxymethyl ambrisentan, was assessed in an open-label, nonrandomized, 2-period, single-sequence study in 16 healthy men. Participants received a single dose of ambrisentan 10 mg alone and after 4 days of ketoconazole 400 mg administered once daily. In the presence of multiple doses of ketoconazole, single-dose ambrisentan AUC(0-infinity) estimate was increased by 35.3%, whereas C(max) was increased by 20.0%. For the 4-hydroxymethyl ambrisentan metabolite, AUC(0-infinity) estimate was decreased by 4.0%, whereas C(max) was decreased by 16.5%. Concomitant administration of ambrisentan and ketoconazole was well tolerated. In summary, ketoconazole had no clinically significant effect on the pharmacokinetics or safety profile of ambrisentan; therefore, no changes in ambrisentan dose should be necessary when the drug is administered concomitantly with known CYP3A4 inhibitors.

Ethanol does not alter the pharmacokinetic profile of the controlled-release formulation of carvedilol.

The concomitant ingestion of alcohol may alter the release of a drug from a modified-release dosage form, posing a potential risk to patients. In a randomized, open-label, 4-period cross-over study, the pharmacokinetic profiles of R(+) and S(-) carvedilol were compared after a single oral dose of carvedilol controlled-release formulation (administered following a standard meal) was given alone or concomitantly with ethanol. Thirty-nine healthy subjects participated in this study. Following coadministration of carvedilol controlled-release 40 mg with ethanol (approximately 38 g), ethanol ingestion 2 hours before or 2 hours after carvedilol controlled-release administration, area under the curve for the R(+) and S(-) carvedilol enantiomers was similar compared with carvedilol controlled-release given alone. Carvedilol exposure was not affected by the concomitant administration of ethanol and carvedilol controlled-release. Maximum plasma concentrations for the R(+) and S(-) carvedilol enantiomers were similar except when ethanol was ingested 2 hours after carvedilol controlled-release administration, where there was a modest decrease in maximum plasma concentration for R(+) and S(-) carvedilol (16% and 17%, respectively). Carvedilol controlled-release given alone or concomitantly with ethanol ingestion was generally well tolerated, and no serious or severe adverse events were reported. Ethanol did not alter the pharmacokinetic profile of carvedilol controlled-release.

Key Ecological Roles for Zoosporic True Fungi in Aquatic Habitats.

The diversity and abundance of zoosporic true fungi have been analyzed recently using fungal sequence libraries and advances in molecular methods, such as high-throughput sequencing. This review focuses on four evolutionary primitive true fungal phyla: the Aphelidea, Chytridiomycota, Neocallimastigomycota, and Rosellida (Cryptomycota), most species of which are not polycentric or mycelial (filamentous), rather they tend to be primarily monocentric (unicellular). Zoosporic fungi appear to be both abundant and diverse in many aquatic habitats around the world, with abundance often exceeding other fungal phyla in these habitats, and numerous novel genetic sequences identified. Zoosporic fungi are able to survive extreme conditions, such as high and extremely low pH; however, more work remains to be done. They appear to have important ecological roles as saprobes in decomposition of particulate organic substrates, pollen, plant litter, and dead animals; as parasites of zooplankton and algae; as parasites of vertebrate animals (such as frogs); and as symbionts in the digestive tracts of mammals. Some chytrids cause economically important diseases of plants and animals. They regulate sizes of phytoplankton populations. Further metagenomics surveys of aquatic ecosystems are expected to enlarge our knowledge of the diversity of true zoosporic fungi. Coupled with studies on their functional ecology, we are moving closer to unraveling the role of zoosporic fungi in carbon cycling and the impact of climate change on zoosporic fungal populations.

Development of a pharmacokinetic/pharmacodynamic model for carvedilol to predict beta1-blockade in patients with congestive heart failure.

