Gerard R. Barber

Linezolid interaction with serotonin reuptake inhibitors: report of two cases and incidence assessment

Abstract Background: Prompted by the advent of potentially life-threatening neuromuscular symptoms following initiation of linezolid therapy in two patients receiving treatment with a serotonin reuptake inhibitor antidepressant, an evaluation was conducted to determine the incidence and characteristics of symptomatic serotonin toxicity among hospitalized patients receiving combined treatment with these medications. Methods: Patients admitted between January 1, 2006 and August 30, 2008 who received linezolid concurrently with citalopram or escitalopram were identified and their medical records were examined. Patients were judged to have serotonin toxicity if their records contained documentation of clinical evidence adequate to fulfill requisites of the Hunter Serotonin Toxicity Criteria. Severity of serotonin-related symptoms was graded according to previously established criteria. Results: During the period of observation, 24 patients received concurrent treatment with linezolid and citalopram or escitalopram. Of these, one patient (4%) treated with citalopram met evidentiary requirements for diagnosis of serotonin toxicity. The severity of symptoms in this patient was graded as mild. No evidence of serious harm related to a possible drug interaction was identified. Conclusions: Severe symptoms associated with serotonin toxicity were shown to be uncommon in patients receiving linezolid and selected serotonin reuptake inhibitors. Nonetheless, serious interaction-related toxicity has been observed at our institution and reported in detail by others. Accordingly, concurrent use of these medications is categorized as contraindicated. Alternative antimicrobial therapy should be instituted in most cases. If no suitable alternative is available, recipient patients should be hospitalized for expectant observation and rigorous monitoring.

Statins and daptomycin: safety assessment of concurrent use and evaluation of drug interaction liability.

Abstract Background: Acute muscle injury and potentially fatal rhabdomyolysis may occur with use of statins and certain interacting medications. This investigation assessed risk for myopathy in patients receiving treatment with a statin in combination with daptomycin, a medication also associated with muscle injury. Methods: Patients hospitalized from July 1, 2005, through June 30, 2010, who received simvastatin or rosuvastatin concurrently with daptomycin were identified and their medical records were examined. Patients were judged to have treatment-related muscle injury if their records contained evidence of myalgia with or without weakness and secondarily impaired mobility together with elevated creatine kinase (CK) levels. These assessments were compared with similar data from hospitalized patients who received a statin alone. Results: A total of 52 patients received 66 courses of concurrent treatment with simvastatin or rosuvastatin and daptomycin. Of these, no patient (0%) met evidentiary requirements for diagnosis of myopathy or related complications. No patient (0%) developed muscle pain or discomfort and none developed markedly elevated CK levels. The incidence of asymptomatic elevations of CK in these simvastatin or rosuvastatin plus daptomycin recipients (9%) was statistically indistinguishable from the incidence of CK elevations found in a cohort of 105 inpatients who received simvastatin or rosuvastatin alone (21%; p=0.135). Conclusions: In patients receiving treatment with simvastatin or rosuvastatin and daptomycin, no symptoms or objective evidence of muscle injury attributable to a drug interaction were identified. These findings are consistent with data indicating that the myopathic effects of statins and daptomycin are incited by disparate and perhaps unique pharmacological mechanisms. Risk of muscle injury therefore appears to be no greater when a statin is administered with daptomycin than when either medication is used alone.

Perioperative blood loss in total hip and knee arthroplasty: Outcomes associated with intravenous tranexamic acid use in an academic medical center

Objectives: Clinical trials have reported decreased blood loss with the use of tranexamic acid during joint reconstruction. The purpose of this study was to assess the individual practice implications of tranexamic acid use in joint replacement surgery. Methods: Health records of adults undergoing total knee arthroplasty and total hip arthroplasty over a 12-month period were retrospectively reviewed. The treatment group comprised patients who received intravenous tranexamic acid perioperatively. The control group comprised patients who did not receive tranexamic acid. Results: Patients in the treatment group (n = 64) and the control group (n = 99) were well matched for demographics, orthopedic diagnosis, and comorbidities. In-hospital postsurgical mean decreases in hemoglobin concentrations were −4.05 g/dL and −4.94 g/dL in the treatment and control groups, respectively (p < 0.001). Postsurgical mean decreases in hematocrit levels were −11.2% and −14.2% in the treatment and control groups, respectively (p < 0.001). Three patients in the treatment group (5%) and 21 patients in the control group (21%) received red blood cell transfusions (p = 0.006). As compared to control, the relative risk of transfusion in the treatment group was 0.23 (95% confidence interval = 0.07–0.76) and the number needed to treat to avoid one transfusion was 7.0 (95% confidence interval = 3.8–14.4). No evidence of thromboembolism or other serious complications were observed in either group. Conclusions: In patients undergoing joint replacement surgery, perioperative administration of tranexamic acid was associated with diminished blood loss and lesser resource utilization.

