A Universal Pharmacological-Based List of Drugs with Anticholinergic Activity

Anticholinergic burden tools have relevant pharmacological gaps that may explain their limited predictive ability for clinical outcomes. The aim of this study was to provide a universal pharmacological-based list of drugs with their documented affinity for muscarinic receptors. A comprehensive literature review was performed to identify the anticholinergic burden tools. Drugs included in these instruments were searched in four pharmacological databases, and the investigation was supplemented with PubMed. The evidence regarding the potential antagonism of the five muscarinic receptors of each drug was assessed. The proportion of drugs included in the tools with an affinity for muscarinic receptors was evaluated. A universal list of drugs with anticholinergic activity was developed based on their documented affinity for the different subtypes of muscarinic receptors and their ability to cross the blood-brain barrier. A total of 23 tools were identified, including 304 different drugs. Only 48.68%, 47.70%, 48.03%, 43.75%, and 42.76% of the drugs had an affinity to the M1, M2, M3, M4, and M5 receptor, respectively, reported in any pharmacological database. The proportion of drugs with confirmed antagonism varied among the tools (36.8% to 100%). A universal pharmacological-based list of 133 drugs is presented. It should be further validated in different clinical settings.

Pharmacist-led medication reconciliation on admission to an acute psychiatric hospital unit

Background

Therapy management in patients suffering from mental health disorders is complex and the risks derived from changes or interruptions of treatment should not be ignored. Medication reconciliation in psychiatry may reduce medication errors and promote patient safety during transitions of care.

Objective

To identify the influence of complementary information sources in the construction of the best possible medication history, and to ascertain the potential clinical impact of discrepancies identified in a medication reconciliation service.

Methods

An observational study was conducted in an acute mental hospital unit, with a further validation in an internal medicine unit. Adult patients taking at least one medicine admitted in the unit were included. Patients/caregivers were interviewed upon admission and the information gathered was compared with hospital medical and shared electronic medical records. Once the best possible medication history was gathered, therapeutic information was reconciled against the prescription on admission to identify discrepancies. Potential clinical impact of medication errors was classified using the International Safety Classification.

Results

During the study period, 148 patients were admitted, 50.7% females, mean age 54.6 years (SD=16.3). Collaboration of a caregiver was a needed in 74% of the interviews. In total, 1,147 drugs were considered to obtain patients' best possible medication history. After reconciliation, 560 clinically sound intentional discrepancies were identified and 359 discrepancies required further clarification from prescribers: 84.12% "drug omission", 5.57% "drug substitution", 6.96% "dose change", and 3.34% "dosage frequency change". Potential clinical impact of these medication discrepancies was classified as: 95 mild, 100 moderate, and 29 severe medication errors.

Conclusion

About 1 in three intentional discrepancies observed in a pharmacists-led medication reconciliation service required further clarification from prescribers, being 80% of them unintentional discrepancies. Results highlight the importance of the caregiver as source of information for the psychiatric patient, the relevance of analyzing shared electronic health records until 6 months before, and the need to use hospital medical records efficiently. Additionally, 29 discrepancies were classified as errors with potentially severe clinical impact. A medication reconciliation service is concluded to be feasible and necessary in a mental health unit.

Feasibility of cardiovascular risk screening in Portuguese community pharmacies

Background:

Cardiovascular disease (CVD) remains the leading cause of human mortality. As highly accessible and qualified health professionals, community pharmacists can be included in the early detection of patients at risk for CVD by implementing CVD screening programs.

Objective:

To assess the feasibility of CVD risk screening services in Portuguese community pharmacies from the evaluation of customers acceptability.

Methods:

A cross-sectional study was conducted in a community pharmacy in Portugal. The purpose of entering the pharmacy was recorded for all customers. Afterwards, the customers were invited to be interviewed by the pharmacist, who registered their willingness to participate and collected the participants’ data and biochemical and physical parameters to assess their CV risk by applying the Systematic COronary Risk Evaluation (SCORE) model. For the participants who were not eligible for the SCORE-based risk assessment, the pharmacist considered the major modifiable CVD risk factors - hypertension, dyslipidemia, smoking habits, obesity, impaired fasting glucose and sedentary behavior - according to the ESC guidelines.

Results:

Picking up medication was the most prevalent reason 69.8% (n=1,600) for entering the pharmacy, and among the contacted customers, 56.4% (n=621) agreed to have their CVD risk assessed. Of the 588 participants, 56.6% (n=333) were already on CV pharmacotherapy and were therefore not eligible for screening. Of the 43.4% (n=255) CV pharmacotherapy-naïve participants, 94.9% (n=242) were screened with at least one CVD risk factor; 52.9% (n=135) were not eligible for the SCORE assessment, of which 92.6% (n=125) presented CVD risk factors. Of the 120 SCORE eligible participants, 80.0% (n=96) were at least at moderate risk of CVD.

