A preliminary examination of over-the-counter medication misuse rates in older adults

BACKGROUND

Older adults are the largest consumers of over the counter (OTC) medications. Of the older adults who are at risk of a major adverse drug event, more than 50% of these events involve an OTC medication.

OBJECTIVE

To explore how older adults select and hypothetically use OTC medications and if the selected medications would be considered safe for use.

METHODS

Walking interviews were conducted with 20 community-dwelling older adults in a community pharmacy. Each participant selected an OTC medication for a hypothetical pain and sleep scenario. Data were analyzed for four types of misuse: drug-drug interaction, drug-disease interaction, drug-age interaction, and excess usage.

RESULTS

At least one instance of potential misuse was found in 95% of participants. For sleep medications, drug-drug interactions and drug-age interactions were more common, affecting 50% and 65% of participants respectively. The most common type of misuse noted in the pain products selected was that of drug-drug interaction, with a total of 39 occurrences, affecting 60% of the participants.

CONCLUSIONS

OTC misuse is common among older adults, and it is important for older adults to seek out resources, such as a pharmacist, to help them make safe OTC decisions.

Barriers and facilitators to recovering from e-prescribing errors in community pharmacies

OBJECTIVE

To explore barriers and facilitators to recovery from e-prescribing errors in community pharmacies and to explore practical solutions for work system redesign to ensure successful recovery from errors.

DESIGN

Cross-sectional qualitative design using direct observations, interviews, and focus groups.

SETTING

Five community pharmacies in Wisconsin.

PARTICIPANTS

13 pharmacists and 14 pharmacy technicians.

INTERVENTIONS

Observational field notes and transcribed interviews and focus groups were subjected to thematic analysis guided by the Systems Engineering Initiative for Patient Safety (SEIPS) work system and patient safety model.

MAIN OUTCOME MEASURES

Barriers and facilitators to recovering from e-prescription errors in community pharmacies.

RESULTS

Organizational factors, such as communication, training, teamwork, and staffing levels, play an important role in recovering from e-prescription errors. Other factors that could positively or negatively affect recovery of e-prescription errors include level of experience, knowledge of the pharmacy personnel, availability or usability of tools and technology, interruptions and time pressure when performing tasks, and noise in the physical environment.

CONCLUSION

The SEIPS model sheds light on key factors that may influence recovery from e-prescribing errors in pharmacies, including the environment, teamwork, communication, technology, tasks, and other organizational variables. To be successful in recovering from e-prescribing errors, pharmacies must provide the appropriate working conditions that support recovery from errors.

The myth of standardized workflow in primary care

OBJECTIVE

Primary care efficiency and quality are essential for the nation's health. The demands on primary care physicians (PCPs) are increasing as healthcare becomes more complex. A more complete understanding of PCP workflow variation is needed to guide future healthcare redesigns.

METHODS

This analysis evaluates workflow variation in terms of the sequence of tasks performed during patient visits. Two patient visits from 10 PCPs from 10 different United States Midwestern primary care clinics were analyzed to determine physician workflow. Tasks and the progressive sequence of those tasks were observed, documented, and coded by task category using a PCP task list. Variations in the sequence and prevalence of tasks at each stage of the primary care visit were assessed considering the physician, the patient, the visit's progression, and the presence of an electronic health record (EHR) at the clinic.

RESULTS

PCP workflow during patient visits varies significantly, even for an individual physician, with no single or even common workflow pattern being present. The prevalence of specific tasks shifts significantly as primary care visits progress to their conclusion but, notably, PCPs collect patient information throughout the visit.

DISCUSSION

PCP workflows were unpredictable during face-to-face patient visits. Workflow emerges as the result of a "dance" between physician and patient as their separate agendas are addressed, a side effect of patient-centered practice.

CONCLUSIONS

Future healthcare redesigns should support a wide variety of task sequences to deliver high-quality primary care. The development of tools such as electronic health records must be based on the realities of primary care visits if they are to successfully support a PCP's mental and physical work, resulting in effective, safe, and efficient primary care.

