Biomedical subjects

L A Lavezo

Publications and source records attributed to L A Lavezo.

3 recordsLinked to original sources

PubMed2001

Step-down management of gastroesophageal reflux disease.

BACKGROUND & AIMS: As the economic burden of gastroesophageal reflux disease (GERD) is largely weighted to maintenance as opposed to initial therapy, switching from more potent to less expensive medication once symptoms are alleviated (step-down therapy) may prove to be most cost-effective. This study aimed to prospectively evaluate the feasibility of step-down therapy in a cohort of patients with symptoms of uncomplicated GERD. METHODS: Patients whose GERD symptoms were alleviated by proton pump inhibitors (PPIs) were recruited from outpatient general medicine clinics. After baseline demographic and quality of life information were obtained, PPIs were withdrawn from subjects in a stepwise fashion. Primary outcome was recurrence of symptoms during follow-up that required reinstitution of PPIs. Secondary outcomes included changes in quality of life and overall cost of management. Predictors of nonresponse to step-down were assessed. RESULTS: Seventy-one of 73 enrolled subjects completed the study. Forty-one of 71 (58%) were asymptomatic off PPI therapy after 1 year of follow-up. Twenty-four of 71 (34%) required histamine 2-receptor antagonists, 5/71 (7%) prokinetic agents, 1/71 (1%) both, and 11/71 (15%) remained asymptomatic without medication. Quality of life did not significantly change, whereas management costs decreased by 37%. Multivariable analysis revealed younger age and a dominant symptom of heartburn to predict PPI requirement. CONCLUSIONS: Step-down therapy is successful in the majority of patients and can decrease costs without adversely affecting quality of life.

Adult↗

PubMed1995

Vancomycin pharmacokinetics in spinal cord injured patients: a comparison with age-matched, able-bodied controls.

To compare the pharmacokinetics of vancomycin in chronic spinal cord injured patients and hospitalized, age-matched, able-bodied controls, we evaluated 14 spinal cord injured patients and 14 controls. Pharmacokinetic parameters of total body clearance (CL), distribution volume (V), elimination rate constant (k) and elimination half-life (t1/2) were calculated from two steady-state vancomycin serum concentrations by the method of Sawchuk and Zaske. Demographic data such as age, ideal body weight (IBW), total body weight (TBW) and serum creatinine at start of therapy (SCr), pharmacokinetic parameters and predicted dosages to achieve specific peak (30 mcg/ml) and through concentrations (5-10 mcg/ml) were calculated for both groups. Statistical comparisons were made using a two sample, Student's t-test. Demographic data between groups differed only in mean serum creatinine (p = 0.04). There were no statistically significant differences in mean pharmacokinetic parameters of CL and V or mean predicted dosages. Mean elimination rate constant was significantly smaller and mean elimination half-life was significantly longer in spinal cord injured patients (p = 0.02 and p = 0.04, respectively). The longer dosing interval predicted in spinal cord injured patients trended toward statistical significance (p = 0.10). We conclude that with chronic spinal cord injury, 1) the elimination half-life of vancomycin is increased and these patients may require longer dosing intervals and 2) distribution volume and predicted vancomycin doses are unaltered compared with controls.

Adult↗

PubMed1994

Two-versus three-sample method for estimating gentamicin pharmacokinetic values.

The performances of two-sample and three-sample methods for estimating gentamicin pharmacokinetic values were studied. The medical records of patients who had received a gentamicin dosage consultation at a Veterans Affairs medical center between June 1989 and May 1991 were reviewed. For each patient, the pharmacokinetics service had prospectively used three serum gentamicin concentrations (SGCs) determined from three blood samples taken during an initial gentamicin regimen to estimate gentamicin pharmacokinetic values and determine the alternative would achieve the desired SGCs. In the two-sample method, the authors retrospectively used the initial peak and trough SGCs determined from two blood samples to estimate pharmacokinetic values and establish an alternative regimen. The two methods were evaluated by comparing their results with each other and with the actual pharmacokinetic values determined from SGCs measured during the subsequent gentamicin regimen. A total of 27 patients (all men; mean age, 62 years) were included in the study. The two-sample and three-sample methods differed significantly in their estimates of elimination rate constant and half-life but not clearance, volume of distribution, or the daily dose needed to achieve the intended SGCs. Neither method produced estimates that differed significantly from the actual pharmacokinetic values. The three-sample method was less biased than the two-sample method in the prediction of trough SGCs. In middle-aged and elderly men, a two-sample method and a three-sample method of estimating gentamicin pharmacokinetics differed significantly only in the prediction of trough SGCs. The difference was probably not clinically important.

Aged↗