Conclusions:

We determined the feasibility of CVD risk screening in Portuguese community pharmacies, as we found high customer acceptability, noted the reasons for nonattendance, and found a high prevalence of CVD risk factors in at-risk patients. This is an opportunity for Portuguese community pharmacists to take a leading role in the early detection of CVD.

Proof-of-Concept Study of Multifunctional Hybrid Nanoparticle System Combined with NIR Laser Irradiation for the Treatment of Melanoma

The global impact of cancer emphasizes the importance of developing innovative, effective and minimally invasive therapies. In the context of superficial cancers, the development of a multifunctional nanoparticle-based system and its in vitro and in vivo safety and efficacy characterization are, herein, proposed as a proof-of-concept. This multifunctional system consists of gold nanoparticles coated with hyaluronic and oleic acids, and functionalized with epidermal growth factor for greater specificity towards cutaneous melanoma cells. This nanoparticle system is activated by a near-infrared laser. The characterization of this nanoparticle system included several phases, with in vitro assays being firstly performed to assess the safety of gold nanoparticles without laser irradiation. Then, hairless immunocompromised mice were selected for a xenograft model upon inoculation of A375 human melanoma cells. Treatment with near-infrared laser irradiation for five minutes combined with in situ administration of the nanoparticles showed a tumor volume reduction of approximately 80% and, in some cases, led to the formation of several necrotic foci, observed histologically. No significant skin erythema at the irradiation zone was verified, nor other harmful effects on the excised organs. In conclusion, these assays suggest that this system is safe and shows promising results for the treatment of superficial melanoma.

Implications of a defined daily dose fixed database for drug utilization research studies: The case of statins in Portugal

AIMS

Given the discrepancies between PDDs (prescribed daily doses) and DDDs (defined daily doses), we aimed to assess the extent of error in the results of an 18-year population-level study on statin utilization in Portugal.

METHODS

The Portuguese regulatory agency provided data for the period 2000-2018 on statin dispensing (C10AA). The DDDs were gathered from the ATC/DDD database. DDDs were calculated by the DDD year-by-year approach (DDD_YEAR ) and by the DDD last-year approach (DDD_LAST ). PDDs were calculated according to the year-by-year approach (PDD_YEAR ). Statin annual utilization rates per 1000 inhabitants per day were also calculated. Percent errors were calculated for PDD_YEAR and DDD_YEAR units.

RESULTS

The DDD_YEAR approach revealed decreases in the consumption of atorvastatin, fluvastatin, lovastatin, pravastatin and simvastatin in 2009, when their DDD was modified. Conversely, the results from both DDD_LAST and PDD_YEAR approaches indicated gradual changes in the actual consumption of all statins in Portugal. Before 2009, atorvastatin, pravastatin and simvastatin utilization was greatly overestimated by DDD_YEAR /1000 inhabitants/day. The average dose of lovastatin prescribed in the past 18 years (20 mg) was below the assigned DDDs during the study period, varying from 30 mg to 45 mg. Conversely, the PDD for fluvastatin was above the DDD values (ranging from 40 mg in 2000 to 70 mg in 2016). For atorvastatin, pravastatin and simvastatin, national PDDs were above the assigned DDD until the DDD modification in 2009.

CONCLUSIONS

A more dynamic system, based on national and annually updated DDDs, should be able to reduce discrepancies between DDDs and PDDs and the bias in utilization studies.

A Step Forward in Breast Cancer Research: From a Natural-Like Experimental Model to a Preliminary Photothermal Approach

Breast cancer is one of the most frequently diagnosed malignancies and common causes of cancer death in women. Recent studies suggest that environmental exposures to certain chemicals, such as 7,12-Dimethylbenzanthracene (DMBA), a chemical present in tobacco, may increase the risk of developing breast cancer later in life. The first-line treatments for breast cancer (surgery, chemotherapy or a combination of both) are generally invasive and frequently associated with severe side effects and high comorbidity. Consequently, novel approaches are strongly required to find more natural-like experimental models that better reflect the tumors' etiology, physiopathology and response to treatments, as well as to find more targeted, efficient and minimally invasive treatments. This study proposes the development and an in deep biological characterization of an experimental model using DMBA-tumor-induction in Sprague-Dawley female rats. Moreover, a photothermal therapy approach using a near-infrared laser coupled with gold nanoparticles was preliminarily assessed. The gold nanoparticles were functionalized with Epidermal Growth Factor, and their physicochemical properties and in vitro effects were characterized. DMBA proved to be a very good and selective inductor of breast cancer, with 100% incidence and inducing an average of 4.7 tumors per animal. Epigenetic analysis showed that tumors classified with worst prognosis were hypomethylated. The tumor-induced rats were then subjected to a preliminary treatment using functionalized gold nanoparticles and its activation by laser (650-900 nm). The treatment outcomes presented very promising alterations in terms of tumor histology, confirming the presence of necrosis in most of the cases. Although this study revealed encouraging results as a breast cancer therapy, it is important to define tumor eligibility and specific efficiency criteria to further assess its application in breast cancer treatment on other species.