Electronic Inventory Systems and Barcode Technology: Impact on Pharmacy Technical Accuracy and Error Liability

PURPOSE To measure the effects associated with sequential implementation of electronic medication storage and inventory systems and product verification devices on pharmacy technical accuracy and rates of potential medication dispensing errors in an academic medical center. METHODS During four 28-day periods of observation, pharmacists recorded all technical errors identified at the final visual check of pharmaceuticals prior to dispensing. Technical filling errors involving deviations from order-specific selection of product, dosage form, strength, or quantity were documented when dispensing medications using (a) a conventional unit dose (UD) drug distribution system, (b) an electronic storage and inventory system utilizing automated dispensing cabinets (ADCs) within the pharmacy, (c) ADCs combined with barcode (BC) verification, and (d) ADCs and BC verification utilized with changes in product labeling and individualized personnel training in systems application. RESULTS Using a conventional UD system, the overall incidence of technical error was 0.157% (24/15,271). Following implementation of ADCs, the comparative overall incidence of technical error was 0.135% (10/7,379; P = .841). Following implementation of BC scanning, the comparative overall incidence of technical error was 0.137% (27/19,708; P = .729). Subsequent changes in product labeling and intensified staff training in the use of BC systems was associated with a decrease in the rate of technical error to 0.050% (13/26,200; P = .002). CONCLUSIONS Pharmacy ADCs and BC systems provide complementary effects that improve technical accuracy and reduce the incidence of potential medication dispensing errors if this technology is used with comprehensive personnel training.

Implementing standardized intravenous antibiotic desensitizations among hospital inpatients.

PURPOSE Patient safety improvements and increased efficiencies achieved through the establishment of standardized protocols and order sets for selected antibiotic desensitization procedures are described. SUMMARY Errors in the ordering and administration of antimicrobial desensitization regimens can result in life-threatening complications. To enhance patient safety, the University of Colorado Hospital pharmacy department worked with allergy and immunology physicians (AIPs) to implement standardized desensitization protocols to reduce the potential for confusion surrounding the prescribing and administration of these complex regimens to acutely ill populations such as patients with cystic fibrosis, as many as 30% of whom develop one or more antimicrobial allergies. Nine i.v. antibiotics were identified as suitable for the standardization initiative; based on AIP experience and published guidelines, therapeutic doses of each targeted medication were determined. For each of the nine drugs, the interdisciplinary team developed an instruction sheet on preparing stock concentrations and compounding sequential doses for desensitization, with a corresponding preprinted order set detailing infusion procedures, monitoring requirements, guidance on the use of rescue medications and other steps for managing adverse reactions, and patient safeguards. Initial experience with the standardized protocols indicated that relative to previous practices (i.e., physician submission of handwritten patient-specific orders, with pharmacist calculation of required dilutions case by case), the standardization initiative (1) reduced the potential for errors, (2) sharply reduced order-entry and product preparation times, and (3) helped achieve antimicrobial stewardship goals. CONCLUSION Standardized antimicrobial desensitization protocols helped to optimize patient care and antimicrobial stewardship while enabling more efficient use of pharmacy and AIP resources and fostering enhanced pharmacist-physician collaboration.

Managing the Intravenous Calcium Shortage: Evaluation of Calcium Chloride Stability in 0.9% Sodium Chloride and Dextrose 5% Water Polyvinyl Chloride Bags

Background Intravenous calcium chloride (CaCl) is commonly used by inpatient practitioners for a myriad of indications from electrolyte abnormalities to advanced cardiac life support. Currently, a paucity of data is available regarding the stability of CaCl after preparation of intravenous admixtures. Purpose This study evaluated the physical and chemical stability of CaCl 10% diluted in 0.9% sodium chloride or dextrose 5% water polyvinyl chloride bags. Method CaCl 10% solution (1000 mg) was diluted with 0.9% sodium chloride or dextrose 5% water 100 mL for injection to a final concentration of 10 mg/mL. CaCl 10% solution (2000 mg) was diluted with 0.9% sodium chloride or dextrose 5% water 150 mL for injection to a final concentration of 13.3 mg/mL. Each of the preparations were stored at room temperature (23–25°C) and exposed to fluorescent light. Samples of each preparation were analyzed on days 0, 2, 3, 5, and 7. Sterility and physical stability were assessed. Chemical stability of CaCl was evaluated by indirect potentiometry. Results CaCl 10 mg/mL and 13.3 mg/mL solutions in polyvinyl chloride bags were physically stable during the entire 7-day study period. CaCl retained >90% of the original concentration at 7 days after preparation in 0.9% sodium chloride and dextrose 5% water. Conclusion CaCl diluted to 10 mg/mL or 13.3 mg/mL with 0.9% sodium chloride or dextrose 5% water for injection is both physically and chemically stable for a period of 7 days with ≤10% degradation under conditions of room temperature with fluorescent lighting.

Compliance With Hospital Medication Management Standards for Safety and Efficacy Information

The Joint Commission on Accreditation of Healthcare Organizations (TJC) requires US hospitals to manage all aspects of medication use throughout the institution. Within its medication management (MM) standards, TJC lists explicit expectations for establishment of policies governing the procurement, storage, labeling, administration, and monitoring of medications. Although conventional hospital pharmacy operational requirements are well described in TJC standards, drug information requirements are less clear. TJC standards for drug information in hospitals are limited to MM 02.01.01 (formerly MM 2.10) titled ‘‘The hospital selects and procures medications.’’ Within this standard, Element of Performance (EP) 9 states ‘‘Medications designated as available for dispensing or administration are reviewed at least annually based on emerging safety and efficacy information.’’ A similar statement is also found in the Centers for Medicare and Medicaid Conditions for Participation No. 482.25. This report describes our interpretation of the intent of this standard and subsequent efforts by drug information specialists at our hospital to comply with its requirements.

Both sides of the bed rail

It’s been said of life that since we’re just passing through, we should make the most of it. So, it’s especially peculiar that health care professionals don’t embrace this little ditty with a veritable stranglehold. It’s not that “white coats” are any more astute than anyone else, it