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Biomedical subjects

Josep Ribas

Publications and source records attributed to Josep Ribas.

9 recordsLinked to original sources
PubMed2006

Are higher vancomycin doses needed in ventricle-external shunted patients?

OBJECTIVE: Hydrocephalus is usually resolved by diverting cerebrospinal fluid through a surgically implanted intra-ventricular catheter (shunt). The aim of this study was to characterize vancomycin pharmacokinetic (PK) parameters and optimal dosage in shunted patients under vancomycin treatment. SETTING: Intensive Care and Neurosurgical Units. University Hospital. METHODS: Retrospective data of vancomycin blood concentrations, demographics and biochemical parameters, from a Therapeutic Drug Monitoring (TDM) program, in ventricle-external shunted patients (Group A) and controls (Group B) were collected. In all subjects, several blood samples at steady state conditions were drawn. Individual PK parameters such as drug clearance (CL) and volume of distribution (V) were estimated by using an one-compartmental PK model and later, dosage regimens were individually adjusted by Bayesian analysis. The obtained CL and V mean +/- standard deviation were compared between both groups (A versus B). Vancomycin dosage regimens between both groups were also compared. MAIN OUTCOME MEASURES: Patients demographics, clinical records, creatinine clearance by Cockcroft-Gault, vancomycin blood levels, vancomycin pK parameters and optimal initial IV vancomycin dosage. RESULTS: Forty-five patients were included in the study: 15 patients in group A and 30 subjects in group B. Significant differences between CL(A) and CL(B) means were observed, while not between V(A) and V(B). In shunted patients, the required vancomycin daily dose to reach target concentrations was significantly higher than the dose needed in the control group (49.25 +/- 12.28 mg/kg/day vs. 31.74 +/- 6.70 mg/kg/day; P < 0.0005). CONCLUSIONS: Greater vancomycin clearance was found in our shunted patients, thus they required higher vancomycin daily doses compared to the control group. Consequently, vancomycin TDM in shunted patients should be advisable in order to guarantee antibiotic blood concentrations within the recommended therapeutic range.

Adult↗
PubMed2006

[Antiretroviral therapy of HIV infection: duration and reasons for changing the first therapeutic regimen in 518 patients].

BACKGROUND AND OBJECTIVE: Different combinations of antiretroviral drugs are used as initial HIV therapy but comparative studies between them are not frequent. The objectives of this study are to determine the median duration of different therapy combinations in naive patients between 1998-2000 and the main reasons for changing or stopping this first antiretroviral therapy (ARVT). PATIENTS AND METHOD: This study included a total of 518 naive patients who began antiretroviral therapy patients from 1998-2000. Using a Kaplan-Meier analysis the median duration of different combinations was determined. In addition, the main reasons for changing or stopping this first treatment were analysed. RESULTS: First ARVT median duration was 427 days (IQR: 114-890). 47% of patients stopped their first therapy due to adverse effects, 6% voluntarily withdrew from it, in 9% of patients the therapy was not effective and 15% of them were lost of follow up. Only 9% of them continued with the same ARVT at the end of the study but if we add 7% of treatment simplifications we can consider 16% of first ARVT successful. CONCLUSIONS: A median duration of 427 days, similar to other studies, is shorter than we would prefer for HIV, a condition that requires continuous treatment. On the other hand, the study corroborates that secondary effects are the principal problem associated with ARVT.

Adult↗
PubMed2006

Teicoplanin population pharmacokinetic analysis in hospitalized patients.

The goal of this study was to build a population pharmacokinetic (PK) model to characterize the population PK parameters in our hospitalized patients. Teicoplanin serum concentrations from clinical routine were used. Antibiotic dose history and blood collection times were recorded and analyzed with NONMEM-V. Demographic and biologic data creatinine clearance (CLcr), weight (WT), and albumin (Alb) were tested for inclusion as covariates in the basic model. Intraindividual and residual variability were modeled. One hundred seven sparse samples (mainly trough levels), from 79 patients, were included. A 2-compartment PK model characterized by clearance (CL), central compartment volume of distribution (Vc), intercompartment clearance, and steady-state volume of distribution (VSS) with first-order elimination adequately described the data. CLcr and WT significantly influenced teicoplanin CL (CL = 0.57[0.15]*(1+0.0048[0.39]*(CLcr - averageCLcr)*WT) L/h). VSS was not affected by any covariate (VSS = 50.2[0.13]L). A negative trend between Alb and individual VSS estimates was observed without statistical significance. In a new data set, bias and precision resulted in mean values of -3.24% and 9.42%, respectively. In conclusion, CLcr and WT are significant covariates on teicoplanin CL. Results from predictive accuracy and precision show the usefulness of this model for implementation in a therapeutic drug monitoring program in the near future.

Adult↗
PubMed2004

Tirofiban and eptifibatide treatment of patients presenting with acute coronary syndrome with non-ST segment elevation.