Application of a Systems Pharmacology-Based Placebo Population Model to Analyze Long-Term Data of Postmenopausal Osteoporosis

Osteoporosis is a progressive bone disease characterized by decreased bone mass resulting in increased fracture risk. The objective of this investigation was to test whether a recently developed disease systems analysis model for osteoporosis could describe disease progression in a placebo-treated population from the Early Postmenopausal Intervention Cohort (EPIC) study. First, we qualified the model using a subset from the placebo arm of the EPIC study of 222 women who had similar demographic characteristics as the 149 women from the placebo arm of the original population. Second, we applied the model to all 470 women. Bone mineral density (BMD) dynamics were changed to an indirect response model to describe lumbar spine and total hip BMD in this second population. This updated disease systems analysis placebo model describes the dynamics of all biomarkers in the corresponding datasets to a very good approximation; a good description of an individual placebo response will be valuable for evaluating treatments for osteoporosis.

Psychometric properties of the AHRQ Community Pharmacy Survey on Patient Safety Culture: a factor analysis

BACKGROUND

The U.S. Agency for Healthcare Research and Quality (AHRQ) developed a hospital patient safety culture survey in 2004 and has adapted this survey to other healthcare settings, such as nursing homes and medical offices, and most recently, community pharmacies. However, it is unknown whether safety culture dimensions developed for hospitals can be transferred to community pharmacies. The aim of this study was to assess the psychometric properties of the Community Pharmacy Survey on Patient Safety Culture.

METHOD

The survey was administered to 543 community pharmacists in Wisconsin, USA. Confirmatory factor analysis was used to assess the fit of our data with the proposed AHRQ model. Exploratory factor analysis was used to determine the underlying factor structure. Internal consistency reliabilities were calculated.

RESULTS

A total of 433 usable surveys were returned (response rate 80%). Results from the confirmatory factor analysis showed inadequate model fit for the original 36 item, 11-factor structure. Exploratory factor analysis showed that a modified 27-item, four-factor structure better reflected the underlying safety culture dimensions in community pharmacies. The communication openness factor, with three items, dropped in its entirety while six items dropped from multiple factors. The remaining 27 items redistributed to form the four-factor structure: safety-related communication, staff training and work environment, organisational response to safety events, and staffing, work pressure and pace. Cronbach's α of 0.95 suggested good internal consistency.

CONCLUSIONS

Our findings suggest that validation studies need to be conducted before applying safety dimensions from other healthcare settings into community pharmacies.

(De)synchronization of advanced visual information and ball flight characteristics constrains emergent information-movement couplings during one-handed catching

Advance visual information of a projection action and ball flight information is important for organizing dynamic interceptive actions like catching. However, how the central nervous system (CNS) manages the relationship between advance visual information and emerging ball flight information in regulating behavior is less well understood. Here, we sought to examine the extent that advance visual information to the CNS constrains regulation of catching actions by synchronizing and desynchronizing its relationship with ball trajectory characteristics. Novel technology was used to present video footage of an actor throwing a ball at three different speeds, integrated with information from a real ball projected by a machine set to the three speeds. The technology enabled three synchronized and six desynchronized conditions between advance visual information and subsequent ball flight trajectories. Catching performance, kinematic data from the catching hand and gaze behaviors were recorded. Findings revealed that desynchronization of video images of ball projection shaped emergent catching behaviors. Footage of slower throws, paired with faster ball projection speeds, caused catching performance decrements. Timing in early phases of action was organized by the CNS to match the advance visual information presented. In later phases, like the grasp, ball flight information constraints adapted and regulated behaviors. Gaze behaviors showed increased ball projection speed resulted in participants tracking the ball for a smaller percentage of ball flight. Findings highlighted the role of the two visual systems in perception and action, implicating the importance of coupling advanced visual information and ball flight to regulate emergent movement coordination tendencies during interceptive behaviors.

How do community pharmacies recover from e-prescription errors?

BACKGROUND

The use of e-prescribing is increasing annually, with over 788 million e-prescriptions received in US pharmacies in 2012. Approximately 9% of e-prescriptions have medication errors.

