A newly developed algorithm for switching outpatient medications to medications listed in the hospital formulary: a prospective real-word evaluation in patients admitted electively to hospital

PURPOSE

In many countries, outpatient and inpatient care are separated. During hospitalization, therefore, switching the outpatient medication to medication of the hospital formulary is required.

METHODS

We newly designed a switching algorithm in six switching steps (S0-S5) and conducted a study at Bundeswehr Hospital Hamburg (300 beds, 80% civilians). We performed (i) a medication reconciliation to obtain information on outpatient medications and (ii) a medication review to solve drug-related-problems, e.g., drug-drug interactions. We applied (iii) the algorithm to switch medications to the hospital formulary.

RESULTS

(i) We identified 475 outpatient medications (median per patient: 4; Q25/Q75 2/7) in 100 patients consecutively admitted to hospital (median age: 71; Q25/Q75: 64/80 years). Of 475 medications, the switching algorithm could not be used since product names were missing in 23.9% and strength in 1.7%. In 3.2%, switching was not required since medication was not prescribed during the hospital stay. (ii) Drug-drug interactions were identified in 31 of 79 patients with more than one medication. (iii) Of 475 medications, 18.5% were on the hospital formulary and therefore did not need to be  switched (S0), 0.2% were on a substitution-exclusion list not allowing switching (S1), 42.0% were switched to a generic medication of the hospital formulary (S2), 1.7% to a therapeutically equivalent medication (S3), 0.4% were patient-individually switched (S4), and for 8.2% a standardized/patient-individual switching was not possible (S5).

CONCLUSIONS

Despite comprehensive medication reconciliation, patient- and medication-related information for switching medications to the hospital formulary was often missing. Once all the necessary information was available, standardized switching could be easily carried out according to a newly developed switching algorithm.

[Assessing the Impact of in-Hospital Formulary Policies on the Prescription Patterns of Direct Oral Anticoagulants (DOACs)]

Prescribing direct oral anticoagulants (DOACs) with off-label dosage and administration is discouraged due to concerns about their effectiveness and safety. Consequently, our hospital pharmacist established a formulary with physicians for oral anticoagulants. Our study aimed to assess the adherence to this formulary by investigating the rate of appropriate DOAC prescribing. We included patients who were newly prescribed or continued on DOACs (dabigatran, rivaroxaban, apixaban, and edoxaban) at our hospital. We calculated the percentage of patients prescribed the correct dosage and administration according to the package insert and compared this across three time periods: pre-intervention (period A; April-September 2019), post-intervention phase 1 (period B; August 2021-January 2022), and post-intervention phase 2 (period C; November 2022-April 2023). We also examined the number of inquiries and consultation requests made by hospital pharmacists regarding DOAC dosage and administration. A total of 782 patients were surveyed (191 in period A, 263 in period B, and 328 in period C). The appropriate prescribing rates for DOACs were 79.1% in period A, 84.4% in period B, and 86.6% in period C. The proportion of cases where hospital pharmacists questioned or consulted doctors about DOAC dosage and administration was 3.7% in period A, 6.1% in period B, and 10.1% in period C. These findings indicate that active intervention by hospital pharmacists using the formulary regarding oral anticoagulant formularies may promote appropriate DOAC use.

Yinning Tablet, a hospitalized preparation of Chinese herbal formula for hyperthyroidism, ameliorates thyroid hormone-induced liver injury in rats: Regulation of mitochondria-mediated apoptotic signals

ETHNOPHARMACOLOGICAL RELEVANCE

Hyperthyroidism is closely associated with liver injury. The preliminary clinical observation suggests that Yinning Tablet, a hospitalized preparation of traditional Chinese formula for hyperthyroidism, improves not only hyperthyroidism, but also hyperthyroidism-associated liver injury.

AIM

To evaluate the effect and underlying mechanisms of Yinning Tablet on thyroid hormone-induced liver injury.

MATERIALS AND METHODS

Female rats were orally administered L-thyroxine (1 mg/kg) once daily for 60 days, and co-treated with the carefully identified Yinning Tablet extract (0.6-2.4 g/kg) during the last 30 days. Blood and liver variables were determined enzymatically, histologically, by ELISA, radioimmunoassay, Real-Time PCR or Western blot, respectively.

