Clinician adherence to pharmacogenomics prescribing recommendations in clinical decision support alerts

Thoughtful integration of interruptive clinical decision support (CDS) alerts within the electronic health record is essential to guide clinicians on the application of pharmacogenomic results at point of care. St. Jude Children's Research Hospital implemented a preemptive pharmacogenomic testing program in 2011 in a multidisciplinary effort involving extensive education to clinicians about pharmacogenomic implications. We conducted a retrospective analysis of clinicians' adherence to 4783 pharmacogenomically guided CDS alerts that triggered for 12 genes and 60 drugs. Clinicians adhered to the therapeutic recommendations provided in 4392 alerts (92%). In our population of pediatric patients with catastrophic illnesses, the most frequently presented gene/drug CDS alerts were TPMT/NUDT15 and thiopurines (n = 3850), CYP2D6 and ondansetron (n = 667), CYP2D6 and oxycodone (n = 99), G6PD and G6PD high-risk medications (n  = 51), and CYP2C19 and proton pump inhibitors (omeprazole and pantoprazole; n = 50). The high adherence rate was facilitated by our team approach to prescribing and our collaborative CDS design and delivery.

Incorporating G6PD genotyping to identify patients with G6PD deficiency

Glucose-6-phosphate-dehydrogenase (G6PD) deficiency is a common X-linked enzyme disorder associated with hemolytic anemia after exposure to fava beans or certain medications. Activity testing is the gold standard for detecting G6PD deficiency; however, this test is affected by various hematologic parameters. Clinical G6PD genotyping is now included in pharmacogenetic arrays and clinical sequencing efforts and may be reconciled with activity results. Patients (n = 1391) enrolled on an institutional pharmacogenetic testing protocol underwent clinical G6PD genotyping for 164 G6PD variants. An algorithm accounting for known interferences with the activity assay is proposed. We developed clinical decision support alerts to inform prescribers when high-risk medications were prescribed, warning of gene-drug interactions and recommending therapy alteration. Of 1391 patients with genotype results, 1334 (95.9%) patients were predicted to have normal G6PD activity, 30 (2.1%) were predicted to have variable G6PD activity and 27 (2%) were predicted to have deficient G6PD activity. Of the 417 patients with a normal genotype and an activity result, 415 (99.5%) had a concordant normal G6PD phenotype. Of the 21 patients with a deficient genotype and an activity result, 18 (85.7%) had a concordant deficient activity result. Genotyping reassigned phenotype in five patients with discordant genotype and activity results: three switched from normal to deficient, and two switched from deficient to normal. G6PD activity and genotyping are two independent testing methods that can be used in conjunction to assign a more informed G6PD phenotype than either method alone.

Optimizing Drug-Drug Interaction Alerts Using a Multidimensional Approach

OBJECTIVES

Excessive alerts are a common concern associated with clinical decision support systems that monitor drug-drug interactions (DDIs). To reduce the number of low-value interruptive DDI alerts at our hospital, we implemented an iterative, multidimensional quality improvement effort, which included an interdisciplinary advisory group, alert metrics, and measurement of perceived clinical value.

METHODS

Alert data analysis indicated that DDIs were the most common interruptive medication alert. An interdisciplinary alert advisory group was formed to provide expert advice and oversight for alert refinement and ongoing review of alert data. Alert data were categorized into drug classes and analyzed to identify DDI alerts for refinement. Refinement strategies included alert suppression and modification of alerts to be contextually aware.

RESULTS

On the basis of historical analysis of classified DDI alerts, 26 alert refinements were implemented, representing 47% of all alerts. Alert refinement efforts resulted in the following substantial decreases in the number of interruptive DDI alerts: 40% for all clinicians (22.9-14 per 100 orders) and as high as 82% for attending physicians (6.5-1.2 per 100 orders). Two patient safety events related to alert refinements were reported during the project period.