OBJECTIVE: This retrospective study was conducted to determine the usage patterns and tolerability of tirofiban and eptifibatide during the first year of their use. METHODS: We have assessed the appropriate use of these drugs according to the criteria implemented by the Clinical Institute of Cardiovascular Disease as part of a protocol for treating acute coronary syndrome with non-ST segment elevation. RESULTS: 37 patients received tirofiban and 19 patients received eptifibatide. These patients were at high risk of poor outcomes such as myocardial infarction or death. Tirofiban and eptifibatide were used according to the indication criteria: only one case fell outside them. Dosing, time for drug initiation (from last chest pain) and time of infusion were considered appropriate. Tirofiban was involved in two cases of minor bleeding complications and eptifibatide in one case of thrombocytopenia (80,000 platelets per millimeter). These mild adverse drug reactions were reversible with the early withdrawal of the drugs. CONCLUSIONS: This study shows that tirofiban and eptifibatide have been used optimally, with a close adherence to the pre-established protocol. Both drugs have shown a good level of tolerability.

Acute Disease↗
PubMed2003

[Characteristics of antiviral drugs].

This article summarizes the principal characteristics of the drugs used to treat viral infections, with the exception of human immunodeficiency virus infection. It includes antiviral agents active against herpes virus, cytomegalovirus, hepatitis B and C virus, and respiratory viruses, such as influenza and respiratory syncytial virus. Dosage according to the indication, dose adjustment in the case of renal or hepatic insufficiency, significant pharmacokinetic characteristics, and the main adverse effects and interactions are described.

Antiviral Agents↗
PubMed2002

[Drug related problems as a cause of hospital admission].

BACKGROUND: The goals of the present study were: a) to identify and characterize drug-related problems (adverse drug reactions, non-compliance and intentional overdose) leading to admissions to our hospital (Hospital Clínic) through the Emergency Department, b) to know the most frequently involved medications, c) to identify risk factors for hospital admissions due to drug-related problems, and d) to determine the avoidability of these admissions. PATIENTS AND METHOD: Prospective study carried out from August 1999 to November 1999 and from January 2000 to May 2000. The study included 1,800 admissions corresponding to 1,663 patients. RESULTS: Including definitive, probable and possible cases, 215 hospital admissions (11.9%) were drug-related ones. Of these cases, 108 (50.2%) corresponded to adverse drug reactions, 100 (46.5%) to dose-related therapeutic failures (mainly non-compliance) and 7 (3.3%) corresponded to intentional overdose. When 'possible' cases were excluded in order to achieve a better defined causative relationship, drug-related admissions dropped to 139 (7.7%). According to Schumock and Thornton criteria, 68.4% hospital admissions due to drug-related problems were considered 'avoidable'. Most avoidable admissions were due to non-compliance, absence of preventive therapy and inappropriate monitoring. CONCLUSIONS: Hospital admissions due to drug-related problems are frequent and often preventable.

Aged↗
PubMed2002

[Comparison of three methods to calculate adherence in patients receiving antiretroviral treatment].

INTRODUCTION: Knowledge of the patient's adherence to antiretroviral treatment is extremely useful for monitoring HIV infection. Several methods have been proposed to calculate adherence, but they all have certain problems at application. The aim of this study was to compare three of the available methods for assessing medication adherence in order to determine their accuracy for this purpose. PATIENTS AND METHODS: Three methods for evaluating medication adherence were prospectively studied: 1. Remaining pill count (RPC), 2. Structured interview (SI), and 3. Pharmacy registry of drug refills (DR). The RPC was considered the gold standard and sensitivity and specificity of the other methods was calculated according to the RPC. The study included 100 consecutive patients and had a follow-up of one year. RESULTS: We were able to assess all three methods in 69 cases. The percentages of patients taking 95% or more of the prescribed dose according to the three methods were 72.5% (RPC), 85.5% (SI) and 81.2% (DR). Taking the RPC as gold standard, there was 75.1% concordance with the DR and 75.1% with the SI method. The sensitivities of the DM and SI were 52.6 % and 42.1 %, respectively. After one year of follow-up, patients with > 90% adherence (RPC) had a 1.29-times higher probability of achieving good virological response (CI 95% 1.04-1.62, p 5 0.0138). CONCLUSION: Although concordance among the methods was acceptable, the SI and DR overestimated adherence as compared to the RPC. Since there is currently no ideal method for determining treatment adherence, it is important to combine several methods to minimize errors and provide results that are as close to the true situation as possible.

Adult↗
PubMedDate not supplied

[Reflections on betalactam antibiotics administered by continuous infusion].

Numerous studies on continuous intravenous infusion of betalactam antibiotics have indicated that this could be a useful strategy for treating nosocomial infections as well as exacerbations of pulmonary infections in patients with cystic fibrosis and episodes of febrile neutropenia. From the pharmacodynamic viewpoint, betalactam antibiotics have a time-dependent behavior. Thus, the pharmacokinetic/pharmacodynamic index that best correlates with therapeutic efficacy appears to be the time during which free antibiotic concentrations remain above the minimum inhibitory concentration (MIC) of the infecting microorganism. Continuous infusion of betalactams successfully optimizes this pharmacokinetic/ pharmacodynamic index. Furthermore, some studies have shown that this therapeutic strategy may be favorable economically.

Anti-Bacterial Agents↗