RESULTS

Co-treatment with the extract attenuated L-thyroxine-induced increases in serum alanine transaminase and aspartate transaminase activities, the ratio of liver weight to body weight, cytoplasmic vacuolization in hepatocytes, infiltrated inflammatory cells and confused structures in liver tissue, accompanied by attenuation of increased serum triiodo-l-thyronine concentration and hepatic deiodinase type I overexpression in rats. Importantly, Yinning Tablet suppressed L-thyroxine-triggered hepatic Bax, cleaved caspases-3, -8 and -9 protein overexpression, and Bcl-2 protein downregulation. Furthermore, the increases in cytochrome c protein expression, Ca²⁺-ATPase activity and malondialdehyde content, and decreases in activities of Na⁺/K⁺-ATPase, catalase, superoxide dismutase and glutathione peroxidase, and total antioxidant capacity in liver tissue were attenuated.

CONCLUSION

The present results suggest that Yinning Tablet ameliorates thyroid hormone-induced liver injury in rats by regulating mitochondria-mediated apoptotic signals. Our findings go insight into the pharmacological basis of the hospitalized preparation for treatment of hyperthyroidism-associated liver injury.

Impact of removal and restriction of me-too medicines in a hospital drug formulary on in- and outpatient drug prescriptions: interrupted time series design with comparison group

BACKGROUND

The study covered in- and out-of-hospital care in a region in north-western Spain. The intervention evaluated took the form of a change in the hospital drugs formulary. Before the intervention, the formulary contained four of the five low molecular weight heparins (LMWHs) marketed in Spain. The intervention consisted of withdrawing two LMWHs (bemiparin and dalteparin) from the formulary and restricting the use of another (tinzaparin), leaving only enoxaparin as an unrestricted prescription LMWH. Accordingly, the aim of this study was to evaluate the effect on in- and outpatient drug prescriptions of removing and restricting the use of several LMWHs in a hospital drugs formulary.

METHODS

We used a natural, before-after, quasi-experimental design with a control group and monthly data from January 2011 to December 2016. Based on data drawn from official Public Health Service sources, the following dependent variables were extracted: defined daily doses (DDD) per 1000 inhabitants per day (DDD/TID), DDD per 100 stays per day, and expenditure per DDD.

RESULTS

The two compounds that were removed from the formulary registered an immediate decrease at both an intra- and out-of-hospital level (66.6% and 55.6% for bemiparin and 73.0% and 92.2% for dalteparin, respectively); similarly, the compound that was restricted also registered an immediate decrease (36.1% and 9.0% at the in- and outpatient levels, respectively); in contrast, the remaining LMWH (enoxaparin) registered an immediate, significant increase at both levels (44.9% and 32.6%, respectively). The intervention led to an immediate reduction of 6.8% and a change in trend in out-of-hospital cost/DDD; it also avoided an expenditure of €477,317.1 in the 21 months following the intervention.

CONCLUSIONS

The results indicate that changes made in a hospital drugs formulary towards more efficient medications may lead to better use of pharmacotherapeutic resources in its health catchment area.

The Few. The Effective. The Cheapest. The Waste-Free Formulary

The Pacific Business Group on Health in developing a "waste-free formulary" that it hopes all purchasers could use. Such a formulary would be limited to drugs with proven clinical utility and among those, the low-cost alternatives. It is using a number of algorithms to evaluate medications.

Development and implementation of an academic cancer therapy stewardship program

OBJECTIVES

Antibiotic stewardship is an integral aspect of hospital care, limiting the potential for resistance while working to minimize waste. A similar system is needed in oncology, given the rapid proliferation of new therapies and the challenges of navigating a complicated reimbursement environment. A "cancer therapy stewardship program" has never been described in the literature. Here, we detail our efforts to design and implement such a program and share lessons learned to inform future projects.

