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Biomedical subjects

G Tomson

Publications and source records attributed to G Tomson.

At least 55 records · Page 3Linked to original sources
PubMed1992

Randomization by group in studying the effect of drug information in primary care.

Drug information is a technology which is rarely evaluated. Practical and ethical considerations limit the use of a classical experimental method (a randomized controlled trial) in studying the effect of drug information in primary care. An alternative approach, randomization by group, is preferable for several reasons: it avoids contamination of the control group; the effect of information can be evaluated in the natural working environment; and the impact of information is increased via diffusion. This article describes the selection of a control group, the Hawthorne effect and 'blindness' in information experiments. Sample size tables and power calculations are presented when randomization by group is used. The study power is influenced by the number of health centres and the variance between them. The number of doctors per health centre plays a less important role, and the number of patients is relatively unimportant. There is also a need to use qualitative methods to prepare information and to understand factors influencing change of behaviour among prescribers.

Drug Information Services↗
PubMed1992

On the variation in conceptions among primary care physicians regarding hypercholesterolaemia: a phenomenographic analysis.

Twenty primary care physicians at 12 health centres in Sweden were interviewed in a semi-structured way. Analysis was conducted using a phenomenographic method. Concerning the general attitude towards cardiovascular disease (CVD), there were two categories of answers; (A) CVD is a big threat to public health, and the health care system should play an active role in treatment and prevention, and (B) CVD is a symptom of normal aging with little or no need for active health care intervention. Questions on the management of hypercholesterolaemia showed a general acceptance of diet and lifestyle alterations, with a marked reluctance to use drugs except in cases of hereditary hypercholesterolaemia. The physicians were positive to non-commercial information from official sources. Critical opinions existed, however, questioning the adequacy and applicability of the national expert recommendations. There was a general acknowledgement of the importance of patient information, whereas a lack in communication skills was expressed. The description of attitudes and conceptions can assist in the understanding of mechanism underlying physicians' behaviour and provide a base for future information programmes.

Cardiovascular Diseases↗
PubMed1991

Drug use and the role of patients and prescribers.

In order to move towards rational drug use in any national or local setting the methods of inquiry have to be expanded. Both the public and private sector have to be addressed. In the latter the pharmacists might be studied using a tracer, fictitious client. One important factor influencing prescribing, drug information, has rarely been assessed scientifically. Experimental studies using group randomization are, however feasible even in developing countries. The individual human being must be in the focus of drug studies and health care and health in the foreground. The combination of qualitative and quantitative methods will assist us to achieve rational drug use that is culturally acceptable, economically feasible and pharmacologically sound.

Developing Countries↗
PubMed1991

Experimental evaluation of the effects of drug information on antibiotic prescribing: a study in outpatient care in an area of Sri lanka.

The intervention level of epidemiology is useful for studying effects in health systems research. Due to practical and ethical reasons, it is often difficult to apply experimental methods such as classical randomized clinical trials in the field. However with alternative approaches such as 'randomization by group' some of these problems can be overcome. Drug information has since long been considered as an instrument to influence physicians, however evaluation of its effects is a new field of research. In the present study the impact of drug information on prescribing behaviour was evaluated in an outpatient setting in Sri Lanka. The study included 15 state health institutions (45 prescribers) with a common drug formulary. Groups of prescribers were randomized into two interventions; newsletters and newsletters reinforced by a group seminar, and one control group. The target topic was 'rational prescribing of antibiotics'. Some 18,766 randomly selected outpatient drug prescriptions were studied. Antibiotics (and sulphonamides) were prescribed to 33.2% of the patients. An overall trend towards a decrease in proportion of patients prescribed antibiotics in the two intervention groups was seen, although the difference was not significant (p greater than 0.05) compared to the control group. This is similar to the effect of written information on prescribing in other studies. A mean difference of -7.4% in written, -7.3% in written + seminar and -0.4% in the control group was shown. The general antibiotic prescribing pattern did not change in any of the three groups. Penicillin was the most commonly prescribed antibiotic and tetracycline was only rarely prescribed to children. This experiment indicates the feasibility of drug information intervention studies in developing countries.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Bacterial Agents↗
PubMed1991

Drug utilization studies and people. A Swedish perspective.

Innovative ways of collaboration between actors involved are needed to increase the quality of drug therapy. Sweden is fortunate to have access to reliable and detailed statistics on drug sales and prescribing patterns. The various data bases are being described. A common classification system (ATC) and a unit of measurement (DDD) enable comparisons at various levels. Major differences between countries, counties, and health centres are presented. Little is known about the reasons for these differences. In order to leave its infancy, drug utilization studies need that clinical pharmacology establishes linkages with primary health care where a majority of the prescribing takes place. Systems should also be developed activating the prescribers involving them in a revolving cycle of self audit. To study drug use in its context a multidisciplinary approach is needed. The descriptive phase should be complemented by targeted intervention and methods should be developed for drug information. Future drug utilization studies need more of a patient-prescriber perspective (PPP).