Association between anticholinergic burden and anticholinergic adverse outcomes in the elderly: Pharmacological basis of their predictive value for adverse outcomes

The use of anticholinergic drugs and other drugs with anticholinergic activity is highly prevalent in older people. Cumulative anticholinergic effects, known as anticholinergic burden, are associated with important peripheral and central adverse effects and outcomes. Several methods have been developed to quantify anticholinergic burden and to estimate the risk of adverse anticholinergic effects. Serum anticholinergic activity (SAA) and anticholinergic burden scoring systems are the most commonly used methods to predict the occurrence of important negative outcomes. These tools could guide clinicians in making more rational prescriptions to enhance patient safety, especially in older people. However, the literature has reported conflicting results about the predictive ability of these tools. The majority of these instruments ignore relevant pharmacologic aspects such as the doses used, differential muscarinic receptor subtype affinities, and blood-brain barrier permeability. To increase the clinical relevance of these tools, mechanistic and clinical pharmacology should collaborate. This narrative review describes the rational and pharmacological basis of anticholinergic burden tools and provides insight about their predictive value for adverse outcomes.

Size of the associations between anticholinergic burden tool scores and adverse outcomes in older patients

Background Several anticholinergic scales and equations to evaluate the anticholinergic burden have been previously created. Association of these instruments with the anticholinergic outcomes are usually estimated by means of hypothesis contrast tests, which ignore the size of the association effect. Objective To evaluate the effect size of the associations between the scores on cumulative anticholinergic burden instruments with peripheral or central anticholinergic adverse outcomes in older patients. Setting Internal medicine ward of a Tertiary University Hospital. Methods A case-control study was conducted in patients over 65 years who were admitted to two internal medicine wards of a Portuguese university hospital. The Anticholinergic Drug Scale, Anticholinergic Risk Scale, Anticholinergic Cognitive Burden scale and Drug Burden Index were used to calculate the patients' anticholinergic burden. Peripheral (dry mouth-swab technique; dry eye-Schirmer test) and central (falls and cognitive impairment-Mini-Mental State Examination) anticholinergic adverse outcomes were investigated. The Barthel Index was used to assess overall physical functionality. The Mann-Whitney test was used to evaluate probabilistic differences in the anticholinergic scores between case and control individuals. To establish the effect size of the associations, the area under the curve of the receiver operating characteristics curve was calculated. Main outcome measure Anticholinergic adverse effects. Results A total of 250 patients (mean age 81.67 years, standard deviation 7.768; 50% females) were included. In total, 148 patients (59.2%) presented with dry mouth, 85 (34%) with dry eye, 141 (56.4%) with impaired functionality, 44 (17.6%) with a history of falls and 219 (87.6%) with cognitive impairment. Significant differences (p < 0.05) were obtained for the majority of the associations between Anticholinergic Drug Scale, Anticholinergic Risk Scale, Anticholinergic Cognitive Burden and Drug Burden Index and adverse effects. Conversely, the effect sizes of these associations ranged from "fail" (area under the curve 0.5 to 0.6) to "fair" (area under the curve 0.7 to 0.8). Conclusion Although significant differences in the scores of anticholinergic burden instruments and adverse outcomes may exist, the effect sizes of these associations ranged from 'fail' to 'fair', which limits their utility in preventing anticholinergic adverse outcomes with medication review interventions.

Patients' clinical information requirements to apply the STOPP/START criteria

Background The STOPP/START criteria are an explicit tool to detect potentially inappropriate medications (PIMs). Patient clinical information may not be available in all settings. Objective To identify patient clinical information needed to apply the STOPP/START criteria. Setting: Four nursing homes in Portugal. Methods First, a theoretical analysis was performed to identify the patient information required to apply the STOPP/START criteria (v2), according to the following categories: patients' current medication, medication history (previous medication and duration), medical records (current and past medical conditions), and laboratory test results. A verification of the information requirements was conducted through a cross-sectional study on a nursing home population with patients over 65 years old. Patients' medical records were appraised to extract only demographic data and current medication profiles. Main outcome measure Information requirements of STOPP/START. Results For only 29 of the 81 STOPP criteria and 1 of the 34 START criteria, a judgement could be made with only the information in the patient's medication profile. 52 STOPP and 33 START criteria require additional information, (i.e. duration of therapy, previous medication, current and past medical conditions, and laboratory data). The 208 evaluated persons (87 years; 68.75% female) used 1770 medications, with 989 (55.9%) potentially involved in 1629 STOPP criteria. Sufficient information to judge STOPP criteria was available for only 529 (32.5%) potential STOPP criteria situations, with a positive identification of a STOPP PIM in 397 instances (75.0%). Conclusions Although STOPP/START criteria can be considered a high-level tool to identify PIMs, their use may be compromised in scenarios where access to patients' clinical information is limited.