STUDY DESIGN AND METHODS

For 1 year, a hematologist-oncologist (the "cancer therapy steward") at Mount Sinai Hospital was in charge of addressing all requests for nonformulary or off-label chemotherapeutic and supportive medications and regimens. Requests consisted of the rationale for use and supporting data from medical journal articles. This pilot initiative was focused mainly on inpatient malignant hematology.

RESULTS

Sixty-seven requests were made by 23 physicians, and all requests were ultimately approved. Requests tended to fall into 3 categories: 1) use of a single drug in a setting not approved by the FDA, 2) use of multiple drugs in novel combinations not approved by the FDA, and 3) adding novel drugs to existing FDA-approved regimens.

CONCLUSIONS

Our cancer therapy stewardship program yielded many useful insights into how our physicians face challenging clinical situations. It also helped to improve overall clinical quality and patient care by emphasizing the importance of value-based care and evidence-based medicine. Expanding this program will likely lead to many interesting experiments aimed at improving medical education and research, patient safety outcomes, and clinical quality.

How drug life-cycle management patent strategies may impact formulary management

Drug manufacturers may employ various life-cycle management patent strategies, which may impact managed care decision making regarding formulary planning and management strategies when single-source, branded oral pharmaceutical products move to generic status. Passage of the Hatch-Waxman Act enabled more rapid access to generic medications through the abbreviated new drug application process. Patent expirations of small-molecule medications and approvals of generic versions have led to substantial cost savings for health plans, government programs, insurers, pharmacy benefits managers, and their customers. However, considering that the cost of developing a single medication is estimated at $2.6 billion (2013 dollars), pharmaceutical patent protection enables companies to recoup investments, creating an incentive for innovation. Under current law, patent protection holds for 20 years from time of patent filing, although much of this time is spent in product development and regulatory review, leaving an effective remaining patent life of 7 to 10 years at the time of approval. To extend the product life cycle, drug manufacturers may develop variations of originator products and file for patents on isomers, metabolites, prodrugs, new drug formulations (eg, extended-release versions), and fixed-dose combinations. These additional patents and the complexities surrounding the timing of generic availability create challenges for managed care stakeholders attempting to gauge when generics may enter the market. An understanding of pharmaceutical patents and how intellectual property protection may be extended would benefit managed care stakeholders and help inform decisions regarding benefit management.

Leveraging hospital formularies for improved prescribing

Hospital formularies, guided by the Pharmacy and Therapeutics Committee, exist to optimize medication use by identifying and designating drugs of choice to guide rational prescribing, ultimately reducing patient risk and costs and improving patient outcomes. Guidelines and a framework exist to guide critical evaluations of medications for formulary listing; however, there may be opportunities to improve and standardize how a formulary change could be instituted in Canadian hospitals. A formulary change at an Ontario hospital revealed that there are some key challenges to the formulary change process including the importance of a robust project plan, appropriate resources, healthcare staff education, and acceptance.

Cost implications of formulary decisions on oral anticoagulants in nonvalvular atrial fibrillation

BACKGROUND

Nonvalvular atrial fibrillation (AF) is a major public health issue. The major complication of AF is an increased risk of stroke. Warfarin, long used for stroke prophylaxis in AF patients, has a narrow therapeutic window and numerous food and drug interactions necessitating regular laboratory monitoring. New oral anticoagulants (e.g., dabigatran, rivaroxaban, apixaban) may meet the need for predictable anticoagulation with fixed, unmonitored dosing.

OBJECTIVE

To review costs of monitoring, bleeding, and stroke in AF patients to analyze costs of anticoagulants for stroke prophylaxis in AF patients.

METHODS

A literature search on the costs of treating AF used PubMed/MEDLINE databases (to April 2012) focusing on studies in the United States. Key words or MeSH terms were used, such as "observational studies," "oral anticoagulants," "warfarin," "cost of bleeding," "cost of stroke," and "cost of INR monitoring."

RESULTS

The literature focused mainly on short-term, in-hospital expenditures and less on long-term care costs. Annual overall costs per patient for treating AF in the United States ranged from $18,454 to $38,270. Annual incremental costs of treating AF ranged from $8,705 to $16,311. Annual inpatient costs ranged from $7,841 to $22,582 per patient. Annual costs of anticoagulation monitoring ranged from $291 to $943 per patient. Intracranial hemorrhage and major gastrointestinal bleeding with oral anticoagulants were uncommon but expensive: 1-year costs ranged from $7,584 to $193,804. Annual direct costs of stroke in AF patients ranged from $23,143 to $37,620 (incremental cost of $7,824 to $8,232 vs. AF patients without stroke).