Databases, Factual↗
PubMed1990

Paediatric prescribing in out-patient care. An example from Sri Lanka.

Few drug utilization studies have been focused on children in developing countries, where they constitute a large part of the total population. The present study describes prescribing in 5 outpatient departments (15 practitioners) in an area of Sri Lanka over a period of seven months. It includes a random sample of 2484 paediatric consultations. On average, 2.7 drugs were prescribed per patient. With a few exceptions generic prescribing of oral drugs prevailed, and only 1% of the children were given injections. In all, 107 different products were used. Antipyretics, antihistamines, antibiotics and sulphonamides were the most commonly used classes of drugs, being prescribed for 40-50% of the children. Penicillin V represented 43% of the total antibiotic prescribing. Only 1.2% of the children and 0.5% of the infants were given tetracycline. Paracetamol was the preferred antipyretic drug in infants. The use of injectables and tetracycline in children has been reported to be common in other developing countries. The practitioners in Sri Lanka showed a more rational prescribing pattern with the exception of the frequent use of antihistamines, cough medicine and an antiflatulent. The need to develop a paediatric drug policy is discussed.

Age Factors↗
PubMed1990

'Codes' and practice: information in drug advertisements--an example from Sri Lanka.

The amount of scientific information that should appear in an advertisement for a drug has been discussed for over 20 years. The information should promote the rational use of the drug. There is a lack of data from developing countries. We analysed all drug advertisements in the Ceylon Medical Journal (CMJ) 1985-1986. Conformity with the existing WHO guidelines and IFPMA code was also assessed. The 111 advertisements constituted 42% of the pages in the CMJ. Thirty-one of 34 companies were from the industrialized nations. Twenty-one per cent of the advertisements did not have the generic name; 94% had information on indications, whereas only 23 and 22% had information on adverse effects and contraindications. Only 16% provided information on generic name, indications, dosage, adverse effects and contraindications. Despite this 68% satisfied the criteria of the WHO guidelines and IFPMA code mainly under an ill defined 'reminder advertisement' clause. The existing guidelines are insufficient to ensure the minimum scientific information in drug advertisements.

Advertising↗
PubMed1990

Patients, doctors and their drugs. A study at four levels of health care in an area of Sri Lanka.

Few drug utilization studies have been conducted in Sri Lanka and they were register based. We wished to combine records with interviews to study drug use before hospital admission and drug prescribing in wards among 850 randomly chosen inpatients. Four institutions representing different levels of health care were studied. At the end of the study, all 25 practitioners involved were interviewed about how they perceived their prescribing practices. During the 48 h before admission drugs were used by 84% of the patients, of whom 73% took Western and 29% Ayurvedic drugs: combinations were common. The drugs most commonly named were aspirin and paracetamol. The medical records were an unreliable source of information in this respect. Infectious and parasitic disorders, together with respiratory diseases, constituted 40% of the diagnoses. The total number of prescriptions was 3,226. The number of drugs prescribed per patient varied between the institutions, the two extremes being the University (2.7) and the peripheral unit (5.1). Analgesics--antipyretics was the most commonly prescribed class at all institutions, 45.7% and 86%, respectively, of the patients being exposed to these drugs at the two institutions. The prescribing of antibiotics (53%) and antihistamines (65%) was considerably more common in the peripheral unit. The most commonly prescribed single drug products were paracetamol (31.3%), aspirin (20.9%), diazepam (21.8%), chloroquine (14.5%), ampicillin and multivitamins (both 12.6%). Most practitioners indicated deliberate use of active drugs as placebos, one drug chosen being vitamin. They were aware of the need for drug information from sources other than the industry.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Self-prescribing by way of pharmacies in three Asian developing countries.

The pattern of advice given and drugs dispensed at 75 Asian pharmacies in response to the presentation of a fictitious infant with diarrhoea were studied. Only 16 of the 75 pharmacies gave the appropriate advice--oral rehydration or consultation with a health worker. 19 of 25 pharmacies in Bangladesh, 16 of 25 in Sri Lanka, and 24 of 25 in Yemen Arab Republic dispensed drugs, with or without oral rehydration solution. Fixed-dose combinations of antibiotics and antidiarrhoeal drugs were common. The results are discussed in relation to national drug and diarrhoeal control policies. After further development of the method it might become a useful monitoring instrument.

Acute Disease↗
PubMed1982

Maternal kinetics and transplacental passage of pethidine during labour.

