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Biomedical subjects

J Hirsch

Publications and source records attributed to J Hirsch.

At least 361 records · Page 20Linked to original sources
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Nutritionally-induced changes in parasympathetic function.

It is possible to quantify the input of the parasympathetic nervous system to heart rate variability in man by the spectral analysis of heart rate variability. This is done by noninvasive, computerized electrocardiography over several minutes of observation. Earlier studies from this laboratory demonstrated that when body weight of obese or nonobese subjects is increased 10% or decreased below usual body weight, there are accompanying changes in autonomic function, as measured by alterations in heart rate variability. The clearest of these changes is an abrupt decline in parasympathetic function with increase in body weight, and an increase in parasympathetic activity as body weight declines, and when new, lower body weights are maintained. Recently, it has been possible to examine this phenomenon by a pharmacologic dissection of the autonomic input to heart rate variability. The separate input of each branch of the nervous system to cardiac variability, as well as the intrinsic heart rate, is measured by this approach. The subjects studied to date have been few, but there is confirmation of a major change in parasympathetic function with weight alteration whereas sympathetic changes are small.

Body Weight↗
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Ondansetron: a cost-effective advance in anti-emetic therapy.

A cost-effectiveness analysis is one form of full economic evaluation where drug acquisition costs and the costs that are incurred as a result of using a particular treatment are assessed together with clinical efficacy. This paper reviews two such studies. One of the studies was a prospective randomised cost-effectiveness study which compared ondansetron (8 mg i.v. 0, 4 and 8 h following chemotherapy) with metoclopramide (3 mg/kg i.v. followed by an infusion of 0.5 mg/kg/h for 8 h) over the first 24 h following chemotherapy in hospitalised patients receiving highly emetogenic chemotherapy. This study showed that the cost per successfully treated patient (defined in this study as having < or = 1 emetic episode and no adverse events) for these 2 treatments were approximately equal: ondansetron pounds 95 and metoclopramide pounds 92. The second study was an economic evaluation based on data collected over a 5-day period following cyclophosphamide-based chemotherapy given on an outpatient basis for the treatment of breast cancer. Patients received an intravenous dose of 16 mg dexamethasone with either 8 mg ondansetron or 60 mg metoclopramide intravenously before chemotherapy followed by oral dosing with 8 mg ondansetron or 20 mg metoclopramide 3 times daily for 5 days. The costs per successfully treated patient (defined in this study as no vomiting or retching episodes and no anti-emetic-related adverse events during the 5-day period) were comparable: ondansetron pounds 184 and metoclopramide pounds 160. A recent study has established that ondansetron (8 mg) given orally twice daily is as effective as the same dose given 3 times a day. A sensitivity analysis using the cost of an ondansetron twice daily regimen showed that ondansetron is more cost-effective than metoclopramide (pounds 133 vs. pounds 160). These cost effectiveness studies have shown that ondansetron is at least as cost-effective as metoclopramide and simplified ondansetron dosing schedules render ondansetron more cost-effective. These full economic evaluations illustrate that drug acquisition costs can be a misleading guide to the economic impact of antiemetics.

Breast Neoplasms↗
PubMedDate not supplied

Histamine receptor antagonists and lipid stability in total nutrient admixtures.

Drug stability and compatibility studies should be performed for all medications added to total nutrient admixtures (TNAs) before administration to patients. The stability of TNA components will vary depending on product selection and final concentrations. This variability prohibits generalizing published study results generically to TNAs containing untested products or combinations. Histamine receptor antagonists (H2RAs) are commonly administered by continuous infusion via nutrient solutions. When the delivery vehicle is a TNA, comparative stability and compatibility studies performed under similar test conditions are lacking. The stability of marketed parenteral H2RAs and of the investigational H2RA, nizatidine was analyzed in TNA solutions containing either Liposyn II or Intralipid at differing concentrations. All H2RAs remained at more than 90% of initial concentration at 24 hours. After 48 hours, only ranitidine concentrations fell to less than 90% in all study solutions. Each TNA containing an H2RA was within pH stability ranges for lipid products, and no change in particle size was detected during the 48-hour period. This is the first report determining H2RA compatibility and stability in TNA solutions with both 3% and 5% Intralipid and Liposyn II and using similar methodology for all standard H2RA concentrations. Results suggest that these drugs are stable for 24 hours in TNAs containing either lipid product. Beyond this time, administration of ranitidine may be unreliable because of poor stability under the conditions tested.

Drug Stability↗