CONCLUSIONS

AF-associated direct costs are high and can be broken into costs of warfarin monitoring and direct costs of managing consequences of anticoagulant therapy-stroke and bleeding.

Do educational meetings and group detailing change adherence to drug formularies in hospitals? A cluster randomized controlled trial

PURPOSE

The aim of this study was to examine whether educational meetings and group detailing could increase the use of drugs from the ward lists or the drug formulary in hospitals.

METHODS

Twelve medical wards from two hospitals were randomized into three groups: control, basic and extended intervention. All wards had a ward list review before interventions. Moreover, the basic intervention consisted of an educational meeting, and the extended intervention included two group detailing sessions. The proportion of drugs used from the ward list or hospital drug formulary (HDF) was the primary outcome. Data (defined daily doses [DDDs], numbers and cost [Euros]) on drugs sold to the wards were retrieved from the two hospitals from 1 July 2011 to 31 August 2012.

BASELINE DATA

from July to September 2011, and follow-up data: from June to August 2012.

RESULTS

The proportion of formulary drugs used increased for the extended intervention group (0.04, range -0.02 to 0.09) and basic intervention group (0.03, range -0.03 to 0.09) in comparison with a decrease in the control group (-0.01, range -0.03 to -0.02). The interventions did not significantly change odds for selecting drugs from the formulary in comparison with the control group (basic intervention: OR 1.09 [95 % CI 0.81 to 1.46]; extended intervention: OR 1.00 [95 % CI 0.75 to 1.35]).

CONCLUSIONS

In this study, educational meetings and group detailing do not significantly improve adherence to ward lists or HDF. The adherence to the formularies at baseline was relatively high, which may explain why the interventions did not have a significant effect.

Assessment of new drugs in a tertiary hospital using a standardized tool

OBJECTIVE

To describe the profile of new drugs evaluated by the Pharmacy and Therapeutics committee in a tertiary hospital using a standardized tool, the Guideline for the Introduction of New Drugs in the Formulary (GINF form), as main objective.

MATERIALS AND METHODS

Retrospective observational study of drugs was assessed during 2008-2011. Variables related to the drug, the request, and the result of the evaluation were collected based on information contained in the GINF form and in the assessment reports.

RESULTS

63 of 75 assessed drugs (84%) were included in the hospital formulary. Only one drug (1%) was included without any restrictions. The rest of them were included as therapeutic equivalents (23%) or under specific recommendations (61%). Half of the drugs (6) not included had insufficient evidence of effectiveness compared with current treatments. Haematology and Medical Oncology were found to be the most active medical services in the application process. There was a high prevalence of drugs that had more than one advanced clinical trial (phase III and/or phase IV). Furthermore, 28% of assessed drugs were associated with a financial burden of more than ?10,000 per year for our hospital. Highquality information was provided by applicants to the P&T committee for drugs that were finally included. However, the relationship between the information provided to the P&T committee and its decision was not statistical significance.

CONCLUSION

The requests received were primarily related to drugs intended for parenteral use and most of them were antineoplastic drugs. The medical departments most heavily represented were Haematology and Oncology.

Deciding which drugs get onto the formulary: a value-based approach

OBJECTIVES

Hospitals, physicians, payers, and patients face economic and ethical decisions about the use of biotechnology drugs, commonly called specialty medications. These often target a small population, have data based on smaller clinical trials, are expensive, and may have questionable advantage. This is a result of how the Food and Drug Administration (FDA) approves medications, which is based only on safety and efficacy. Cancer drugs, once approved by the FDA, regardless of cost or value must be covered by Medicare. Some states have laws requiring additional coverage as well. All of this has created an unintended consequence: It has driven up costs with questionable evidence to support the medication's value, placing patients, payers, and providers in an ethical conflict. In this new era of health care transformation, health care leaders must focus on creating value to support a sustainable health system. Christiana Care Health System's Value Institute has designed a new model to evaluate specialty medications, using value as its main criterion.