CONCLUSIONS

Our quality improvement effort refined 47% of all DDI alerts that were firing during historical analysis, significantly reduced the number of DDI alerts in a 54-week period, and established a model for sustained alert refinements.

Using EHR Data to Detect Prescribing Errors in Rapidly Discontinued Medication Orders

BACKGROUND

Previous research developed a new method for locating prescribing errors in rapidly discontinued electronic medication orders. Although effective, the prospective design of that research hinders its feasibility for regular use.

OBJECTIVES

Our objectives were to assess a method to retrospectively detect prescribing errors, to characterize the identified errors, and to identify potential improvement opportunities.

METHODS

Electronically submitted medication orders from 28 randomly selected days that were discontinued within 120 minutes of submission were reviewed and categorized as most likely errors, nonerrors, or not enough information to determine status. Identified errors were evaluated by amount of time elapsed from original submission to discontinuation, error type, staff position, and potential clinical significance. Pearson's chi-square test was used to compare rates of errors across prescriber types.

RESULTS

In all, 147 errors were identified in 305 medication orders. The method was most effective for orders that were discontinued within 90 minutes. Duplicate orders were most common; physicians in training had the highest error rate (p < 0.001), and 24 errors were potentially clinically significant. None of the errors were voluntarily reported.

CONCLUSION

It is possible to identify prescribing errors in rapidly discontinued medication orders by using retrospective methods that do not require interrupting prescribers to discuss order details. Future research could validate our methods in different clinical settings. Regular use of this measure could help determine the causes of prescribing errors, track performance, and identify and evaluate interventions to improve prescribing systems and processes.

Pharmacogenetics for Safe Codeine Use in Sickle Cell Disease

After postoperative deaths in children who were prescribed codeine, several pediatric hospitals have removed it from their formularies. These deaths were attributed to atypical cytochrome P450 2D6 (CYP2D6) pharmacogenetics, which is also implicated in poor analgesic response. Because codeine is often prescribed to patients with sickle cell disease and is now the only Schedule III opioid analgesic in the United States, we implemented a precision medicine approach to safely maintain codeine as an option for pain control. Here we describe the implementation of pharmacogenetics-based codeine prescribing that accounts for CYP2D6 metabolizer status. Clinical decision support was implemented within the electronic health record to guide prescribing of codeine with the goal of preventing its use after tonsillectomy or adenoidectomy and in CYP2D6 ultra-rapid and poor metabolizer (high-risk) genotypes. As of June 2015, CYP2D6 genotype results had been reported for 2468 unique patients. Of the 830 patients with sickle cell disease, 621 (75%) had a CYP2D6 genotype result; 7.1% were ultra-rapid or possible ultra-rapid metabolizers, and 1.4% were poor metabolizers. Interruptive alerts recommended against codeine for patients with high-risk CYP2D6 status. None of the patients with an ultra-rapid or poor metabolizer genotype were prescribed codeine. Using genetics to tailor analgesic prescribing retained an important therapeutic option by limiting codeine use to patients who could safely receive and benefit from it. Our efforts represent an evidence-based, innovative medication safety strategy to prevent adverse drug events, which is a model for the use of pharmacogenetics to optimize drug therapy in specialized pediatric populations.

Thirty-day readmissions following adult spinal deformity surgery: an analysis of the National Surgical Quality Improvement Program (NSQIP) database

BACKGROUND

Adult spine deformity surgery (ASDS) is a significantly invasive procedure with a relatively high complication rate. The thirty-day hospital readmission rate following surgery is an important quality measure monitored by multiple quality reporting agencies.

PURPOSE

This study seeks to determine the risk factors for 30- day readmission rate in patients undergoing ASDS and identify the risk factors associated with readmission.

STUDY DESIGN

This is a retrospective multicenter study.

METHODS

The National Surgical Quality Improvement Program database, which is a large multi-institutional database, was searched for patients that underwent ASDS from 2011 to 2013. The patients were identified by searching seven Current Procedural Terminology codes most commonly used for spinal deformity surgery. Twenty-seven preoperative variables, including patient demographics and comorbidities, intraoperative parameters, and postoperative complications were analyzed to identify risk factors for readmission.