OBJECTIVE

To describe the process used by community pharmacy staff to detect, explain, and correct e-prescription errors.

METHODS

The error recovery conceptual framework was employed for data collection and analysis. 13 pharmacists and 14 technicians from five community pharmacies in Wisconsin participated in the study. A combination of data collection methods were utilized, including direct observations, interviews, and focus groups. The transcription and content analysis of recordings were guided by the three-step error recovery model.

RESULTS

Most of the e-prescription errors were detected during the entering of information into the pharmacy system. These errors were detected by both pharmacists and technicians using a variety of strategies which included: (1) performing double checks of e-prescription information; (2) printing the e-prescription to paper and confirming the information on the computer screen with information from the paper printout; and (3) using colored pens to highlight important information. Strategies used for explaining errors included: (1) careful review of patient's medication history; (2) pharmacist consultation with patients; (3) consultation with another pharmacy team member; and (4) use of online resources. In order to correct e-prescription errors, participants made educated guesses of the prescriber's intent or contacted the prescriber via telephone or fax. When e-prescription errors were encountered in the community pharmacies, the primary goal of participants was to get the order right for patients by verifying the prescriber's intent.

CONCLUSION

Pharmacists and technicians play an important role in preventing e-prescription errors through the detection of errors and the verification of prescribers' intent. Future studies are needed to examine factors that facilitate or hinder recovery from e-prescription errors.

Implementation of quantitative and systems pharmacology in large pharma

Quantitative and systems pharmacology concepts and tools are the foundation of the model-informed drug development paradigm at Merck for integrating knowledge, enabling decisions, and enhancing submissions. Rigorous prioritization of modeling and simulation activities has enabled key drug development decisions and led to a high return on investment through significant cost avoidance. Critical factors for the successful implementation, examples on impact on decision making with associated return of investment, and drivers for continued success are discussed.

Facilitating collaboration between pharmacists and physicians using an iterative interview process

OBJECTIVE To elicit and describe mutually agreed upon common problems and subsequent solutions resulting from a facilitated face-to-face meeting between pharmacists and physicians. DESIGN Descriptive, exploratory, nonexperimental study. SETTING Wisconsin from October to December 2011. PARTICIPANTS Physicians and community pharmacists. INTERVENTION Face-to-face semistructured interviews with pharmacists and physicians from the same community, informed by previous individual interviews. MAIN OUTCOME MEASURES Methods to enhance collaboration and barriers to implementing collaboration between pharmacists and physicians. RESULTS Physicians and pharmacists generated ideas in which collaboration could improve patient care, including controlled substance monitoring, medication adherence, collaborative practice agreements for point-of-service issues, and a mechanism for urgent communication. Methods on how to collaborate on these issues also were discussed. CONCLUSION Bringing physicians and pharmacists together for a face-to-face interaction that was informed by information gained in previous individual interviews successfully stimulated conversation on ways in which each profession could help the other provide optimal patient care. This interaction appeared to dispel assumptions and build trust. The results of this project may provide pharmacists with the confidence to reach out to their physician colleagues.

Using a conflict conceptual framework to describe challenges to coordinated patient care from the physicians' and pharmacists' perspective

BACKGROUND

In an effort to increase cost-effectiveness of health care and reduce overall costs, patient-centered medical homes have been proposed to spur fundamental changes in the way primary care is delivered. One of the chief principles that describe a patient-centered medical home is that care is organized across all elements of the broader health care system, including community pharmacies.

OBJECTIVES

To identify and describe challenges derived from a conflict management framework to a physician-pharmacist approach to coordinating patient care.

METHODS

A descriptive, exploratory, non-experimental study was conducted in Wisconsin (U.S. State) from June to December, 2011. Data were collected through two rounds of face-to-face interviews with physicians and community pharmacists. The first round involved one-on-one interviews with pharmacists and physicians. The second round brought pharmacist-physician dyads together in an open-ended interview exploring issues raised in the first round. Content analysis was guided by a conflict management conceptual framework using NVivo 10 qualitative software.