To determine whether the controlled-release (CR) formulation of carvedilol given once daily provides 24-hour beta1-receptor blockade similar to the currently marketed immediate-release (IR) formulation given twice daily, changes in exercise-induced heart rate after bicycle ergometry were measured. The pharmacokinetic (PK)/pharmacodynamic (PD) relation between S(-)-carvedilol concentration-the enantiomer with beta-blocking activity-and change in exercise-induced heart rate was defined in healthy subjects and was best described using a direct effect inhibitory E(max) model (with E(max) being the maximum effect). The population estimates for E(max) and concentration at 50% of the maximum effect (EC50) were 19.2 beats per minute (an approximately 13% maximum decrease in exercise-induced heart rate) and 7.7 ng/mL, respectively. The PK/PD model was used to predict PD effects in patients with mild-to-severe heart failure and in patients after myocardial infarction with left ventricular dysfunction who had received both the IR and CR formulations of carvedilol. In these patients, carvedilol CR had equivalent predicted overall PD (area under the effect curve) and trough (PD(min)) effects compared with carvedilol IR, indicating 24-hour beta-blocking coverage for the new CR formulation of carvedilol given once daily.

Pharmacokinetic properties of a new controlled-release formulation of carvedilol.

This review summarizes the pharmacokinetics (PK) of carvedilol after administration of a new once-daily controlled-release (CR) formulation. The plasma concentration-time profiles for both R(+)- and S(-)-carvedilol indicate that carvedilol CR will provide coverage over a 24-hour period similar to the current immediate-release (IR) twice-daily formulation. Exposures for both enantiomers, based on area under the curve (AUC), maximum plasma concentrations (C(max)), and trough concentrations, are equivalent for carvedilol CR compared with carvedilol IR. C(max) and AUC of the enantiomers of carvedilol increase in an approximate dose-proportional manner after administration of carvedilol CR over the dose range of 10-80 mg, indicating that the formulation provides consistent PK performance across the dose strengths proposed for marketing. The intrasubject and intersubject variability of carvedilol CR was comparable to carvedilol IR. For carvedilol CR, mean AUC and C(max) were increased <20% after a high-fat meal compared with a standard meal. The CR and IR formulations of carvedilol exhibited equivalent steady-state PK characteristics in the target hypertension and heart failure populations. The availability of once-daily dosing is expected to improve treatment adherence and thereby enhance the effectiveness of carvedilol in routine clinical use.

Pharmacokinetic and pharmacodynamic comparison of controlled-release carvedilol and immediate-release carvedilol at steady state in patients with hypertension.

Carvedilol is indicated for the treatment of essential hypertension and mild-to-severe chronic heart failure, as well as the reduction of cardiovascular mortality in clinically stable post-myocardial infarction patients with left ventricular dysfunction. Carvedilol is a racemic mixture of R(+) and S(-) enantiomers that combines beta(1)-, beta(2)-, and alpha(1)-adrenoceptor blockade. For all indications, the immediate-release (IR) formulation of carvedilol is taken twice daily. A controlled-release (CR) formulation of carvedilol that allows once-daily dosing has recently been developed. In this double-blind, parallel-group, crossover study, 122 patients with essential hypertension were randomly allocated to receive low and high doses of carvedilol or placebo. Patients received either a constant low dose (CR 20 mg once daily or IR 6.25 mg twice daily) or were titrated to a high dose (CR 80 mg once daily or IR 25 mg twice daily) before being crossed over to an equivalent dose of the alternative formulation. The pharmacokinetic (PK) and pharmacodynamic (PD) profiles were compared between patients receiving carvedilol CR and carvedilol IR. The PK profiles for R(+)- and S(-)-carvedilol for the 2 formulations were equivalent (based on area under the curve, maximum plasma concentration [C(max)], and trough drug concentration). Consistent with an extended-release formulation, carvedilol CR delayed C(max) by 3.5 hours compared with carvedilol IR. For both carvedilol CR and IR, the attenuation of exercise-induced heart rate in patients with hypertension was maintained over the entire 24-hour period, and the 2 formulations demonstrated equivalent beta(1)-blocking effects at trough (end of the dosing interval [PD(min)]), suggesting that the rate of absorption does not interfere with the PD effect. In this first direct comparison of carvedilol CR and IR in subjects with hypertension, fewer adverse events were reported while subjects were receiving carvedilol CR (59.1% overall) compared with carvedilol IR (77.5% overall). This was true regardless of dose received. Headache was the most commonly reported adverse event for subjects receiving either formulation of carvedilol and placebo. Importantly, dizziness and headache were reported less often when subjects received carvedilol CR. This is the first study to show that both formulations had comparable beta(1)-adrenergic blockade in patients with essential hypertension under steady-state conditions. Notably, carvedilol CR provides consistent beta(1)-adrenergic blockade over 24 hours with a once-daily dose.