Bayesian Models for Therapeutic Monitoring of Vancomycin in the Critically Ill: What Should They Predict?

Panagiotis Briassoulis; George Briassoulis

doi:10.1097/ccm.0000000000005228

Vancomycin Prescribing Practices and Therapeutic Drug Monitoring for Critically Ill Neonatal and Pediatric Patients: A Survey of Physicians and Pharmacists in Hong Kong

Frontiers in Pediatrics ◽

10.3389/fped.2020.538298 ◽

2020 ◽

Vol 8 ◽

Author(s):

Twinny Cheuk Hin Chow ◽

Janice Yuen Shun Li ◽

Jasper Chak Ling Wong ◽

Freddie Man Hong Poon ◽

Hugh Simon Lam ◽

...

Keyword(s):

Hong Kong ◽

Critically Ill ◽

Pediatric Patients ◽

Pediatric Population ◽

Therapeutic Monitoring ◽

Therapeutic Drug ◽

Prescribing Practices ◽

Cross Sectional ◽

The Impact ◽

Trough Levels

Background: Deviations from the optimal vancomycin dosing may occur in the neonatal and pediatric population due to inconsistencies in the recommended dosing algorithms. This study aims to collect the expert opinions of clinicians who practice in the neonatal or pediatric intensive care units (NICU/PICUs) of 12 major medical centers in Hong Kong.Methods: This was a multicenter, cross-sectional study. Eligible physicians and pharmacists completed a structured questionnaire to identify the challenges they encountered when selecting the initial intermittent vancomycin dosing. They also answered questions concerning therapeutic monitoring services (TDM) for vancomycin, including the targeted trough levels for empirical vancomycin regimens administered for complicated and uncomplicated infections.Results: A total of 23 physicians and 43 pharmacists completed the survey. The top clinical parameters reported as most important for determining the initial vancomycin dosing were renal function (90.9%), post-menstrual/postnatal age (81.8%), body weight (66.7%), and suspected/documented pathogen (53.0%). Respondents reported challenges such as difficulties in determining the optimal initial dose for a targeted level (53.0%), inconsistencies between dosing references (43.9%) and a lack of clear hospital guidelines (27.3%). Half of the pharmacists (48.8%) reported that they had helped to interpret the TDM results and recommend vancomycin dose adjustments in >75% of cases. For methicillin-resistant Staphylococcus aureus infection, physicians, and pharmacists reported target trough levels of ~10–15 and 15–20 mg/L, respectively. For suspected moderate/uncomplicated Gram-positive infections physicians tended to prefer a lower trough range of 5–10 mg/L, while pharmacists preferred a range of 10–15 mg/L.Conclusions: Our results demonstrate that clinicians used varying vancomycin dosing guidelines in their practices. The multidisciplinary TDM service in Hong Kong can be improved further by establishing a standardized dosing guideline and implementing a well-structured, evidence-based service protocol. Future work includes conducting drug utilization studies to evaluate real-world antimicrobial usage patterns and the impact on tangible clinical outcomes, and developing pharmacokinetic-guided dose calculator for antimicrobials in critically ill neonates and pediatric patients.

Download Full-text

Vancomycin therapeutic monitoring by measured trough concentration versus Bayesian‐derived area under the curve in critically ill patients with cancer

Pharmacology Research & Perspectives ◽

10.1002/prp2.912 ◽

2022 ◽

Vol 10 (1) ◽

Author(s):

Aseel K. AbuSara ◽

Deema H. Abdelrahman ◽

Khader I. Habash ◽

Mohammad H. Al‐Shaer ◽

Jennifer Le ◽

...

Keyword(s):

Critically Ill ◽

Trough Concentration ◽

Critically Ill Patients ◽

Area Under The Curve ◽

Therapeutic Monitoring ◽

Patients With Cancer

Download Full-text

Therapeutic Monitoring: Revised Winter–Tozer Equation for Normalized Phenytoin Concentrations in Trauma and Elderly Patents with Hypoalbuminemia

Annals of Pharmacotherapy ◽

10.1177/106002809703100301 ◽

1997 ◽

Vol 31 (3) ◽

pp. 279-284 ◽

Cited By ~ 39

Author(s):

Gail D Anderson ◽

Christopher Pak ◽

Kenneth W Doane ◽

Kay G Griffy ◽

Nancy R Temkin ◽

...

Keyword(s):

Nursing Home ◽

Critically Ill ◽

Prediction Error ◽

Mean Squared Error ◽

Therapeutic Monitoring ◽

Controlled Study ◽

Trauma Patients ◽

Double Blind ◽

Double Blind Placebo ◽

Nursing Home Patients

Objective To develop a revised equation reflecting the current practice of measuring unbound phenytoin at room temperature, and to evaluate the revised Winter–Tozer method of predicting normalized total phenytoin concentrations in two groups of patients with hypoalbuminemia — elderly nursing home patients and critically ill head trauma patients. Design Albumin, unbound phenytoin, and total phenytoin concentrations were obtained from two sources: prospectively from a group of elderly nursing home patients and by a retrospective chart review of trauma patients enrolled in a previous double-blind, placebo-controlled study. Setting Community nursing homes; a university-affiliated urban teaching hospital. Participants Elderly nursing home patients (n = 46) taking chronic phenytoin therapy and patients enrolled in a double-blind, placebo-controlled study (n = 58) evaluating the use of phenytoin to prevent posttraumatic seizures. Main Outcome Measures Prediction error analysis was performed by using the methods proposed by Sheiner and Beal. Bias and precision were evaluated by calculating the mean prediction error (MPE) and root mean squared error (RMSE), respectively. Results The Winter–Tozer equation consistently overpredicted the normalized phenytoin concentration in the elderly nursing home population (MPE = 3.2, RMSE = 5.9) and the trauma patients (MPE = 3.3, RMSE = 4.8). The equation was revised to reflect the increased protein binding of phenytoin with decreased temperature and resulted in significantly decreased bias in both groups of patients. Conclusions The revised equation is useful in predicting normalized phenytoin concentrations in both elderly nursing home patients and critically ill trauma patients.

Download Full-text