RESULTS

A total of four major themes emerged from the conflict analysis of interviews that illustrate challenges to coordinated patient care: Scarce resources, technology design and usability, insurance constraints, and laws and policy governing patient care. The study findings indicate that both groups of health care professionals work within an environment of conflict and have to negotiate the challenges and strains that exist in the current health care system. Their need to work together, or interdependence, is primarily challenged by scarce resources and external interference.

CONCLUSIONS

Efforts to coordinate patient care through teams of inter-professional health care providers will be more successful if they acknowledge the inherent conflict that exists. Efforts should be made to provide an infrastructure for interdependence and to support interpersonal communication.

The prescription handoff in community pharmacy: a study of its form and function

OBJECTIVE

To describe and explore handoffs in community pharmacy.

DESIGN

Descriptive, exploratory, nonexperimental study.

SETTING

Wisconsin, August to October 2008.

PARTICIPANTS

Community pharmacists.

INTERVENTION

Brief, face-to-face, semistructured interviews.

MAIN OUTCOME MEASURE

Information on characteristics of handoffs, including the reasons for handoffs, what kind of information is shared during handoffs, and how information is shared.

RESULTS

The overarching reasons handoffs are done in community pharmacy are because some of the necessary information is confusing, contradictory, or absent, and/or the drug product is not in stock. Handoff information typically consists of a description of the problem, the current status of the problem, what information is still needed, and future steps to resolve the problem. Handoffs can occur synchronously during a shift change or asynchronously when one pharmacist signs out at the end of the day and another pharmacist opens the pharmacy the next morning. While synchronous handoffs are generally verbal in nature, asynchronous handoff information is primarily conveyed via paper or electronic notes on the dispensing computer system.

CONCLUSION

Our results suggest that handoffs do take place in community pharmacies and that the process is unstructured and variable. Future studies should fully characterize this process and explore possible strategies for improvement.

Safeguarding older adults from inappropriate over-the-counter medications: the role of community pharmacists

PURPOSE OF THE STUDY

To elicit the thought process or mental model that community pharmacists use when making recommendations on over-the-counter (OTC) medications to older adults and to elicit the current practices of community pharmacists in providing information, advice, and counseling to older adults about potentially inappropriate OTC medications.

DESIGN AND METHODS

Three separate focus groups with pharmacists were conducted with 5 to 8 pharmacists per group. A vignette about an elderly woman seeking an OTC sleep aid was used to elicit information that pharmacists seek to establish when making a recommendation. Focus groups were recorded, transcribed verbatim, and analyzed for themes using the initial and focused coding methods of grounded theory.

RESULTS

Community pharmacists' mental models were characterized by 2 similarities: a similarity in what community pharmacists seek to establish about patients and a similarity in when community pharmacists seek to establish it--the sequence in which they try to learn key details about patients. It was identified that pharmacists gather specific information about the patient's medication profile, health conditions, characteristics of the problem, and past treatments in order to make a recommendation. Community pharmacists recommended behavioral modifications and seeing their physician prior to recommending an OTC sleep aid, primarily due to medication safety concerns.

IMPLICATIONS

Pharmacists can play a key role in assisting older adults to select and use OTC medications.

Rifampin's acute inhibitory and chronic inductive drug interactions: experimental and model-based approaches to drug-drug interaction trial design

We studied the time course for the reversal of rifampin's effect on the pharmacokinetics of oral midazolam (a cytochrome P450 (CYP) 3A4 substrate) and digoxin (a P-glycoprotein (P-gp) substrate). Rifampin increased midazolam metabolism, greatly reducing the area under the concentration-time curve (AUC(0-∞)). The midazolam AUC(0-∞) returned to baseline with a half-life of ~8 days. Rifampin's effect on the AUC(0-3 h) of digoxin was biphasic: the AUC(0-3 h) increased with concomitant dosing of the two drugs but decreased when digoxin was administered after rifampin. Digoxin was found to be a weak substrate of organic anion-transporting polypeptide (OATP) 1B3 in transfected cells. Although the drug was transported into isolated hepatocytes, it is not likely that this transport was through OATP1B3 because the transport was not inhibited by rifampin. However, rifampin did inhibit the P-gp-mediated transport of digoxin with a half-maximal inhibitory concentration (IC(50)) below anticipated gut lumen concentrations, suggesting that rifampin inhibits digoxin efflux from the enterocyte to the intestinal lumen. Pharmacokinetic modeling suggested that the effects on digoxin are consistent with a combination of inhibitory and inductive effects on gut P-gp. These results suggest modifications to drug-drug interaction (DDI) trial designs.

