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J J de Gier

Publications and source records attributed to J J de Gier.

18 recordsLinked to original sources
PubMed2006

Comparison of urine and oral fluid as matrices for screening of thirty-three benzodiazepines and benzodiazepine-like substances using immunoassay and LC-MS(-MS).

Benzodiazepines are the most frequently detected medicinal drugs in drivers. The use of benzodiazepines is associated with an increased road accident risk. In this study, the presence of benzodiazepines detected by liquid chromatography-(tandem) mass spectrometry [LC-MS(-MS)] in oral fluid and urine samples obtained from drivers stopped during a roadside survey was compared. In addition, the sensitivity and selectivity of enzyme multiplied immunoassay technique (EMIT II Plus) relative to LC-MS(-MS) was determined for both matrices. A total number of 1,011 urine samples were collected and screened for benzodiazepines using immunoassay (IA) (EMIT II Plus; cutoff 300 ng/mL). In the IA-positive (n = 25) and a group of randomly selected negative urine samples (n = 79), the presence or absence of benzodiazepines was confirmed by LC-MS-MS after deglucuronidation. The corresponding oral fluid samples (n = 101, 3 samples omitted), were analyzed by LC-MS(-MS) and IA (EMIT II Plus; cutoff 10 ng/mL). The presence of benzodiazepines was demonstrated by LC-MS-(MS) in all IA-positive urine samples, but in only four corresponding oral fluid samples. Concentrations in oral fluid were, one substance excepted, lower than in urine. The sensitivity and specificity of EMIT II Plus were better by using urine as matrix for screening of benzodiazepines than by using oral fluid. The results show that benzodiazepines are detectable in oral fluid. More research has to be done to determine the pharmacokinetic profile of the different benzodiazepines in oral fluid and to study the relationship between dose, concentration (in oral fluid and blood), and impairment.

Benzodiazepines↗
PubMed2005

Drug use and the severity of a traffic accident.

Several studies have showed that driving under the influence of alcohol and/or certain illicit or medicinal drugs increases the risk of a (severe) crash. Data with respect to the question whether this also leads to a more severe accident are sparse. This study examines the relationship between the use of alcohol, illicit drugs and/or medicinal drugs and the severity of an accident within a group of drivers that were involved in a crash in The Netherlands. Blood samples of 993 drivers, collected in the period from October 1998 through September 1999, were linked to accident characteristics as available from the National Transport Research Centre. The outcome measure was the severity of the accident. An accident was considered severe when the accident had resulted in hospital admission or death. All the blood samples obtained after the accident were screened for the presence of alcohol, illicit drugs (opiates, amphetamines and amphetamine-like substances, cocaine and metabolites, methadone, cannabinoids) and medicinal drugs (benzodiazepines, barbiturates and tricyclic antidepressants). The strength of the associations between exposure to the different classes of alcohol/drugs/medicines and the severity of the accident was evaluated using logistic regression analysis and were expressed as odds ratios (OR), adjusted for age, gender, time of the day, day of the week and urban area. The most frequently detected drugs were cannabinoids, benzodiazepines and cocaine. Our results showed no clear association between the use of alcohol, illicit drug and/or medicinal drug use and the severity of the accident. Given the process of obtaining blood samples from drivers involved in accidents and the retrospective nature of the study, we cannot rule out the occurrence of selection bias. Therefore, our findings need further confirmation.

Accidents, Traffic↗
PubMed2004

Quantitative analysis of 33 benzodiazepines, metabolites and benzodiazepine-like substances in whole blood by liquid chromatography-(tandem) mass spectrometry.

A quantitative method using high-performance liquid chromatography-mass spectrometry (LC-MS, ion trap) after matrix supported liquid-liquid extraction is described for the simultaneous determination in whole blood of 33 benzodiazepines including metabolites and benzodiazepine-like substances. The limits of detection (LOD) range from 0.0001 to 0.0126 mg/l. Linearity is satisfactory for all compounds. The extraction recoveries for the benzodiazepines in whole blood are between 60 and 91%, desmethyldiazepam, OH-bromazepam and brotizolam excepted. Selectivity, accuracy and precision are satisfactory for clinical and forensic purposes.

Benzodiazepines↗
PubMed2004

Psychoactive substance use and the risk of motor vehicle accidents.