METHODS

This article describes the process and outcomes using a new value model for evaluating specialty medications for a hospital formulary. It also introduces a new criterion of evaluation entitled "Societal Benefit" that provides a rating on quality- of-life issues. With measurable factors of efficacy, risk, cost, and quality-of-life concerns, our methodology provides a more balanced approach in the evaluation of specialty medications.

RESULTS

Specialty medications are the fastest growing segment of drug expense, and it is hard to understand how these medications will be sustainable under health care reforms. Unlike other countries, the United States has no national agency providing cost-effectiveness review; review occurs, if at all, at a local level. Laws governing Medicare and most private insurers' coverage of FDA-approved medication and some clinical quality standards conflict with cost-effectiveness, making this type of review difficult. Finally, because these medications affect the health system as a whole, it is a great example to begin to support health care reform.

CONCLUSIONS

Hospitals need to challenge the value of specialty medication. Although our model will continue to evolve, value is now our central consideration when selecting specialty medications to be added to the formulary. We share this experience to encourage other hospitals to design their own approach to this vital issue.

Ceftaroline fosamil use in hospitalized patients with acute bacterial skin and skin structure infections: Budget impact analysis from a hospital perspective

PURPOSE

The budgetary impact of adding ceftaroline fosamil to a hospital formulary for the treatment of acute bacterial skin and skin structure infections (ABSSSIs) was evaluated.

METHODS

A three-year hospital budget impact model was constructed with three initial treatment options for ABSSSIs: ceftaroline fosamil, vancomycin plus aztreonam, and other vancomycin-containing regimens. The target population was hospitalized adult patients with an ABSSSI. Clinical cure rates with initial treatment were assumed to be similar to those from ceftaroline fosamil clinical trials. Patients who did not respond to initial treatment were assumed to be treated successfully with second-line antimicrobial therapy. Length of stay and cost per hospital day (by success or failure with initial treatment) were estimated based on a large database from more than 100 U.S. hospitals. Other model inputs included the annual number of ABSSSI admissions, projected annual case growth rate, proportion of ABSSSI target population receiving vancomycin-containing regimen, expected proportion of ABSSSI target population to be treated with ceftaroline fosamil, drug acquisition cost, cost of antibiotic administration, and cost of vancomycin monitoring. Sensitivity analysis using 95% confidence limits of clinical cure rates was also performed.

RESULTS

The estimated total cost of care for treating a patient with an ABSSSI was $395 lower with ceftaroline fosamil ($15,087 versus $15,482) compared with vancomycin plus aztreonam and $72 lower ($15,087 versus $15,159) compared with other vancomycin-containing regimens.

CONCLUSION

Model estimates indicated that adding ceftaroline fosamil to the hospital formulary would not have a negative effect on a hospital's budget for ABSSSI treatment.

Patented drug extension strategies on healthcare spending: a cost-evaluation analysis

BACKGROUND

Drug manufacturers have developed "evergreening" strategies to compete with generic medication after patent termination. These include marketing of slightly modified follow-on drugs. We aimed to estimate the financial impact of these drugs on overall healthcare costs and also to examine the impact of listing these drugs in hospital restrictive drug formularies (RDFs) on the healthcare system as a whole ("spillover effect").

METHODS AND FINDINGS

We used hospital and community pharmacy invoice office data in the Swiss canton of Geneva to calculate utilisation of eight follow-on drugs in defined daily doses between 2000 and 2008. "Extra costs" were calculated for three different scenarios assuming replacement with the corresponding generic equivalent for prescriptions of (1) all brand (i.e., initially patented) drugs, (2) all follow-on drugs, or (3) brand and follow-on drugs. To examine the financial spillover effect we calculated a monthly follow-on drug market share in defined daily doses for medications prescribed by hospital physicians but dispensed in community pharmacies, in comparison to drugs prescribed by non-hospital physicians in the community. Estimated "extra costs" over the study period were €15.9 (95% CI 15.5; 16.2) million for scenario 1, €14.4 (95% CI 14.1; 14.7) million for scenario 2, and €30.3 (95% CI 29.8; 30.8) million for scenario 3. The impact of strictly switching all patients using proton-pump inhibitors to esomeprazole at admission resulted in a spillover "extra cost" of €330,300 (95% CI 276,100; 383,800), whereas strictly switching to generic cetirizine resulted in savings of €7,700 (95% CI 4,100; 11,100). Overall we estimated that the RDF resulted in "extra costs" of €503,600 (95% CI 444,500; 563,100).