Pharmacokinetics of raltegravir in individuals with UGT1A1 polymorphisms

Raltegravir is a human immunodeficiency virus-1 (HIV-1) integrase strand transfer inhibitor metabolized by glucuronidation via UDP-glucuronosyltransferase 1A1 (UGT1A1). In this study, 30 subjects with a UGT1A1*28/*28 genotype (associated with decreased activity of UGT1A1) and 27 UGT1A1*1/*1 control subjects (matched by race, age, gender, and body mass index) received a single 400-mg dose of raltegravir after fasting. No serious adverse experiences were reported, and there were no discontinuations due to adverse experiences. The geometric mean ratio (GMR) (UGT1A1*28/*28 to UGT1A1*1/*1) and 90% confidence interval (CI) were 1.41 (0.96, 2.09) for raltegravir area under the concentration-time curve (AUC(0-infinity)), 1.40 (0.86, 2.28) for maximum plasma concentration (C(max)), and 1.91 (1.43, 2.55) for concentration at the 12-h time point (C(12 h)). No clinically important differences in time to maximum concentration (T(max)) or half-life were observed. Plasma concentrations of raltegravir are modestly higher in individuals with the UGT1A1*28/*28 genotype than in those with the UGT1A1*1/*1 genotype. This increase is not clinically significant, and therefore no dose adjustment of raltegravir is required for individuals with the UGT1A1*28/*28 genotype.

Safety, Tolerability, and Pharmacokinetics of Raltegravir After Single and Multiple Doses in Healthy Subjects

Raltegravir is a novel human immunodeficiency virus-1 integrase inhibitor with potent in vitro activity (95% inhibitory concentration (IC95)=33 nM in 50% human serum). Three double-blind, randomized, placebo-controlled, pharmacokinetic, safety, and tolerability studies were conducted: (1) single-dose escalation study (10-1,600 mg), (2) multiple-dose escalation study (100-800 mg q12 h x 10 days), and (3) single-dose female study (400 mg). Raltegravir was rapidly absorbed with a terminal half-life (t1/2) approximately 7-12 h. Approximately 7-14% of raltegravir was excreted unchanged in urine. Area under the curve (AUC)(0-infinity) was similar between male and female subjects. After multiple-dose administration, steady state was achieved within 2 days; there was little to modest accumulation of raltegravir. Trough levels were >33 nM for dose levels of 100 mg and greater. Raltegravir is generally well tolerated at doses of up to 1,600 mg/day given for up to 10 days and exhibits a pharmacokinetic profile supportive of twice-daily dosing with multiple doses of 100 mg and greater achieving trough levels >33 nM.

Mobility resolution and mass analysis of ions from ammonia and hydrazine complexes with ketones formed in air at ambient pressure

Protonated ammonia and hydrazines (MH(+)) form complexes with ketones and the differences in masses and mobilities of the resulting ions, MH(+)(ketone)(n), are sufficient for separation in an ion mobility spectrometer at ambient pressure. The highest mass ion for any of the protonated molecules is obtained when the ketone is present at elevated concentrations in the supporting atmosphere of both the source and drift regions of the spectrometer so that an ion maintains a discrete composition and mobility. The sizes of the ion-molecule complexes were found to depend on the number of H atoms on the protonated nitrogen atom--four for ammonia, three for hydrazine, two for monomethylhydrazine, and one for 1,1-dimethylhydrazine, and the drift times of these ions were proportional to the size of the ion-molecule complex. Unexpected side products, including protonated hydrazones and azines, and associated ketone clusters, were isolated to a single drift tube containing ceramic parts and could not, from CID studies, be attributed to gas-phase ion chemistry. These findings illustrate that mobility resolution of ions in IMS and IMS/MS experiments can be enhanced through chemical modification of the supporting gas atmosphere without changes in the core ion.