RESULTS

A total of 747 adult patients who underwent ASDS were identified. Of the 747 patients, 7.5% (56/747) were readmitted within 30 days. The most common causes of readmission were infection (n=11), hematoma or seroma formation (n=5), and postoperative pain (n=3). Univariate analysis revealed male gender (p=.038, odds ratio [OR]=1.83) and pulmonary embolism before discharge (p=.048, OR=8.44) to be associated with readmission. In multivariate analysis, obesity (p=.047, OR=1.80), peripheral vascular disease (p=.045, OR=17.52), pulmonary embolism before discharge (p=.012, OR=10.35), and total or partial dependent preoperative functional health status (p=.041, OR=2.45), were found to be independent risk factors for readmission. Age, smoking, and resident involvement during surgical procedure were among the many factors not associated with increased risk of readmission.

CONCLUSIONS

The 30-day readmission rate for ASDS is increasingly becoming a significant health-care quality indicator. Patients with the aforementioned significant risk factors should be closely followed up, which can potentially avoid subsequent readmission.

Alert dwell time: introduction of a measure to evaluate interruptive clinical decision support alerts

Metrics for evaluating interruptive prescribing alerts have many limitations. Additional methods are needed to identify opportunities to improve alerting systems and prevent alert fatigue. In this study, the authors determined whether alert dwell time-the time elapsed from when an interruptive alert is generated to when it is dismissed-could be calculated by using historical alert data from log files. Drug-drug interaction (DDI) alerts from 3 years of electronic health record data were queried. Alert dwell time was calculated for 25,965 alerts, including 777 unique DDIs. The median alert dwell time was 8 s (range, 1-4913 s). Resident physicians had longer median alert dwell times than other prescribers (P < 001). The 10 most frequent DDI alerts (n = 8759 alerts) had shorter median dwell times than alerts that only occurred once (P < 001). This metric can be used in future research to evaluate the effectiveness and efficiency of interruptive prescribing alerts.

PG4KDS: a model for the clinical implementation of pre-emptive pharmacogenetics

Pharmacogenetics is frequently cited as an area for initial focus of the clinical implementation of genomics. Through the PG4KDS protocol, St. Jude Children's Research Hospital pre-emptively genotypes patients for 230 genes using the Affymetrix Drug Metabolizing Enzymes and Transporters (DMET) Plus array supplemented with a CYP2D6 copy number assay. The PG4KDS protocol provides a rational, stepwise process for implementing gene/drug pairs, organizing data, and obtaining consent from patients and families. Through August 2013, 1,559 patients have been enrolled, and four gene tests have been released into the electronic health record (EHR) for clinical implementation: TPMT, CYP2D6, SLCO1B1, and CYP2C19. These genes are coupled to 12 high-risk drugs. Of the 1,016 patients with genotype test results available, 78% of them had at least one high-risk (i.e., actionable) genotype result placed in their EHR. Each diplotype result released to the EHR is coupled with an interpretive consult that is created in a concise, standardized format. To support-gene based prescribing at the point of care, 55 interruptive clinical decision support (CDS) alerts were developed. Patients are informed of their genotyping result and its relevance to their medication use through a letter. Key elements necessary for our successful implementation have included strong institutional support, a knowledgeable clinical laboratory, a process to manage any incidental findings, a strategy to educate clinicians and patients, a process to return results, and extensive use of informatics, especially CDS. Our approach to pre-emptive clinical pharmacogenetics has proven feasible, clinically useful, and scalable.

Development and use of active clinical decision support for preemptive pharmacogenomics

Background

Active clinical decision support (CDS) delivered through an electronic health record (EHR) facilitates gene-based drug prescribing and other applications of genomics to patient care.

Objective

We describe the development, implementation, and evaluation of active CDS for multiple pharmacogenetic test results reported preemptively.