CONCLUSIONS

Evergreening strategies have been successful in maintaining market share in Geneva, offsetting competition by generics and cost containment policies. Hospitals may be contributing to increased overall healthcare costs by listing follow-on drugs in their RDF. Therefore, healthcare providers and policy makers should be aware of the impact of evergreening strategies.

Implementing the new oral anticoagulants into the hospital formulary

The new oral anticoagulants may prove to be one of most significant innovations in clinical practice in the past 60 years. Apixaban and rivaroxaban are direct inhibitors of Factor Xa, while dabigatran inhibits Factor IIa. The predictable pharmacological profile of these new agents allows physicians to prescribe these drugs without the need for routine coagulation monitoring, which is the mainstay of warfarin therapy. In addition, these new agents have not been shown to have any food interactions and minimal drug-drug interactions, interactions are limited to the p-glycoprotein (p-Gp) transporter or cytochrome P450 (CYP450) system, each drug is unique in its drug interaction profile, as will be discussed below. These unique pharmacokinetics profiles may usher in for clinicians a new era of managing thromboembolic disorders. In this article, the pharmacology of these new oral anticoagulants will be reviewed along with the major clinical trials evaluating the use of these agents for thromboembolic prophylaxis in patients undergoing total hip and knee arthroplastic surgery, the treatment of venous thromboembolic disorders and stroke prevention in atrial fibrillation. Am. J. Hematol., 2012. © 2012 Wiley Periodicals, Inc.

A prescription for improving drug formulary decision making

Gordon Schiff and colleagues present a new tool and checklist to help formularies make decisions about drug inclusion and to guide rational drug use.

Optimization education after project implementation: sharing "lessons learned" with staff

Implementations involving healthcare technology solutions focus on providing end-user education prior to the application going "live" in the organization. Benefits to postimplementation education for staff should be included when planning these projects. This author describes the traditional training provided during the implementation of a bar-coding medication project and then the optimization training 8 weeks later.

Anticonvulsant use after formulary status change for brand-name second-generation anticonvulsants

BACKGROUND

Anticonvulsant medications are commonly used for off-label indications. However, managed care organizations can restrict utilization of medication to indicated uses only.

OBJECTIVE

To evaluate the pattern of off-label use of second-generation anticonvulsants after implementing a formulary change.

METHODS

We did a retrospective analysis of an administrative pharmacy claims database for a managed care plan with more than 1 million members continuously enrolled during 2004-2005. The study evaluated off-label use and explored pharmacy utilization patterns (by physician specialty, region, plan type, age, sex, copayment) across the study population following the formulary change.

RESULTS

A total of 10,185 patients had at least 1 pharmacy claim (total of 137,638 claims) for a second-generation anticonvulsant during the study period. Most members were female (68%), and 4.9% were <18 years old. A total of 3986 of 4698 patients (84.8%) and 4600 of 5487 patients (83.8%) had anticonvulsants prescribed for off-label use in 2004 and 2005, respectively (P = .162). The off-label usage pattern varied for individual anticonvulsants in 2004 and 2005 (P <.050), which may have been because of the change to nonpreferred coverage. Primary care physicians accounted for 41.3% of the prescribing of second-generation anticonvulsants for off-label uses, followed by neurologists (9.4%), psychiatrists (2.8%), and other (46.5%). The coverage change resulted in cost savings for the plan of $0.16 per member per month.

CONCLUSIONS

The off-label usage pattern varied for individual anticonvulsants in 2004 and 2005. Future considerations for controlling off-label use may include requiring prior authorization and provider education.

