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Biomedical subjects

J Feely

Publications and source records attributed to J Feely.

196 records · Page 11Linked to original sources

A study of the temporal effect of alcohol on human erythrocyte sodium-lithium countertransport in relation to membrane cholesterol and phospholipids.

The effect of a single dose of alcohol (0.8 g/kg), given with "diet coke," on erythrocyte sodium-lithium countertransport (SLC) in relation to membrane cholesterol and phospholipids was assessed over 24 h in 10 healthy volunteers. Baseline passive lithium efflux (0.168 +/- 0.008 mmol l-1 Cell H-1) was increased 1 h (0.202 +/- 0.014 mmol l-1 cell h-1; p < 0.030), and 4 h (0.200 +/- 0.014 mmol l-1 cell h-1; p < 0.020), but similar to that at 24 h postalcohol (0.173 +/- 0.011 mmol l-1 cell h-1). These changes were not associated with any change in intracellular lithium. Control SLC VMAX of 0.387 +/- 0.054 mmol l-1 cell h-1 fell at 1 h (0.328 +/- 0.050 mmol l-1 cell h-1; p = 0.0012) and 4 h (0.312 +/- 0.048 mmol l-1 cell h-1; p < 0.0005). Its value 24 h postalcohol (0.371 +/- 0.047 mmol l-1 cell h-1) was comparable to that at baseline. There was no significant change in the affinity of the transporter for external sodium throughout the experimental period, suggesting that the reduction in VMAX 1 and 4 h after alcohol ingestion resulted from a noncompetitive inhibition. Intracellular sodium 4 h after alcohol was lower than at baseline, but returned to the control value within 24 h. In a control group (n = 5), pretreatment with "diet coke" alone did not alter any of the measured parameters. It is concluded that alcohol pretreatment increases passive lithium efflux and decreases SLC Vmax. Both effects are evident up to at least 4 h postdosing, but recover within 24 h in the absence of further alcohol intake.

Adult↗

Altered plasma protein binding of drugs in thyroid disease.

The plasma protein binding of propranolol and warfarin was studied in vitro by ultrafiltration in hyper- and hypothyroid patients both before and after treatment. The degree of binding of propranolol was significantly decreased in hyperthyroid patients and increased in hypothyroid patients, and was negatively correlated with serum thyroxine and the free thyroxine index. The plasma protein binding of warfarin was also decreased in hyperthyroid patients, but was unchanged in hypothyroid patients. These results suggest that the binding of both acidic and basic drugs may be altered by thyroid disease.

Adolescent↗

Pharmacokinetic drug interactions with propranolol.

Propranolol is widely used in clinical practice and is frequently administered along with other drugs. The co-administration of propranolol and other drugs may result in either propranolol-induced changes in the disposition of other drugs or in effects of the other drugs on the pharmacokinetics of propranolol. These changes may be due to alteration in absorption, metabolism or to haemodynamic effects such as altered liver blood flow. Understanding the pharmacokinetics of propranolol is important to the rational interpretation of the effects of other drugs on propranolol's disposition. The absorption, protein binding and metabolism of propranolol may all be affected by the co-administration of other drugs. Induction of propranolol's metabolism by halofenate, phenytoin, phenobarbitone, rifampicin and alcohol have all been implicated in altering propranolol clearance, while inhibition of hepatic drug metabolising enzymes by chlorpromazine and cimetidine appear to reduce propranolol clearance. Propranolol may also affect the metabolism of other drugs such as antipyrine, chlorpromazine, theophylline and thyroid hormones. Suggestions that propranolol may alter quinidine's elimination have not been substantiated. By reducing liver blood flow propranolol may reduce the systemic clearance of other high extraction drugs such as lignocaine.

Absorption↗

Pharmacoeconomics of lipid lowering therapy in Ireland.