Materials and methods

Clinical pharmacogenetic test results accompanied by clinical interpretations are placed into the patient's EHR, typically before a relevant drug is prescribed. Problem list entries created for high-risk phenotypes provide an unambiguous trigger for delivery of post-test alerts to clinicians when high-risk drugs are prescribed. In addition, pre-test alerts are issued if a very-high risk medication is prescribed (eg, a thiopurine), prior to the appropriate pharmacogenetic test result being entered into the EHR. Our CDS can be readily modified to incorporate new genes or high-risk drugs as they emerge.

Results

Through November 2012, 35 customized pharmacogenetic rules have been implemented, including rules for TPMT with azathioprine, thioguanine, and mercaptopurine, and for CYP2D6 with codeine, tramadol, amitriptyline, fluoxetine, and paroxetine. Between May 2011 and November 2012, the pre-test alerts were electronically issued 1106 times (76 for thiopurines and 1030 for drugs metabolized by CYP2D6), and the post-test alerts were issued 1552 times (1521 for TPMT and 31 for CYP2D6). Analysis of alert outcomes revealed that the interruptive CDS appropriately guided prescribing in 95% of patients for whom they were issued.

Conclusions

Our experience illustrates the feasibility of developing computational systems that provide clinicians with actionable alerts for gene-based drug prescribing at the point of care.

Safe and successful implementation of CPOE for chemotherapy at a children's cancer center

Computerized prescriber order entry (CPOE) for medications has been implemented in only approximately 1 in 6 United States hospitals, with CPOE for chemotherapy lagging behind that for nonchemotherapy medications. The high risks associated with chemotherapy combined with other aspects of cancer care present unique challenges for the safe and appropriate use of CPOE. This article describes the process for safe and successful implementation of CPOE for chemotherapy at a children's cancer center. A core principle throughout the development and implementation of this system was that it must be as safe (and eventually safer) as existing paper systems and processes. The history of requiring standardized, regimen-specific, preprinted paper order forms served as the foundation for safe implementation of CPOE for chemotherapy. Extensive use of electronic order sets with advanced functionality; formal process redesign and system analysis; automated clinical decision support; and a phased implementation approach were essential strategies for safe implementation of CPOE. With careful planning and adequate resources, CPOE for chemotherapy can be safely implemented.

Development and implementation of a pharmacist-managed clinical pharmacogenetics service

PURPOSE

The development and implementation of a pharmacist-managed clinical pharmacogenetics service are described.

SUMMARY

A pharmacist-managed clinical pharmacogenetics service was designed and implemented at an academic specialty hospital to provide clinical pharmacogenetic testing for gene products important to the pharmacodynamics of medications used in the hospital's patients. A series of accredited educational seminars were conducted for our pharmacists to establish competencies in providing pharmacogenetic consults for the genes to be tested by the clinical pharmacogenetics service. The service was modeled after and integrated with an already-established clinical pharmacokinetics service. A steering committee was formed to evaluate the use of available tests, new evidence for implementation of additional tests, and other service quality metrics. All clinical pharmacogenetic test results are first reported to one of the pharmacists, who reviews the result and provides a written consultation. The consultation includes an interpretation of the result and recommendations for any indicated changes to therapy. In 2009, 136 clinical pharmacogenetic tests were performed. The service has been met with positive clinician feedback. The successful implementation of this service highlights the leadership role that pharmacists can take in moving pharmacogenetics from research to patient care.

CONCLUSION

The development of and experience with a pharmacist-managed clinical pharmacogenetics service are described. The program's success has depended on collaboration between the clinical laboratory and pharmacists, and pharmacists' pharmacogenetic recommendations have been well accepted by prescribers.