Cross-cultural adaptation and validation of a European Portuguese version of the 8-item Morisky medication adherence scale

INTRODUCTION AND OBJECTIVE

The 8-Item Morisky Medication Adherence Scale (MMAS-8) is one of the most widely used instruments to assess medication adherence, but a validated European Portuguese version of MMAS-8 does not exist. Our aim was to develop and validate a European Portuguese version of the MMAS-8.

METHODS

A process of translation and back-translation of the original MMAS-8 was performed. The questionnaire was administered in nine community pharmacies and one public hospital between March 2014 and September 2015. Adult patients taking at least one antihypertensive drug were invited to participate. A confirmatory factor analysis was performed and internal consistency, convergent validity and concurrent validity were examined.

RESULTS

A total of 472 patients were enrolled in the study. The mean MMAS-8 score obtained was 6.74±1.39. One hundred and thirty-two patients were classified as low adherers (28%), 181 (38.3%) as medium adherers and 159 (33.7%) as high adherers. For the factorial structure of the Portuguese version of the MMAS-8, the fit indices of the final model (chi-square [18] 48.465, p<0.001) are suggestive of very good fit, with comparative fit index 0.95, root mean square error of approximation 0.06 (90% confidence interval 0.04-0.08), and standardized root mean square residual 0.04, confirming that the construct tested was unidimensional. The Cronbach's alpha for all items was 0.60, and the translated version presents convergent validity and concurrent validity.

CONCLUSION

A European Portuguese version of the MMAS-8 was created that maintained a similar structure to the original MMAS-8 and good psychometric properties.

Identification of inhaler technique errors with a routine procedure in Portuguese community pharmacy

Background:

A correct selection of drugs prescribed, but also the choice of the appropriate inhaler device, is crucial for the control of respiratory diseases.

Objective:

To evaluate the inhaler technique and identify potential errors of patients when treated with inhalers by testing a routinary procedure to be implemented in any community pharmacy.

Methods:

Adults with asthma/COPD and under inhalation therapy were invited to demonstrate how they use their inhalers. After direct observation it was registered whether all the sequential steps included in the summary of product characteristics (SmPC) were performed.

Results:

The study involved 67 patients from 4 community pharmacies (Portugal central region): 34 (50.7%) males, 65.4 (SD=18.28) years old, 42 (62.7%) with COPD, and 23 (34.3%) using more than one inhaler. The 67 patients used 95 inhalers, comprising: 57 (60.0%) multiple dose DPI (dry powder inhalers), 18 (18.9%) single dose DPI, 16 (16.8%) pMDI (pressurized metered dose inhalers), 2 (2.1%) pMDI+spacer and 2 (2.1%) SMI (soft mist inhalers). No errors were made only by 9 (13.4%) patients. In the 75 DPIs techniques, the most frequent errors were ‘no previous forced expiration’ (46=61.3%) and ‘no 10s apnea after inhalation’ (51=68.0%); in the 16 pMDIs techniques common errors were ‘lack of hand-lung coordination’ (7=43.8 %), ‘no previous forced exhalation’ (8=50.0%) and ‘no apnea after inhalation’ (10=62.5%). After inhaling from 56 devices containing corticosteroids, 34 (60.7%) of the patients did not wash their mouth.

Conclusion:

The study demonstrated the possibility of performing this procedure routinely in Portuguese community pharmacies and also its utility, since 58 (87%) of patients had at least one error during the inhalers use.

Influence of the mode of administration on the results of medication adherence questionnaires

INTRODUCTION AND OBJECTIVES

Adherence to medication regimen is commonly assessed through questionnaires, some of which are validated via self-administration. The inadequate health literacy of elderly people pushes researchers to the use of interviews as a method of administration. The aims of this study were to compare the results obtained with an interviewer-administered and a self-administered medication adherence questionnaire and to evaluate the consequences of the adherence status classification of individuals.

METHODS

A cross-sectional study was performed in which the Medida de Adesão aos Tratamentos adherence questionnaire was administered to adult patients who were taking at least 1 antihypertensive drug. The data were collected in 7 community pharmacies in central Portugal between March 2014 and September 2015 in 2 different phases: in the first phase, the questionnaire was applied during a healthcare professional interview, and the second phase involved a self-report administration. A confirmatory factor analysis was conducted, and the measurement and structural invariances across the application methods were examined.

RESULTS

A sample of 425 patients with a mean age of 68.21 ± 10.56 years participated in the study. The confirmatory factor analysis revealed that both the interview and self-report had a good fit with the original model, although the self-report results exhibited a better fit. In the interview administration, we obtained lower values for skewness and higher levels of kurtosis. The patients subjected to the interview administration presented with a 9.7% higher tendency to answer "never" when compared with the self-administered application, which overestimated adherence.