The driving performance is easily impaired as a consequence of the use of alcohol and/or licit and illicit drugs. However, the role of drugs other than alcohol in motor vehicle accidents has not been well established. The objective of this study was to estimate the association between psychoactive drug use and motor vehicle accidents requiring hospitalisation. A prospective observational case-control study was conducted in the Tilburg region of The Netherlands from May 2000 to August 2001. Cases were car or van drivers involved in road crashes needing hospitalisation. Demographic and trauma related data was collected from hospital and ambulance records. Urine and/or blood samples were collected on admission. Controls were drivers recruited at random while driving on public roads. Sampling was conducted by researchers, in close collaboration with the Tilburg police, covering different days of the week and times of the day. Respondents were interviewed and asked for a urine sample. If no urine sample could be collected, a blood sample was requested. All blood and urine samples were tested for alcohol and a number of licit and illicit drugs. The main outcome measures were odds ratios (OR) for injury crash associated with single or multiple use of several drugs by drivers. The risk for road trauma was increased for single use of benzodiazepines (adjusted OR 5.1 (95% Cl: 1.8-14.0)) and alcohol (blood alcohol concentrations of 0.50-0.79 g/l, adjusted OR 5.5 (95% Cl: 1.3-23.2) and >or=0.8 g/l, adjusted OR 15.5 (95% Cl: 7.1-33.9)). High relative risks were estimated for drivers using combinations of drugs (adjusted OR 6.1 (95% Cl: 2.6-14.1)) and those using a combination of drugs and alcohol (OR 112.2 (95% Cl: 14.1-892)). Increased risks, although not statistically significantly, were assessed for drivers using amphetamines, cocaine, or opiates. No increased risk for road trauma was found for drivers exposed to cannabis. The study concludes that drug use, especially alcohol, benzodiazepines and multiple drug use and drug-alcohol combinations, among vehicle drivers increases the risk for a road trauma accident requiring hospitalisation.

Accidents, Traffic↗
PubMed2000

Clinical pharmacy in primary care and community pharmacy.

The role of the community pharmacist involved in primary care has been undergoing change. In the late 1970s and early 1980s, developments in computerized medication surveillance within the Netherlands enabled pharmacists to react to prescriptions and detect inappropriate pharmacotherapy in community pharmacy sites. This activity became more clinically or patient-oriented in the late 1980s. In the early 1990s, pharmaceutical care was introduced in community pharmacy practice, and emphasis was given to providing patient-centered care and documenting cognitive services. The key features of pharmaceutical care provided in the primary care setting are described based on a review of the literature and on experiences in the Netherlands. Patient outcomes have yet to be shown to be improved by community pharmacy practice; methods for measuring performance are still lacking. Methods to evaluate the extent of integration of community pharmacy services into the clinical team are also lacking but are needed in order to define the future role of community pharmacists in the primary care setting. Integrated care needs to be developed in the Netherlands in order to present the next phase in the process of the "pharmaceutical evolution."

Community Pharmacy Services↗
PubMed1998

Prescription patterns of diuretics in Dutch community-dwelling elderly patients.

AIMS: To describe age- and gender-related prescription patterns of diuretics in community-dwelling elderly, and to compare diuretics to other cardiovascular (CV) medications. METHODS: Cross-sectional study of patient-specific prescription data derived from a panel of 10 Dutch community pharmacies. Determination of proportional prescription rates and prescribed daily dose (PDD) of diuretics, cardiac glycosides, nitrates, angiotensin converting enzyme (ACE) inhibitors, beta-adrenoceptor blockers, and calcium channel blockers in all 5326 patients aged 65 years or older dispensed CV medications between August 1st, 1995 and February 1st, 1996. RESULTS: Diuretics were prescribed to 2677 of 5326 patients (50.3%), 1325 patients (24.9%) using thiazides and 1198 patients (22.5%) using loop diuretics. Prescription rates of loop diuretics increased from 15.1% in patients aged 65-74 years to 37.2% in patients aged 85 years or older. Rates also increased for digoxin and nitrates. Rates for thiazide diuretics remained unchanged with age; rates for beta-adrenoceptor blockers, ACE inhibitors and calcium channel blockers declined with age. Thiazides were prescribed to 30.1% of women compared with 16% of men (P < 0.001). Average PDD was 135 +/- 117% of defined daily dose (DDD) for loop diuretics, and highest for bumetanide (245 +/- 2.01% of DDD, equivalent to 2.5 +/- 2.0 mg). Average PDD was 74 +/- 40% of DDD for thiazides, and highest for chlorthalidone (100 +/- 49% of DDD, equivalent to 25 +/- 12 mg). CONCLUSIONS: Important characteristics of diuretic usage patterns in this elderly population were a steep increase in loop diuretic use in the oldest old, a large gender difference for thiazide use, and high prescribed doses for thiazides.