Characterization of nelfinavir binding to plasma proteins and the lack of drug displacement interactions

OBJECTIVES

To determine the characteristics of the binding of nelfinavir and active M8 to alpha1-acid glycoprotein (AAG) and human serum albumin (HSA), and to examine the displacement effects of drugs binding extensively to AAG (ritonavir and saquinavir) or to HSA (salicylic acid and valproic acid).

METHODS

Free drugs were separated by equilibrium dialysis after incubation with human plasma or purified plasma proteins and after co-incubation with potential displacers. Association constants were estimated from double-reciprocal plots of the data.

RESULTS

Nelfinavir and M8 free fractions [fractions of unbound drug (fus)] were 0.42+/-0.08% (mean+/-standard deviation) and 0.64+/-0.07%, respectively. For the two analytes, respectively, association constants were 7.25 x 10(7)/m and 3.33 x 10(7)/m for AAG and 1.11 x 10(6)/m and 7.92 x 10(5)/m for HSA. Nelfinavir fu in an AAG solution was significantly (P < 0.01) increased by the addition of ritonavir or saquinavir, whereas it was unaltered by addition of these drugs to whole plasma. Similarly, fu in an HSA solution was significantly increased (P < 0.01) by the addition of salicylic acid or valproic acid, whereas there was no difference in the free fraction in plasma.

CONCLUSIONS

The affinity of nelfinavir for human plasma proteins was higher than that of M8, and both nelfinavir and M8 showed higher affinity to AAG than to HSA. The free fraction of nelfinavir was not affected by drugs that bind extensively to AAG or albumin when these drugs were added to whole plasma in combination, suggesting a compensatory effect of alternate binding proteins.

Exaggerated respiratory chemosensitivity and association with level at 3568m in obesity

To investigate whether obesity is associated with alterations in respiratory chemosensitivity, we compared the ventilatory response to hypoxia (HVR) and hypercapnia (HCVR) in 9 obese men (BMI: 37.0+/-4.3 kg m(-2)) and 10 lean men (BMI: 25.8+/-4.8 kg m(-2)). HVR (DeltaVE, L min(-1) per DeltaSaO2, %) was measured by a progressive isocapnic hypoxia technique, and HCVR (DeltaVE/DeltaPETCO2, L min(-1)Torr(-1)) was measured by a progressive hypercapnic method. HCVR, was greater (p<0.001) in the obese men (2.68+/-0.78) than in the lean men (1.4+/-0.45) as was HVR (p<0.05) (1.26+/-0.65 versus 0.71+/-0.43, respectively). The difference (DeltaSaO2, 4.30+/-3.69 and 10.54+/-3.45 in the lean and obese men, respectively, p<0.01) between daytime (86+/-1 and 86+/-1%) and nighttime SaO2 (81+/-3 and 76+/-4%) at a simulated altitude of 3658 m was significantly (p<0.05) correlated with both HVR (r=0.51) and HCVR (r=0.48). These results suggest that chemosensitivity in mildly obese men is increased, not blunted. Furthermore, otherwise healthy, obese individuals have the potential for significant desaturation during sleep at high altitude possibly due to exaggerated sleep-disordered breathing.

Effect of moisture on the field dependence of mobility for gas-phase ions of organophosphorus compounds at atmospheric pressure with field asymmetric ion mobility spectrometry