CONCLUSIONS

The interview administration method induced bias that led to a higher percentage of "never" answers and a subsequent overestimation of adherence levels. Self-report administration should be preferred in the application of medication adherence questionnaires.

Developing an adherence in hypertension questionnaire short version: MUAH-16

The Maastricht Utrecht Adherence in Hypertension (MUAH) questionnaire provides clinicians with information about the causes of a patient's poor adherence to antihypertensive drugs. In this study, the authors aimed to develop and validate a short version of the MUAH questionnaire. After an exploratory factor analysis, the number of MUAH items was reduced. The original MUAH questionnaire (model 1) was compared with the 16-item MUAH short version (model 2). Next, this short version of MUAH (MUAH-16) with all factors correlated (model 2a) was compared with the short version of MUAH with four subscales that contribute to a global factor of adherence (model 2b). Model 1 had a poor fit to the data (χ² 269 = 663.41, P < .001, comparative fit index = 0.695, root mean square error of approximation = 0.06), and model 2 had a very good fit to the data (χ² 100 = 171.07, P < .001, comparative fit index = 0.92, root mean square error of approximation = 0.04). When comparing model 2a with model 2b, the chi-square difference of the model (Δχ² 2 = 4.06; P = .067) revealed that the fits of both models were not significantly different. These findings suggest that MUAH-16 better represents a patient's adherence to antihypertensive medication than the original MUAH questionnaire.

Advance in methods studying the pharmacokinetics of polyphenols

Significant advances have been achieved during the past decade concerning the metabolism of polyphenol compounds in vitro, but scarce data has been presented about what really happens in vivo. Many studies on polyphenols to date have focused on the bioactivity of one specific molecule in aglycone form, often at supraphysiological doses, whereas foods contain complex, often poorly characterized mixtures with multiple additive or interfering activities. Whereas most studies up to the middle-late 1990s measured total aglycones in plasma and urine, after chemical or enzymatic deconjugation, or both, several recent works now report the polyphenol conjugate composition of plasma, urine, feces and/or tissues, after the administration of pure polyphenols or polyphenol-rich matrices. HPLC methods with electrochemical, mass spectrometric and fluorescence detection have adequate sensitivity. LC/UV-Vis methods have also been widely reported, but they are much less sensitive. Compared with electro-chemical and fluorescence detection, MS can quantify analytes without chromatographic separation, which leads to high throughput, presenting itself as the best choice to date. Regarding the experimental model to monitor the bioavailability of phenolic compounds, most published studies are based on human and animal models, with the majority using rodents, primates and recently the nematode Caenorhabditis elegans. This review focuses on the fundamentals of pharmacokinetic methods from the last 15 years and how the results are evaluated and validated. The types of analytical methods, animal models and biological matrices were used to better elucidate pharmacokinetics of polyphenols.

PERSYVE - Design and validation of a questionnaire about adverse effects of antihypertensive drugs

OBJECTIVE

The aim of this study was to design and validate a questionnaire to measure perceived symptoms associated with antihypertensive drugs (PERSYVE).

METHODS

THE PERSYVE DEVELOPMENT AND VALIDATION INCLUDED FOUR STAGES: 1) item development (bibliographic review and questionnaire elaboration); 2) face and content validation; 3) field testing (pre-test); and 4) test-retest validation, assessment of internal consistency (Cronbach's alpha) and reproducibility over time (intraclass correlation coefficient and Cohen's kappa coefficient).

RESULTS

PERSYVE IS DIVIDED INTO SIX SECTIONS ACCORDING TO RESULTS OBTAINED FROM THE LITERATURE REVIEW: (1) drug adherence, (2) perceived symptoms and how they affect quality of life (five-point Likert scale), (3) communication with health professionals, (4) perception of symptoms as adverse reactions, (5) influence on therapy compliance, and (6) adoption of non-pharmacological methods for blood pressure control. Content and face validation of the questionnaire led to some vocabulary changes and the introduction of section 2.1. Field-testing (n=26) revealed high comprehensibility of the questions. The Cronbach's alpha, calculated for section 2 (five-point Likert scale) was 0.850. PERSYVE was reproducible (n=167): kappa values presented fair to substantial reproducibility and, in section 2, ICC values resulted in good to excellent reproducibility.

CONCLUSION

Results showed that PERSYVE is a well-structured, objective, patient-friendly, valid and reliable questionnaire. PERSYVE can be a very useful instrument in hypertensive patients' monitoring and in the screening of adverse effects.