1 Pethidine is commonly used in single doses as an analgesic in obstetrics. Plasma concentration-time profiles of pethidine after intramuscular administration of 1.5 mg/kg body weight to 16 pregnant women during labour were investigated. There was only a two-fold variation in peak plasma concentration (300-650 ng/ml). The mean (+/- s.d.) value of the apparent plasma half-life of pethidine was 3.4 (+/- 1.0) h which is not different from that in healthy controls. norpethidine plasma levels were not measurable (less than 10 ng/ml). 2 The placental transfer transfer of pethidine was studied at delivery in samples from the umbilical cord vessels and from a maternal peripheral vein. In another 14 patients serial determinations of pethidine concentration were made in foetal scalp blood and maternal venous blood simultaneously during the different stages of labour. The foeto-maternal drug ratio varied between 0.35 and 1.5 with a positive correlation between ratio and dose delivery time interval. The concentration of pethidine in umbilical cord plasma or blood varied between 60 and 400 ng/ml with dose-delivery time intervals of 30 min to 10.5 h. The foetal concentration of pethidine reached a peak-plateau value between 1-5 h after dose.

Female↗
PubMed1981

Relation of naproxen kinetics to effect on platelet prostaglandin release in men and dysmenorrheic women.

The purpose of our investigation was to determine kinetics of naproxen [(+)-6-methoxy-alpha-methyl-2-naphthaleneacetic acid] relative to its inhibition of PGF 2 alpha release during thrombin-induced platelet aggregation in man after a single oral dose of 250 or 500 mg. Naproxen and its metabolite 6-hydroxy-alpha-methyl-2-naphthaleneacetic acid were measured by high-performance, reversed-phase liquid chromatography with fluorimetric detection. PGF 2 alpha was measured by radioimmunoassay in platelet-rich plasma (PRP). Our subjects were four healthy adult men and five dysmenorrheic women. Peak concentrations of naproxen varied between 26 and 69 microgram/ml and half-lifes varied between 9.5 and 21.9 hr, mean = 16.4 hr +/- 4.4 (SD). Naproxen plasma protein binding exceeded 99.9%. The concentration of the metabolite was less than 1% of naproxen and followed the same plasma concentration profile as the parent compound. The based concentration of PGF 2 alpha varied between 0.13 and 6.3 ng/ml, mean = 1.5 +/- 1.9 ng/ml. With no exception, there was a marked decrease in the PGF 2 alpha concentration in thrombin-stimulated PRP during therapy, and concentration was inversely correlated to the total plasma naproxen concentration.

Adult↗
PubMed1981

Phenytoin and IgA concentrations in plasma and saliva in epileptic children.

The concentrations of immunoglobulin A (IgA) and phenytoin were determined in 36 epileptic children with a mean age of 11 years. There was a good correlation between the plasma and saliva concentrations of phenytoin (r = 0.94). The concentration of phenytoin and IgA showed little variation during the dosage interval. The phenytoin treated children did not differ with respect to the concentrations of IgA in saliva in comparison to the controls.

Adolescent↗
PubMed1980

Prenatal and neonatal drug metabolism in man.

Drug oxidations are catalyzed by the liver microsomal fraction of human fetuses but not by fetal livers from most experimental animals. In contrast, glucuronidation of some substrates is catalyzed by the rat fetal liver in late gestation but not in the human fetal liver. The deficient human fetal glucuronidation seems to be compensated for by early development of sulfation activity. The inconsistency of the results from animal fetuses and human fetuses shows that animal data have little relevance for the human fetus. No generalized statements can be made about drug disposition in the newborn infant as compared to adults. Although most drugs that are oxidized have prolonged plasma half-lives in the neonatal period there are examples of drugs with half-lives similar to, or even shorter than, the average half-lives in adults. Oxazepam is conjugated with glucuronic acid in adults. The neonatal plasma half-life of this drug is considerably prolonged. This is true also for its conjugate as would be expected from the immature renal function in newborns. Adequate pharmacokinetic information is a prerequisite for rational and safe drug treatment in the neonatal period.

Adult↗
PubMed1978

High incidence of a concentration-dependent skin reaction in children treated with phenytoin.

A particularly high incidence of rash was seen in children with epilepsy treated with phenytoin. Ten children with untreated epilepsy were therefore included in a prospective study and given either 3 (group 1) or 6 (group 2) mg of phenytoin/kg body weight/day for five days followed by 6 mg/kg body weight/day for both groups. Four of the five children in group 2 compared with only one of the five in group 1 developed a rash seven to 12 days after the start of treatment. Patients with rashes had significantly higher plasma phenytoin concentrations. Whenever the phenytoin concentration was higher than 14 micromol/l on day 5 a rash occurred. These findings indicate that the generalised skin reaction is caused by a high body burden of phenytoin, which results from either a high load of the drug or a low clearance rate.

Adolescent↗