Age Factors↗
PubMed1996

The Electronic Pharmaceutical Dossier: an effective aid to documenting pharmaceutical care data.

Pharmaceutical care involves decision-making based upon communication and judgements to avoid, initiate maintain or discontinue pharmacotherapy. After establishing patient-pharmacist relationships and implementing collaboration with physicians based upon consensus guidelines, relevant information should be collected and processed in order to determine drug therapy problems and desired treatment outcomes. This paper describes in short the development of a 'care concept' for pharmaceutical care and focuses in particular on the fully integrated functions of a pharmacy automation system (Pharmacom) for documenting relevant data and supporting the processing of drug therapy.

Communication↗
PubMed1988

The stability of benzodiazepines in saliva.

The stability of some selected benzodiazepines in saliva has been studied. The benzodiazepines nitrazepam and clonazepam were found to be unstable in saliva at room temperature and nitrazepam was converted into 7-aminonitrazepam. The conversion rate of nitrazepam was strongly dependent on the composition of the subject's saliva. Nitro-reduction may complicate the use of saliva in epidemiological studies on drugs and driving. This could occur particularly if saliva drug concentrations are to be used as a quantitative measure of driving performance.

Benzodiazepines↗
PubMed1987

Complications in correlation studies between serum, free serum and saliva concentrations of nitrazepam.

The relation between free serum and saliva concentrations of nitrazepam in healthy male volunteers has been studied. It was found that the average value of free serum concentrations from all volunteers was twice the average value of corresponding saliva concentrations. Sometimes mean values of serum, free serum and saliva concentrations are used in correlation studies. However, the data from individual volunteers showed that there was no correlation between them. Statistics can easily introduce false pictures for correlations between free serum and saliva concentrations of nitrazepam, whereas no correlation could be found on the basis of results from individuals. In response studies such as the effects of drugs on driving performance, the free serum and saliva concentrations of a drug from individual volunteers should therefore be considered. This will complicate the use of saliva in epidemiological studies on drugs and driving.

Adult↗
PubMed1986

Evidence for distinct consecutive steps in the neutral to base transition of human serum albumin.

The neutral to base transition in human serum albumin has been studied by means of circular dichroism and equilibrium dialysis using nitrazepam as the non-covalently bound circular dichroic probe. Spectroscopically two transitions were observed over the pH range 5.5-8.5, whereas dialysis data point to only one transition occurring in the latter part of the pH region studied. Both pH dependences could only be correlated if it is assumed that the neutral to base transition consists of at least two distinct consecutive steps.

Binding Sites↗
PubMed1986

Diazepam-induced changes in signal detection performance. A comparison with the effects on the Critical Flicker-Fusion Frequency and the Digit Symbol Substitution Test.

The effects of 10 mg diazepam on signal detection theory measures (stimulus sensitivity, response bias) and reaction times were studied in a 1-hour visual signal detection task with high and low signal probability, and on performance in two short-duration tasks: Critical Flicker-Fusion Frequency (CFF) and the Digit Symbol Substitution Test (DSST). 12 healthy volunteers participated in this placebo-controlled, double-blind cross-over study. Diazepam affected the stimulus sensitivity and the reaction times of hits in the signal detection task. DSST performance was also impaired while CFF did not change after diazepam treatment. No relationship between serum diazepam concentration and change in task performance was found. It is concluded that diazepam affects signal detection performance, independent of signal probability. A short-duration task like the DSST is as sensitive to the effects of diazepam as the (long-duration) signal detection task.

Adolescent↗
PubMed1985

Alcohol effects on signal detection performance.