Correlation between total nitrite/nitrate concentrations and monoamine oxidase (types A and B) and semicarbazide-sensitive amine oxidase enzymatic activities in human mesenteric arteries from non-diabetic and type 2 diabetic patients

The aim of this study was to determine the correlation between total nitrite/nitrate concentrations (NOx) and the kinetic parameters of monoamine oxidase enzymes (MAO-A and MAO-B) and semicarbazide-sensitive amine oxidase (SSAO) in human mesenteric arteries. Arteries were from non-diabetic and type 2 diabetic patients with sigmoid or rectum carcinoma for whom surgery was the first option and who were not exposed to neo-adjuvant therapy. Segments of human inferior mesenteric arteries from non-diabetic (61.1 ± 8.9 years old, 7 males and 5 females, N = 12) and type 2 diabetic patients (65.8 ± 6.2 years old, 8 males and 4 females, N = 12) were used to determine NOx concentrations and the kinetic parameters of MAO-A, MAO-B and SSAO by the Griess reaction and by radiochemical assay, respectively. The NOx concentrations in arteries from diabetic patients did not differ significantly from those of the non-diabetic group (10.28 ± 4.61 vs 10.71 ± 4.32 nmol/mg protein, respectively). In the non-diabetic group, there was a positive correlation between NOx concentrations and MAO-B parameters: K_m (r = 0.612, P = 0.034) and V_max (r = 0.593, P = 0.042), and a negative correlation with the SSAO parameters: K_m (r = -0.625, P = 0.029) and V_max (r = -0.754, P = 0.005). However, in the diabetic group no correlation was found between NOx concentrations and the three kinetic parameters of the enzymes. These results suggest an important function of sympathetic nerves and vascular NOx concentrations in arteries of non-diabetic patients. Thus, these results confirm the importance of a balance between oxidants and antioxidants in the maintenance of vascular homeostasis to prevent oxidative stress.

[Development of a multidimensional system for classification and management of health information: applying to clinical information]

INTRODUCTION

The large amount of information in the medical area creates management problems, being necessary systematic methods for filing and retrieval. With information on the context of clinical records, methods must integrate controlled biomedical terminologies and desirable characteristics oriented to the structure, content and clinical results. The objective is to test the applicability and capacity for retrieval of a multidimensional system developed for classification and management of health information.

METHODS

Three hundred questions were randomly selected, by computerized method, from the questions received in six years (Medicine Information Service, Pharmaceutical Department, Coimbra University Hospitals). They were characterized and applicability evaluated by classified amount and need to alter the system, which is composed of various independent dimensions, incorporating concepts sometimes hierarchical. Questions retrieval was tested searching information in a dimension or between dimensions.

RESULTS

All questions were classified: 53% are clinical cases with illnesses incidence in the genitourinary system; metabolic, nutritional and endocrine disease; cancer; infections and nervous system. In 81%, the object is a drug, mostly anti-infectious and anti-neoplastic agents. The therapeutic and safety areas had been the most requested, regarding the subjects: use, adverse reactions, drug identification and pharmaceutical technology. As to applicability, it was necessary to add some concepts and modify same hierarchical groups, that didn't modify the basic structure, nor had collided with the desirable characteristics. The limitations were related with the incorporated external classification systems. The search in the subject dimension of the concept drug administration retrieved 19 questions. The search between two dimensions: antiinfectious (external) and teratogenicity (subject) retrieved three questions. In the two examples, it was possible to retrieve information from any one of the levels of the hierarchy, from the most general to the most specific and even from external dimensions.

CONCLUSIONS

The use of the system in this sample showed its applicability in clinical information classification and filing, retrieval capacity and flexibility, supporting modifications without interfering with desirable characteristics. This tool allows retrieval of patient-oriented evidence that matters.

Lamotrigine pharmacokinetic/pharmacodynamic modelling in rats

The aim of this study was to perform a pharmacokinetic/pharmacodynamic (PK/PD) modelling of lamotrigine following its acute administration to rats. Adult male Wistar rats were given 10 mg/kg of lamotrigine intraperitoneally. Plasma and brain samples were obtained at predetermined times over 120 h post-dose and analysed by liquid chromatography. The anticonvulsant profile against maximal electroshock seizure stimulation was determined over 48 h after dosing. As a linear relationship between lamotrigine plasma and brain profiles was observed, only the plasma data set was used to establish the PK/PD relationship. To fit the effect-time course of lamotrigine, the PK/PD simultaneous fitting link model was used: the pharmacokinetic parameters and dosing information were used in the one-compartment first-order model to predict concentrations, which were then used to model the pharmacodynamic data with the sigmoid Emax model, in order to estimate all the parameters simultaneously. The following parameters were obtained: Vd = 2.00 L/kg, k(abs) = 8.50 h(-1), k(el) = 0.025 h(-1), k(e0) = 3.75 h(-1), Emax = 100.0% (fixed), EC50 = 3.44 mg/L and gamma = 8.64. From these results, it can be stated that lamotrigine is extensively distributed through the body, its plasma elimination half-life is around 28 h and a lamotrigine plasma concentration of 3.44 mg/L is enough to protect 50% of the animals. When compared with humans, the plasma concentrations achieved with this dose were within the therapeutic concentration range that had been proposed for epileptic patients. With the present PK/PD modelling it was possible to fit simultaneously the time-courses of the plasma levels and the anticonvulsant effect of lamotrigine, providing information not only about the pharmacokinetics of lamotrigine in the rat but also about its anticonvulsant response over time. As this approach can be easily applied to other drugs, it becomes a useful tool for an explanatory comparison between lamotrigine and other antiepileptic drugs.

