Biomedical subjects

M V Calvo

Publications and source records attributed to M V Calvo.

9 recordsLinked to original sources

PubMed1992

Decision analysis to assess cost-effectiveness of low-osmolality contrast medium for intravenous urography.

Decision analysis was used to compare the cost-effectiveness of a conventional ionic high-osmolality contrast medium with that of a nonionic low-osmolality contrast medium when used for i.v. urography. The patient populations considered in the model were those with a low risk and those with a high risk of contrast medium-associated adverse effects. Mean toxicity rates for the contrast media were obtained from the literature. To estimate the average cost of adverse effects, the probability of a patient in each population developing a mild, moderate, or severe reaction was multiplied by the respective estimated cost for each level of severity, and the products were summed. The incremental cost of the low-osmolality medium per case of adverse effects prevented was calculated by dividing the difference between the average costs of the two media by the difference between the frequencies of toxicity associated with the agents. According to the 1990 cost data used, combined mean drug and toxicity costs were $68 and $13 for the low- and high-osmolality contrast media, respectively, per high-risk patient and $67 and $10 per low-risk patient. The incremental costs of the low-osmolality medium per case of severe adverse effects prevented was $17,974 in the high-risk population and $77,027 in the low-risk population. Sensitivity analysis showed the results to be stable over a range of data used in the model.(ABSTRACT TRUNCATED AT 250 WORDS)

Contrast Media↗

PubMed1990

Analytical evaluation of TDx cyclosporine and metabolites fluorescence polarization immunoassay and comparison with the Cyclo-Trac RIA kit.

The fluorescence polarization immunoassay (FPIA) developed by Abbott Laboratories (TDx system) for the determination of cyclosporine in plasma was evaluated using whole blood as the analytical sample. The coefficients of variation for the within-run and between-run precision ranged from 3.7 to 5.7% and from 5.5 to 7.3%, respectively, for cyclosporine controls ranging in concentration from 200 to 1500 ng/ml. The detection limit was seen to be 26 ng/ml. We used specimens from renal transplant patients who received cyclosporine to compare the TDx assay with the RIA method (Incstar Cyclo-Trac). There was a good correlation between FPIA and RA results (r = 0.91; TDx = 1.29 RIA + 39.13; n = 88). It was concluded that the FPIA is an acceptable and rapid method for patient cyclosporine analysis in whole blood samples. In therapeutic drug monitoring this method offers advantages over the RIA procedure.

Cyclosporins↗

PubMed1990

Decision analysis applied to selection of histamine H2-receptor antagonists for the formulary.

The use of decision analysis in selecting a histamine H2-receptor antagonist for the formulary at a hospital in Spain is described. Cimetidine, ranitidine, and famotidine were identified as the possible alternatives. The evaluation criteria established were therapeutic efficacy, adverse effects, drug interactions, years of clinical use, dosage interval, cost, and dosage forms. The relative importance of the criteria was determined by assigning utility values to each. Probability values were assigned to estimate how well each drug met each criterion. By multiplying the utility and probability values for each criterion and summing the scores, a total score was calculated for each drug. The alternative with the highest total score was ranitidine. A sensitivity analysis showed that the results were stable over a plausible range of probability and utility values. Accordingly, ranitidine was selected for inclusion on the formulary. Decision analysis provided an effective method for selecting which histamine H2-receptor antagonist to include on the hospital's formulary.

Decision Making, Organizational↗

PubMed1990

[Decision analysis in antibiotic therapy].

Decision analysis constitutes a systematic approach for taking decisions in situations of uncertainty. This technique allows one to evaluate all therapeutic options and to quantify the possible results, with a view to selecting therapeutic regimens that have the best cost-effectivity relationship. Cost-benefict and cost-effectiveness studies have become increasingly more interesting in the evaluation of antibiotic therapy. In the present paper a review is offered of all factors that, both in antibiotic prophylaxis and the treatment of established infections, govern the cost-effectivity relationship of one's decisions. A review is also made of the methodology of decision analysis, whose use in antiinfective therapy seems sufficiently clear, specially as an objective criterion in the choice of antibiotics.

Anti-Bacterial Agents↗

PubMed1989

Interaction between digoxin and propafenone.

The pharmacokinetic and pharmacodynamic interactions between digoxin and propafenone were investigated in 10 hospitalized patients with heart disease and cardiac arrhythmias. During steady state (0.25 mg/day) the glycoside was combined with 600 mg of propafenone daily for 1 week. The mean +/- SD serum digoxin concentration (SDC) was 0.97 +/- 0.29 ng/ml before and 1.54 +/- 0.65 ng/ml (p less than 0.003) during propafenone administration. Propafenone induced a mean decrease in 31.1 and 31.7% in total and renal digoxin clearances, respectively. The increase in SDCs was accompanied by a decrease in heart rate (HR) and shortening of QTC (QT interval corrected for HR). In patients receiving digoxin and propafenone simultaneously, the SDCs should be monitored and the digoxin dose reduced if there is evidence of toxicity.