Increases in expenditure on medicines above the level of increases in health care are generally, a feature of all Western health systems. From the early 1990's, the average annual growth rate (AAGR) in pharmaceutical expenditure exceeded the AAGR in health among all the European member states 1. In Ireland, the expenditure on drugs, as a percentage of health care spending, was 7.1% in 1987 compared with 9.2% in 1997. The state expenditure on medicines increased from 165.8 million Pounds in 1993 to 278 million Pounds in 1998 representing an average increase of 11% each year. All the available evidence indicates that the expenditure on medicines will continue to show real growth, and take an increasing share of the total health care budget. Analysis shows that the main reasons driving such growth include those of "product mix"--the prescribing of newer, more expensive medicines, in addition to the 'volume effect' comprising growth in the number of tablets per prescription. These two factors account for 80% of the observed increase in drug cost 2. Six therapeutic classes accounted for 16 of the top 20 most expensive drugs prescribed under the GMS in 1998 3. These areas can be classified as follows: peptic ulcer disease, asthma, hypertension/cardiac failure, antidepressants, anti inflammatory and lipid lowering drugs. In this article we discuss the clinical evidence base, and the pharmacoeconomic implications of lipid lowering therapy in this country.

Clinical Trials as Topic↗

Cholesterol and lipoprotein (a) levels in psoriasis.

Psoriasis is a common condition in the western world, but is uncommon in populations with a low prevalence of atherosclerosis such as Japanese, Blacks and indigenous North Americans. Psoriasis appeared to be more prevalent amongst patients attending our lipid clinic compared to the general population. Lipoprotein (a) (Lp(a)) is elevated in conditions such as coronary heart disease and protein loosing nephropathies. Psoriasis is a condition of increased epidermal protein turnover and loss and thus it might be postulated that increased levels of Lp(a) may be found in patients with psoriasis. The aim of this study was to explore an association between psoriasis and Lp(a) and lipid profiles. No association was found between Lp(a) concentrations and psoriasis. Although six of 36 patients were found to have a cholesterol greater than 7.5 mmol L-1, the mean cholesterol for this group was not elevated.

Adult↗

Poor utilisation and limited impact of formularies on quality of prescribing by hospital doctors.

We determined the utilisation and perceived value of formularies amongst 104 Non Consultant Hospital Doctors (NCHDs). Only 58% routinely carry a formulary, largely the British, National Formulary (BNF) which is considered by 93% to be the best. The overall quality of prescribing in surgical wards was poorer compared to medical wards. However, after distribution of "free BNF's" significant improvements (p < 0.05) occurred, but only in surgical wards and only in aspects of prescribing specifically highlighted (generic prescribing and limiting the duration of intravenous medications). These improvements lasted four weeks before returning to previous levels. Our results suggest that despite recognising their value a significant proportion of Irish hospital doctors do not routinely carry a formulary. The beneficial effects of distributing free formularies was shortlived.

Chi-Square Distribution↗

The impact of hospitalisation on prescribing costs for medical patients returning to the community.

As prescribed drugs represent an increasing expense in the health service, and prescribers assume more responsibility for costs, practitioners both in hospitals and the community are trying to define and limit this cost. We calculated drug costs in 107 consecutive medical admissions through the Accident and Emergency Department of admission and on discharge from hospital. The estimated (mean +/- SD) patient daily cost of drugs rose on admission from Pounds 0.90 +/- Pounds 1.32 to Pounds 2.06 +/- Pounds 2.57 on discharge (p < 0.01) which was partly due to an increased number of drugs on discharge [4.6 +/- 3.0 compared with 2.8 +/- 2.4 on admission (P < 0.01)]. However, the mean daily cost per item per patient also increased significantly from Pounds 0.23 +/- 0.30 to Pounds 0.38 +/- 0.39 during hospitalisation (P < 0.002). This mean daily cost on discharge from hospital was not influenced by patient age or duration of hospital stay. These results confirm that patients on discharge from hospital are prescribed more drugs than on admission but each item on the prescription tends to be more expensive on discharge from hospital.