Oral cefixime is similar to continued intravenous antibiotics in the empirical treatment of febrile neutropenic children with cancer

Empiric oral antibiotic therapy for febrile neutropenic cancer patients has been suggested as a means to decrease hospitalization, but the safety of this approach has not been adequately studied in children. We compared continued iv antibiotic therapy with switching treatment to orally administered cefixime in a group of selected febrile neutropenic children for whom blood cultures were sterile after 48 h of incubation. Two hundred episodes of febrile neutropenia were studied (156 patients), and 100 episodes were randomized to receive each treatment. Failure to respond to therapy was defined by documented or suspected bacterial infection, recurrent fever, or discontinuation of assigned therapy for any reason before neutropenia resolved. Rates of treatment failure were similar in the oral cefixime group (28%) and in the iv antibiotic group (27%; P=1.0). Results support the safety of oral cefixime therapy for low-risk febrile neutropenic children, a therapeutic approach that would facilitate earlier outpatient management and decrease the costs of treatment.

Pharmacokinetics of azithromycin after single- and multiple-doses in children

STUDY OBJECTIVE

To characterize the disposition and tolerance of azithromycin after single and multiple oral doses of 12 mg/kg in children with and without cancer.

DESIGN

Open-label, nonrandomized pharmacokinetic study.

SETTING

Two pediatric hospitals.

PATIENTS

Twelve children with cancer admitted to the inpatient unit for empiric antibiotic treatment of febrile neutropenia, and 16 hospitalized patients receiving antibiotic therapy

INTERVENTIONS

Patients received azithromycin suspension either as a single dose or daily dose every morning for 5 consecutive days. Serial blood samples were collected up to 120 hours after a single dose or during and after multiple doses to characterize the pharmacokinetic parameters estimated for a two-compartment absorption model.

MEASUREMENTS AND MAIN RESULTS

All 28 patients were evaluable for safety. Azithromycin was well tolerated except in one patient with cancer who experienced abdominal cramps and withdrew from the study. Pharmacokinetic results were not determined in five patients because of insufficient concentration-time data. The mean +/- SD estimates of oral clearance, terminal half-life, maximum concentration in serum (Cmax), and time to achieve Cmax in the 23 evaluable patients were 4.83 +/- 3.59 L/hour/kg, 54.5 +/- 36.4 hours, 318.2 +/- 174.5 microg/L, and 2.4 +/- 1.1 hours, respectively. These estimates did not differ between single-dose (14 patients) and multiple-dose (9 patients) groups. Pharmacokinetic parameters were not different between the 11 children with cancer and the 12 without cancer.

CONCLUSION

Azithromycin 12 mg/kg results in proportionately higher serum concentrations than previously published results for lower doses (5 mg/kg). Variability in concentration profiles among patients is substantial, and age or other yet unidentified clinical factors may explain some of the differences observed.

Effect of helical CT on the frequency of sedation in pediatric patients

OBJECTIVE

We compared the use of sedation for helical CT examination of pediatric patients with that for conventional CT studies.

MATERIALS AND METHODS

We retrospectively compared two 4-month periods of CT examinations that differed only in that conventional CT was routinely used in one period and helical CT was exclusively used in the other period. For these two periods, we compared the type and number of CT examinations, the sedation used (if any), and the age of patients who required sedation.

RESULTS

We performed 1055 conventional CT examinations in 762 pediatric cancer patients. Of the 264 children who were 8 years old or younger, 107 had been sedated. In comparison, 1195 helical CT examinations were performed on 838 patients: of the 246 children 8 years old or younger, 51 received sedation. For both study groups, the mean and median age of the patients was 4 years old. The mean age of patients requiring sedation was 21 (conventional CT) or 20 months (helical CT); the median age of patients who required sedation was 2 years old for both study groups. Patients who were 8 years old or younger and who underwent helical CT required sedation 49% less frequently than such patients who underwent conventional CT. The most dramatic reduction occurred among patients who were 3 years old or younger (p < or = .004).

CONCLUSION

Use of helical CT reduced the need for sedation among our pediatric patients. Fewer sedations may reduce the risk of complications, decrease disruption of the patient's normal daily activities, and improve patient throughout. The associated savings in personnel time and pharmaceutical costs can be redistributed.