The electric field dependence of the mobilities of gas-phase protonated monomers [(MH+(H2O)n] and proton-bound dimers [M2H+(H2O)n] of organophosphorus compounds was determined at E/N values between 0 and 140 Td at ambient pressure in air with moisture between 0.1 and 15 000 ppm. Field dependence was described as alpha (E/N) and was obtained from the measurements of compensation voltage versus field amplitude in a planar high-field asymmetric waveform ion mobility spectrometer. The alpha function for protonated monomers to 140 Td was constant from 0.1 to 10 ppm moisture in air with onset of effect at approximately 50 ppm. The value of alpha increased 2-fold from 100 to 1000 ppm at all E/N values. At moisture values between 1000 and 10 000 ppm, a 2-fold or more increase in alpha (E/N) was observed. In a model proposed here, field dependence for mobility through changes in collision cross sections is governed by the degree of solvation of the protonated molecule by neutral molecules. The process of ion declustering at high E/N values was consistent with the kinetics of ion-neutral collisional periods, and the duty cycle of the waveform applied to the drift tube. Water was the principal neutral above 50 ppm moisture in air, and nitrogen was proposed as the principal neutral below 50 ppm.

Canadian guidelines for cardiac rehabilitation and atherosclerotic heart disease prevention: a summary

Atherosclerotic heart disease (AHD) is the leading cause of death in Canadian women and men. Cardiac rehabilitation has been repeatedly shown to reduce cardiac morbidity and mortality significantly among patients with documented AHD. The Canadian Association of Cardiac Rehabilitation (CACR) has defined cardiac rehabilitation as "the enhancement and maintenance of cardiovascular health through individualized programs designed to optimize physical, psychological, social, vocational and emotional status. This process includes the facilitation and delivery of secondary prevention through heart hazard (risk factor) identification and modification in an effort to prevent disease progression and the recurrence of cardiac events". This summary presents a limited amount of background information and the majority of clinical practice recommendations contained within the previously published CACR Guidelines. These evidence-based clinical recommendations are intended as guidelines to good clinical practice rather than as standards of care. The key focus of this summary is the need for complete and targeted intervention of all heart hazards in patients at high or very high risk for, or with documented, AHD. To achieve this goal, the CACR Guidelines and this summary present risk stratification strategies designed to determine unambiguously a patient's risk of exercise-related cardiac events (short term absolute risk or disease prognosis) and their risk of recurrent AHD events (long term absolute risk from disease progression). The establishment of the short term and long term absolute AHD risks can then be used to determine heart hazard targets and the type of exercise program prescribed for patients with AHD. Despite the use of evidence-based medical practices, none of the recommendations presented in this document can replace the expert judgment of properly trained and experienced cardiac rehabilitation professionals. Health care providers must always be free to choose where and when clinical practice guidelines are applied, modified or superceded, depending on individual patient circumstances.

An LC-MS-MS method for the determination of indinavir, an HIV-1 protease inhibitor, in human plasma

A method for the determination of indinavir (IDV) (L-735 524) in human plasma by LC-MS-MS is discussed, and the validation data is presented. The analyte and internal standard are isolated from plasma by a simple acetonitrile precipitation of plasma proteins followed by centrifugation. LC-tandem mass spectrometry in positive ion, multiple reaction monitoring mode used pairs of ions at m/z of 614/421 for indinavir and 628/421 for internal standard, respectively. The calibration curve had a linear range from 3.0 to 12320 ng/ml when linear least square regression weighing 1/x was applied to the concentration versus peak area plot. The advantages of this method are the fast sample preparation, wide dynamic assay range and quick analysis taking only 5 min for each sample run. The robust nature of this assay has been further verified during routine use over several months involving multiple analysts.

Malignant schwannoma of the trigeminal nerve

SUMMARY

We present the MR imaging, CT, and clinical findings of a patient with malignant schwannoma of the trigeminal nerve. Local tumor recurrence is frequent and may be mistaken for lymphatic spread. In this report, we emphasize the natural history of this rare tumor and discuss the importance of imaging in diagnosis and surveillance.

Demyelinating diseases, leukodystrophies, and other myelin disorders

Magnetic resonance (MR) imaging recently has become the most sensitive clinical test in the detection of white matter disorders, yet neuropathologic evaluation remains the most specific. This article describes the gross and microscopic pathology of various diseases primarily or selectively affecting white matter. The discussion should provide deeper insight into the nature of white matter disease and assist in the interpretation of CT and MR images. The subject of white matter damage caused secondarily by such entities as neoplasia, trauma, infarction, or neuronal degeneration is not included.