The cost effectiveness and budget impact of natalizumab for formulary inclusion

BACKGROUND

Crohn's disease (CD) and multiple sclerosis (MS) are debilitating autoimmune diseases, which represent a substantial cost burden in the context of managed care. As a corollary, there is an unmet pharmacotherapeutic need in patient populations with relapsing forms of MS, in addition to populations with moderately to severely active CD with evidence of inflammation who have experienced an inadequate response to other mainstream therapies. The purpose of this study was to analyze the clinical and economic data associated with natalizumab (Tysabri) and to determine the potential impact of its formulary inclusion in a hypothetical health plan.

FINDINGS

Regarding MS, the implemented cost-effectiveness and budget-impact models demonstrated an anticipated reduction in relapse rate of 67% over 2 years, and a total therapy cost of $72,120 over 2 years, equating to a cost per relapse avoided of $56,594. With respect to the model assumptions, the market share of natalizumab would experience an increase to 8.5%, resulting in a total per-member, per-month healthcare cost increase of $0.003 ($0.002 for pharmacy costs and $0.001 for medical costs). Regarding CD, over a 2-year period outlined by the model, natalizumab produced the highest average time in remission, steroid-free remission, and remission or response in comparison to the other agents. The mean total costs associated with the initiation of natalizumab, infliximab, and adalimumab were $68,372, $62,090, and $61,796, respectively. Although natalizumab's costs were higher, the mean time spent in remission while on this medication was 4.5 months, as opposed to 2.4 months for infliximab and 2.9 months with adalimumab. This shift in market share was used to estimate the change in total costs (medical + pharmacy), and the per-member per-month change for the model's base case was calculated to be $0.035.

LIMITATIONS

The aforementioned cost-effectiveness results for natalizumab in the treatment for CD and MS were limited by the model's predetermined assumptions. These assumptions include anticipated reduction in relapse rate after 2 years of therapy and acquisition costs in the MS model, as well as assuming a certain percentage of patients were primary and secondary failures of TNFalpha inhibitor therapy in the CD model.

CONCLUSION

The evidence presented here demonstrates that natalizumab provides clinical practitioners with another tool in their fight against both MS and CD, albeit by way of a different mechanism of action. After a thorough review of the evidence, the authors find that natalizumab has been shown to be relatively cost effective in the treatment of both conditions from a payer perspective; the therapy adds a new option for those patients for whom conventional treatment was unsuccessful.

Introduction of ertapenem into a hospital formulary: effect on antimicrobial usage and improved in vitro susceptibility of Pseudomonas aeruginosa

After ertapenem was added to the formulary of a 344-bed community teaching hospital, we retrospectively studied its effect on antimicrobial utilization and on the in vitro susceptibility of various antimicrobial agents against Pseudomonas aeruginosa. Three study periods were defined as preintroduction (months 1 to 9), postintroduction but before the autosubstitution of ertapenem for ampicillin-sulbactam (months 10 to 18), and after the policy of autosubstitution (months 19 to 48) was initiated. Ertapenem usage rose slowly from introduction to a range of 36 to 48 defined daily doses/1,000 patient days (DDD) with a resultant decrease in ampicillin-sulbactam usage due to autosubstitution. Imipenem usage peaked 6 months after the introduction of ertapenem and started to decline coincidently with the increased use of ertapenem. During the second period, imipenem usage decreased (slope = -1.28; P = 0.002). Prior to the introduction of ertapenem, the susceptibility of P. aeruginosa to imipenem increased from 61 to 81% at month 7 but then decreased slightly to 67% at month 9. After the introduction of ertapenem, susceptibility continued to increase; the increasing trend was significant (slope = 1.74; P < 0.001). In the third period, the median susceptibility (interquartile range) was 88% (82 to 95%). This change appeared related to decreased imipenem usage. For every unit decrease in the monthly DDD of imipenem, there was an increase of 0.38% (P = 0.008) in the susceptibility of P. aeruginosa to imipenem in the same month. Ertapenem was effective in our antimicrobial stewardship program and may have helped improve the P. aeruginosa antimicrobial susceptibility to imipenem by decreasing the unnecessary usage and selective pressure of antipseudomonal agents.