The acute effects of alcohol (0.7 g/kg) on visual signal detection performance and critical flicker fusion frequency (CFF) of normal volunteers were investigated using a signal detection theory analysis. When signal probability was low, alcohol affected the stimulus sensitivity and the reaction times of hits. Under a high signal probability these indices were not affected, whereas the response bias did not change after the administration of alcohol under both signal probabilities. CFF values were not altered by alcohol. A correlation was found between the magnitude of the alcohol effect and the performance level under placebo. Changing the signal probability caused significant differences between the sensitivity measures, the response bias measures and the reaction times of hits. It is concluded that alcohol affects signal detection performance under conditions of low signal probability. Individuals with a relatively low performance level are more susceptible to the effects of alcohol.

Adult↗
PubMed1984

Driving tests with patients.

Mental illness and the use of psychotropic drugs are considered to influence driving skills of patients. However, studies which indicate the relative contributions of these factors are rare. It is emphasized that for measuring the effects of psychotropic drugs on driving performance of patients, real driving tests are needed. Actual driving and psychomotor performance of patients receiving diazepam, and patients and healthy volunteers receiving mebhydrolin were measured to illustrate the use of real driving tests. The results of both studies are discussed in terms of problems associated with the application of these tests. Patient recruitment is considered to be a major problem. To draw conclusions under these circumstances is extremely difficult, but still acceptable in comparison with the limitations and methodological difficulties of the more commonly used laboratory tests. Some guidelines for driving tests with patients are given.

Adult↗
PubMed1983

The role of buffer composition during equilibrium dialysis in determining concentrations of free diazepam in serum.

Serum levels of free diazepam as determined with equilibrium dialysis depend on the composition of the dialyzing buffer with respect to Ca2+ and Cl-. Physiological concentrations of these ions double the obtained free serum levels, in line with data of diazepam containing albumin solutions. The diazepam binding capacity of serum was found to be higher than that of albumin alone, suggesting that albumin is probably not the only diazepam binding protein in serum. Evidence was also found that the diazepam binding to these other serum proteins is dependent on the presence of Ca2+ and Cl-.

Buffers↗
PubMed1981

Psychomotor performance and real driving performance of outpatients receiving diazepam.

The primary aim of this study was to compare task performance in a laboratory test and real driving performance of outpatients receiving diazepam medication with those of control subjects. Plasma and saliva samples were taken to investigate a level-response relationship. Real driving performance was measured by trained observers. The design of the laboratory test was based on a vigilance task (high attention) directly followed by a simple eye-hand coordination tasks (low attention). Twenty-two males participated in the study. Diazepam was given orally by prescription, mostly as a maintenance dose of 5 mg three times a day. Patients receiving diazepam showed impaired performance in the driving test and the low-attention task. Furthermore, the results indicate no relationship between plasma or saliva levels of diazepam and/or its metabolite N-desmethyldiazepam and real driving performance and/or laboratory task performance.

Adult↗
PubMed1980

Comparison of plasma and saliva levels of diazepam.

1. Salivary, unbound and total plasma levels of diazepam have been compared in nineteen subjects. 2. Salivary diazepam levels were significantly higher (P < 0.001) than, but closely related to the corresponding unbound levels (r = 0.97) at 2.5-3 h after administration of the drug. 3. The results presented suggest that saliva levels can be used to predict the corresponding plasma levels at a given time, but there is no 1:1 relation between the unbound diazepam concentration in plasma and the saliva level of the drug.

Adult↗
PubMedDate not supplied

Medication assistance: the development of drug surveillance and drug information in The Netherlands.

OBJECTIVE: To describe the development of drug surveillance and drug information in The Netherlands. DATA SYNTHESIS: Historically, the professions of medicine and pharmacy have existed separately with little contact between them. Since the 1960s, this situation has changed in The Netherlands. Both professions are cooperating to an ever-increasing degree, primarily in the areas of computerized drug surveillance and individualized patient drug information, resulting in greater patient benefit. CONCLUSIONS: Exchange of knowledge between physicians and pharmacists, greater cooperation among professionals, use of computerized patient medical records, and involvement of the patient in his own healthcare will have a positive influence on the development of drug assistance in the future.

Clinical Pharmacy Information Systems↗