Patient-controlled analgesia with fentanyl in children

We have found that fentanyl delivered by PCA provides an effective alternative when adverse effects occur with other more frequently used narcotics. Although anecdotal experience exists concerning the use of fentanyl PCA in adults, dosing guidelines in children must depend on consideration of the current narcotic regimen and the use of equipotent doses of fentanyl. Our initial experience suggests that this is a safe and reliable technique; however, until prospective studies further delineate dosing guidelines, close observation (continuous pulse oximetry and hourly checks of respiratory rate) of these patients is recommended. With such caveats, fentanyl PCA appears to provide an acceptable alternative to "more conventional" narcotics.

Increased teniposide clearance with concomitant anticonvulsant therapy

PURPOSE

A possible pharmacokinetic interaction between teniposide and anticonvulsant medications was evaluated in pediatric patients.

PATIENTS AND METHODS

The systemic clearance of teniposide was determined in six pediatric patients with acute lymphocytic leukemia receiving concomitant therapy with anticonvulsants. Clearance was then compared with a control group of patients treated with the same protocol therapy and matched for age at diagnosis, sex, and race but not receiving anticonvulsants or other agents known to induce hepatic metabolism or alter protein binding of drugs. Eight blood samples were obtained during and after 4-hour infusions of teniposide, and plasma concentrations were measured by a specific high-performance liquid chromatography (HPLC) assay. A two-compartment model was fitted to each subject's data.

RESULTS

The mean systemic clearance (range) for the six anticonvulsant-treated patients studied during 22 courses of therapy was 32 mL/min/m2 (range, 21 to 54 mL/min/m2), significantly higher (P less than .001) than the mean value of 13 mL/min/m2 (range, 7 to 17 mL/min/m2) for the control patients studied during 26 courses of therapy. Clearance estimates for control patients were similar to previously published values for pediatric patients.

CONCLUSION

These data indicate that the systemic clearance of teniposide is consistently increased two- to three-fold by concomitant phenobarbital or phenytoin therapy. The consequent substantial reduction in systemic exposure may reduce teniposide's efficacy.

Removal of phenytoin by plasmapheresis in a patient with thrombotic thrombocytopenia purpura

Phenytoin removal by plasmapheresis was evaluated in a 17-year-old girl with thrombotic thrombocytopenia purpura. Free and total phenytoin concentrations were measured in the patient's serum and in the plasma removed by plasmapheresis. Plasmapheresis was performed on three separate days with the removal of 4.7%, 3.3%, and 2.7% of total body stores. Free phenytoin concentration was similar in both the plasma removed by plasmapheresis and the patient's serum. Plasmapheresis did not significantly alter the serum concentration of phenytoin; dosage adjustments of phenytoin are therefore unnecessary.

Somnolence, hypotension, and metabolic acidosis following high-dose teniposide treatment in children with leukemia

This report describes an unexpected adverse effect in three children receiving teniposide at 3-5 times the conventional dosage (i.e. 200 mg/m2) plus cytarabine as part of continuation therapy for acute lymphocytic leukemia. Pharmacokinetic studies in each patient had demonstrated high teniposide clearances, and thus the increased dosage requirements were necessary to attain plasma concentrations similar to those expected for patients with average drug clearance. At 3-4 h after the beginning of the 4-h simultaneous infusions of teniposide and cytarabine, these patients experienced somnolence, hypotension, and metabolic acidosis. The adverse events were associated with elevated teniposide plasma concentrations during the infusions compared with those in patients receiving similar doses without toxicity, and clinically significant ethanol concentrations, presumably from the teniposide formulation. Blood concentrations of cremophor and histamine, which are also constituents of the teniposide formulation, were not measured. In addition, concomitant therapy with antiemetic agents in patients who may have been mildly volume-depleted due to emesis may also play a contributory role. Prolonging the infusion time for patients receiving teniposide doses above 500 mg/m2 will avoid excessive teniposide and ethanol plasma concentrations and minimize the risk of this potentially serious side effect.