Neuropharmacokinetic characterization of lamotrigine after its acute administration to rats

The purpose of this study is to characterize the neuropharmacokinetics of lamotrigine following a single intraperitoneal dose. Adult male Wistar rats were given lamotrigine dose of 5, 10, or 20 mg/kg. Blood and brain samples were obtained at predetermined times over 120 h and analyzed by HPLC. The overall characteristics of plasma curves were determined by noncompartmental analysis with WINNONLIN. The kinetic characterization of lamotrigine distribution between plasma and brain was performed by indirect numerical deconvolution with MULTI(FILT). A linear disposition kinetics was observed within 5-20 mg/kg. The lamotrigine concentrations in brain homogenate were approx. twofold higher than in plasma. The following pharmacokinetic parameters were obtained for lamotrigine 5, 10, and 20 mg/kg, respectively: clearance of distribution from plasma to brain normalized with the volume of the brain, CL/V(h(-1)) = 4.64, 2.47, 2.40; brain-to-plasma partition coefficient, P = 0.40, 0.37, 0.34; first-order transfer rate constant from the brain to the plasma, K(h(-1)) = 11.68, 6.68, 5.96; single-pass mean transit time in the brain, MTT(h) = 0.086, 0.150, 0.168. These results indicate that lamotrigine plasma levels may be good indicators of lamotrigine levels in the brain and that higher response intensities could be expected with higher doses of lamotrigine, since efficacious concentrations are maintained for a longer period.

Lamotrigine kidney distribution in male rats following a single intraperitoneal dose

As it has been previously shown that lamotrigine (LTG) accumulates in the kidney of male rats, the purpose of the present investigation was to characterize the kidney profiles of LTG and its kidney distribution pattern in male rats, in order to confirm if a preferential distribution exists and to analyse if it does or does not affect the LTG systemic pharmacokinetics. Adult male Wistar rats were intraperitoneally injected with 5, 10 and 20 mg/kg of LTG. The concentration-time profiles of LTG in plasma and whole kidney were determined over 120 h postdose. The distribution of LTG in the rat kidney was investigated in another group of rats by measuring LTG levels in the renal cortex and medulla. The LTG plasma concentration-time profiles revealed a linear relationship with dose. However, a slight increase in the LTG elimination half-life with dose was observed. In contrast, a nonlinear relationship was established between LTG kidney levels and the dose administered. Consequently, nonparallel patterns were observed between LTG plasma and kidney profiles. The LTG kidney distribution pattern revealed an accumulation of LTG in the renal cortex. The present study demonstrated that LTG distributes preferentially to the kidneys of the male rat in a dose-dependent manner and suggests that such distribution may slightly affect the systemic kinetics of the drug.

Influence of administration vehicles and drug formulations on the pharmacokinetic profile of lamotrigine in rats

Given that administration vehicles and drug formulations can affect drug bioavailability, their influence on the pharmacokinetic profile of lamotrigine (LTG), a new-generation anti-epileptic drug, was studied in rats. Three different formulations administered intraperitoneally at a dose of 10 mg/kg were used: (1) LTG suspended in a 0.25% methylcelulose solution, (2) LTG dissolved in a 50% propylene glycol solution, and (3) LTG isethionate dissolved in distilled water. Plasma and brain homogenate levels were determined in order to evaluate vehicle-dependent drug absorption. The results demonstrated rapid absorption of LTG when it was administered as an aqueous solution, in contrast to a slower and more erratic absorption after the injection of either the lipophilic solution or the suspension. A plasma peak was achieved 15 min post-dose with the aqueous solution, with a brain peak being achieved 15 min later, while with the other formulations both plasma and brain homogenate peaks were reached 2 h after LTG administration. This study suggests that LTG isethionate dissolved in distilled water is the most suitable formulation for successful LTG pharmacokinetic studies in rats.