Anti-Bacterial Agents↗

Knowledge and attitudes to prescribed drugs in young and elderly patients.

Increasing patient knowledge of drug therapy is said to improve compliance and may reduce adverse drug reactions. We assessed patient knowledge of prescribed drugs in fifty patients attending a hypertension clinic [outpatients] and in elderly patients on admission to (n = 129) and on discharge from (n = 100) an acute geriatric assessment unit. We found that 88% of outpatients, 40% of elderly admissions, and 41% of elderly discharges knew the indications for their therapy; only 40% of outpatients, 8% of elderly admissions and 12% of elderly discharges could name their medications. Patients said that their information came principally from the prescribing doctor. In a further study we assessed doctor, nurse, young and elderly patients' ability to discriminate between commonly prescribed white tablets. Errors were made by the doctors on 25% occasions, nurses on 40% occasions and patients on 61% occasions. Young patients made errors 67% of the time and elderly patients 55% of the time. These studies indicate that both inpatients and outpatients, both young and elderly have poor knowledge of their medications. In addition, many commonly prescribed drugs are not easily distinguishable by patient, prescriber or drug administrator. We conclude that there is a need to improve knowledge both in patients and in prescribers. We suggest that prescribers should consider the colour and shape of medications prescribed concurrently as many "little white tablets" are difficult to tell apart.

Adult↗

Low rate of generic prescribing in the Republic of Ireland compared to England and Northern Ireland: prescribers' concerns.

We compared the level of generic prescribing in the Republic of Ireland, Northern Ireland and England and surveyed the views of Irish College of General Practitioners members. In 1993, generic drugs (pure generics and branded generics together) comprised 17.4% of total dispensing in the General Medical Services Scheme, significantly less than Northern Ireland or England where pure generics alone comprised 25% and 38% respectively of total dispensing in the National Health Services. General practitioners accurately self-estimated their level of generic prescribing but are concerned about the reliability/quality of generic products on the market, possible legal liabilities associated with their use and the fact that pharmacists may legally dispense more expensive proprietary preparations in the case of private prescriptions written generically. Prescribers need reassurance regarding legal and quality assurance aspects of generic prescribing if the level of generic drug use is to increase.

Drug Prescriptions↗

Audit of an anticoagulant clinic: doctor and patient knowledge.

Oral anti-coagulation with warfarin is increasingly required in the prophylaxis and treatment of vascular thrombosis and embolism. Unless the degree of anti-coagulation is maintained in the narrow therapeutic range either serious bleeding or failure to prevent thromboembolism may occur. Complications may occur in up to 31% of patients. We randomly sampled 50 patients attending an anticoagulant clinic and interviewed them. We found the PTR between 2.0-4.0 in 70% patients. Their records indicated that they attended 0.9 +/- 0.5 times per month, but the patients themselves said that they had 2.4 +/- 1.7 visits per month, lasting on average 1.9 +/- 0.7 hours per visit. The mean duration of therapy was 4.3 +/- 5.4 years [range 1 month to 26 years]. Many patients perceived that they had received no education about warfarin (23%) while the majority 67% of the remainder said their doctor had educated them. Concomitant aspirin was avoided by 74% patients but 14% considered it safe in combination with warfarin; 49% patients believed that alcohol was safe in combination with warfarin. When asked about the colours and strengths of warfarin tablets, 37% of our sample were completely correct, 9% were completely incorrect and 54% were partly correct. In 16% patients they could not describe their current therapy. As doctors may adjust warfarin dosage for patients in terms of tablet colour, we asked a sample of junior doctors about the colours or strengths of warfarin tablets: 10% were completely correct, one doctor knew none of the colours or strengths and the remainder had a partial knowledge. These studies suggest that the majority of patients on warfarin are cautious about therapy and are safe in their practices. However, we feel that a significant minority may be at risk from complications because of inadequate knowledge. We suggest that improving patient understanding by education may reduce complications and lead to more stable control of anticoagulant therapy.

Anticoagulants↗