Vancomycin does not enhance amikacin-induced tubular nephrotoxicity in children

A three-drug antibiotic regimen including vancomycin and amikacin has been recommended as effective treatment in clinical settings in which Gram-positive bacteremias are a serious problem. To determine if vancomycin potentiates the tubular proteinuria associated with amikacin therapy, we studied febrile, neutropenic children with leukemia who were treated with either amikacin (800 mg/m2/day) and ticarcillin-clavulanate or with vancomycin (1.2 g/m2/day), amikacin and ticarcillin. Tubular proteinuria was assessed in 14 children by monitoring the excretion of total urinary protein and two other sensitive indicators of nephrotoxicity, the renal tubular enzymes N-acetyl-beta-D-glucosaminidase and alanine aminopeptidase, in sequential 8-hour urine collections during 7 days of antimicrobial therapy. There were no significant differences between the two treatment groups in excretion of the three marker proteins when values were compared on any day of therapy or for the entire 7-day course. Nor did we observe any significant changes in either serum creatinine concentrations or amikacin clearance rates in the larger study group of 101 children from which these patients were drawn. Although amikacin was subclinically nephrotoxic, the addition of vancomycin to amikacin therapy did not enhance clinical or tubular nephrotoxicity in these children.

Vancomycin, ticarcillin, and amikacin compared with ticarcillin-clavulanate and amikacin in the empirical treatment of febrile, neutropenic children with cancer

We assessed two antibiotic regimens--vancomycin, ticarcillin, and amikacin, as compared with a vancomycin placebo, ticarcillin-clavulanate, and amikacin--as initial empirical therapy for febrile, neutropenic children with cancer. In a randomized, double-blind clinical trial, the planned 10-day treatment was unsuccessful in 15 percent of the vancomycin, ticarcillin, and amikacin group (n = 53), as compared with 38 percent of the group receiving ticarcillin-clavulanate and amikacin (n = 48) (P = 0.010). Of 10 episodes of breakthrough bacteremia, 9 (1 fatal) occurred in patients treated with ticarcillin-clavulanate and amikacin (P = 0.006). Each of the 10 microbial isolates was a gram-positive bacterium with similar susceptibilities to vancomycin and ticarcillin-clavulanate in vitro. Both regimens were well tolerated. None of the patients had detectable renal dysfunction, but those receiving vancomycin, ticarcillin, and amikacin were more likely to have twofold increases in serum hepatic-enzyme activity. Rashes consistent with the "red-man" syndrome occurred in three patients upon the infusion of vancomycin and in three others who received a placebo. We conclude that the combination of vancomycin, ticarcillin, and amikacin is more effective than ticarcillin-clavulanate and amikacin as empirical antibiotic therapy in clinical settings in which gram-positive bacteremias are a serious problem.

Monitoring serum aminoglycoside concentrations in children with amphotericin B nephrotoxicity

We prospectively studied the effect of amphotericin B therapy on aminoglycoside clearance in 20 consecutive children during the remission-induction phase of chemotherapy for acute myelocytic leukemia. Increases (greater than 50%) in the half-life for aminoglycoside excretion were not associated with antileukemic or aminoglycoside therapy alone but occurred in 12 of 17 children when amphotericin B was added to the antimicrobial regimen. Seven children had impaired aminoglycoside clearance without increases (greater than 50%) in serum creatinine; hence the resulting adjustments in aminoglycoside dosage would not have been made had we relied solely on serial measurements of serum creatinine. Evidence for increased excretion of the renal enzymes N-acetyl-beta-D-glucosaminidase and alanine aminopeptidase during amphotericin B therapy suggested that damage to proximal tubular cells may contribute to the renal impairment that has been associated with this drug. Our findings underscore the value of monitoring serum aminoglycoside concentrations in children being treated with amphotericin B.