Adult↗

PubMed1989

Population pharmacokinetic study of gentamicin and a Bayesian approach in patients with renal impairment.

A population pharmacokinetic study was conducted on a total of 70 patients receiving gentamicin therapy. The patients included those with normal renal function and those with varying degrees of renal impairment. The parameters studied were the apparent volume of distribution and the plasma clearance of gentamicin. The interindividual variability and the residual variability of those parameters in the different subpopulations were studied according to a statistical model that assumed log normal distribution. Use of the one-way ANOVA test revealed statistically significant differences (P = 0.004) in the population plasma clearance of gentamicin in patients below and above 50 years of age. A linear relationship was established between the plasma clearance of gentamicin and the creatinine clearance in those patients. At the same time, the coefficient of variation of the Clp increased progressively in patients with renal impairment, varying between 28.98% in patients with a ClCR greater than 100 ml/min and 76.53% in patients with a ClCR between 20 and 60 ml/min. The results obtained in the population study were later applied to drug monitoring in 23 patients with varying degrees of renal function and who received gentamicin therapy with different doses. The residual variability of the population allowed us to calculate a weighting factor (FF) between the experimental and the population data using Bayesian fitting. The weighting factor was 0.89 in patients with normal renal function and 0.80 in patients with renal impairment. Statistical comparison of the pharmacokinetic parameters obtained from the populational data, non-linear regression and the Bayesian method using revealed differences in the values for the apparent volume of distribution obtained with the two methods.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1985

Pharmacokinetics and initial distribution of a new neuroleptic agent picobenzide (M-14012-4).

The pharmacokinetics of picobenzide was studied in 14 adult patients undergoing neuroleptoanalgesic sessions. The dose of picobenzide administered was 10 mg/kg by i.v. injection. The pharmacokinetic parameters obtained revealed a good distribution capacity with an average value of the apparent distribution volume at steady state of 28.29 +/- 4.98 1. The drug was also seen to be eliminated rapidly from the organism with an average value of the serum half-life of 2.05 +/- 0.42 h. The determination of the initial distribution kinetics of picobenzide shows that the use of a conventional kinetic model induces an overestimation of the initial distribution volume in turn caused by an underestimation of the initial serum concentration.

Adult↗

PubMed1979

Pharmacokinetics of naproxen in healthy volunteers and in patients with diabetic microangiopathy.

The pharmacokinetics of Naproxen administered as a single oral dose of 250 mg, have been determined in 7 healthy volunteers and 9 patients who had been diagnosed as suffering from diabetes mellitus with varying degrees of angiopathy. A two-compartment model was used to describe the biphasic decline in serum concentrations and to calculate the amount of drug in the central and peripheral compartments. In healthy volunteers the following values were obtained for various pharmacokinetic parameters: tmax = 2 hr; Cmax = 52.63 micrograms/ml; Ka = 1.893 hr-1; alpha = 0.393 hr-1; beta = 0.049 hr-1; K12 = 0.147 hr-1; K21 = 0.198 hr-1; K13 = 0.097 hr-1. In patients with severe diabetic microangiopathy, a decrease may be seen in the fraction of the dose absorbed shown by a decrease in the Cmax and the (AUC) 0--8 hr. The glomerular impairment of some patients leads to a decrease in the elimination constant.

Adult↗

PubMedDate not supplied

[Cost-effectiveness of individualized enteral nutrition by a nutrition support team in laryngectomized cancer patients].

The purpose of this study was to evaluate the effectiveness of a Nutritional Support Team (NST) in the control and follow-up of enteral nutrition (EN) in patients subjected to laryngectomy as a result of neoplasia. The study was performed on two groups of patients (A and B) who had been admitted into the Otorhinolaryngological Department, and who required EN by nasogastric tube during the postoperative period. Group A consisted of 20 patients in whom EN was based on standard guidelines, with a daily intake of 11.1 g of Nitrogen and 2.000 kcals. Group B included 23 patients who received EN individually, using NST with a daily intake of Nitrogen of between 8 and 21 g, and energy intake of between 2.000 and 3.000 kcals. The total cost of nutrition was calculated using the following partial costs: diet, administration, laboratory analysis and NST head responsible for follow-up of Group B. Individualized EN was more effective in nutritional terms than a standard diet in all patients. Using this form of treatment, positive Nitrogen balance were achieved, levels of seric albumin were maintained as well as weight, and complications were reduced. The average cost of nutrition per patient in Group B was 46.258 pesetas and in Group A, 43.963 pesetas. However, in the latter Group, there was an average additional weight loss of 4 kg per patient, and an increase in cost effectiveness ratio of 573 pesetas in weight gained in Group B compared to Group A.

Adult↗