Prejunctional alpha2A-autoreceptors in the human gastric and ileocolic arteries

This study was undertaken to determine the subtype of prejunctional alpha2-autoreceptors in human blood vessels. Segments of gastric and ileocolic arteries were incubated with [3H]noradrenaline and subsequently perifused with modified Krebs-Henseleit solution containing cocaine (12 microM). Five periods of electrical stimulation (S1-S5) were applied (1 Hz, 1 ms, 50 V for 1 min). Concentration-response curves for the facilitatory effect of eight alpha-adrenoceptor antagonists [rauwolscine, 2-[2-(2-methoxy-1,4-benzodioxanyl)] imidazoline (RX821002), yohimbine, phentolamine, idazoxan, 2-(2',6'-dimethoxyphenoxyethyl)-aminomethyl-1,4-benzodioxan (WB4101), spiroxatrine and prazosin] were determined. All antagonists enhanced the stimulation-evoked overflow of tritium, indicating the existence of alpha2-autoreceptors. The EC30% values of the antagonists (concentrations that increased the evoked overflow of tritium by 30%) were taken as a measure of affinity to the autoreceptors. Correlations between the pEC30% values obtained in the present study and the pKi values of the same antagonists at cloned human alpha2A-, alpha2B-, alpha2C-adrenoceptors expressed in Chinese hamster lung cells and at alpha2D-adrenoceptors in the rat submaxillary gland or the bovine pineal gland showed that the alpha2-autoreceptors in the human gastric and ileocolic arteries resemble most closely the alpha2A-subtype.

Monoamine oxidase activities in human cystic and colonic arteries--influence of age

The deamination of 5-hydroxytryptamine, phenylethylamine and benzylamine by monoamine oxidases (MAO-A and B) and semicarbazide sensitive amine oxidase (SSAO) respectively has been studied in homogenates of human cystic and colonic arteries by radiochemical assays. In cystic artery the deamination is mainly carried out by SSAO with a lower participation of MAO-B. The kinetic parameters were: to MAO-B the Vmax = 15.11 +/- 0.51 nmol/mg protein.h and the Km = 78.51 +/- 5.16 microM (+/- SE) and to SSAO the Vmax = 211.70 +/- 8.75 nmol/mg protein.h and the Km = 211.51 +/- 23.27 microM (+/- SE). We could not measure MAO-A activity in our experimental conditions and also the levels of catecholamines are very low and the histological studies show a poor innervation in these tissues. In colonic artery the kinetic parameters were: to MAO-B the Vmax = 5.09 +/- 0.31 nmol/mg protein.h and the Km = 29.12 +/- 4.55 microM (+/- SE) and to SSAO the Vmax = 273.67 +/- 8.35 nmol/mg protein.h and the Km = 197.89 +/- 21.81 microM (+/- SE). In this artery we could find MAO-A in five among the nine samples studied and the kinetic parameters were: the Vmax = 14.48 +/- 0.82 nmol/mg protein.h and the Km = 136.40 +/- 25.46 microM. As we have performed the experiments with human vessels from donors with different age we could not find any relationship between the activity or affinity, in MAO-B and SSAO, with age. Nevertheless, the results show in cystic artery an increase in the affinity of MAO-B with age when we consider the female group which suggests a possible role of the hormonal condition in this behaviour.

The role of MAO-A and MAO-B in the metabolic degradation of noradrenaline in human arteries

1. Segments of human cystic, gastric and ileocolic arteries were obtained from patients undergoing surgery. 2. Segments of arterial tissues, the noradrenaline content of which ranged between 0.27 and 0.52 microg g(-1), were incubated with 0.1 micromol l(-1) [3H]-noradrenaline for 30 min and the accumulation of the amine as well as the formation of metabolites was measured. 3. In all the arteries, oxidative deamination predominated over O-methylation; the mean values of the deaminated and O-methylated metabolites formed for the three arteries were 247.6 and 82.4 pmol g(-1) tissue, respectively. Dihydroxymandelic acid (DOMA) was the most abundant metabolite. 4. Both clorgyline (a selective MAO-A inhibitor) and selegiline (a selective MAO-B inhibitor) reduced the formation of dihydroxyphenylglycol (DOPEG), DOMA and O-methylated-deaminated metabolites (OMDA), and increased that of normetanephrine (NMN). However, clorgyline depressed the formation of DOPEG more than that of DOMA, while selegiline depressed the formation of DOMA more than that of DOPEG. 5. In conclusion, three major differences distinguish the metabolism of noradrenaline by human arteries from that observed in other species: (1) the large predominance of deamination over O-methylation; (2) the extremely high formation of DOMA; and (3) the relative lack of selectivity of clorgyline and selegiline for MAO-A and B, respectively. Since the arterial vessels used were collected from patients older than 60 years, the morphological changes depending on age may explain the increase in DOMA formation.

Influence of experimental hypercholesterolemia on the monoamine oxidase activity in rabbit arteries

Using a model of experimental atherogenesis in New Zealand rabbits we found a lower noradrenaline level in the aorta than in the femoral artery. The activity of monoamine oxidase was decreased in the femoral artery and increased in the aorta of the cholesterol-fed animals when compared with controls.