Antibiotic resistance in the intensive care unit

Antimicrobial resistance has emerged as an important determinant of outcome for patients in the intensive care unit (ICU). This is largely due to the administration of inadequate antimicrobial treatment, which is most often related to bacterial antibiotic resistance. In addition, the escalating problem of antimicrobial resistance has substantially increased overall health care costs. This increase is a result of prolonged hospitalizations and convalescence associated with antibiotic treatment failures, the need to develop new antimicrobial agents, and the implementation of broader infection control and public health interventions aimed at curbing the spread of antibiotic-resistant pathogens. Intensive care units are unique because they house seriously ill patients in confined environments where antibiotic use is extremely common. They have been focal points for the emergence and spread of antibiotic-resistant pathogens. Effective strategies for the prevention of antimicrobial resistance in ICUs have focused on limiting the unnecessary use of antibiotics and increasing compliance with infection control practices. Clinicians caring for critically ill patients should consider antimicrobial resistance as part of their routine treatment plans. Careful, focused attention to this problem at the local ICU level, using a multidisciplinary approach, will have the greatest likelihood of limiting the development and dissemination of antibiotic-resistant infections.

Antimicrobial stewardship

Antimicrobial stewardship is a key component of a multifaceted approach to preventing emergence of antimicrobial resistance. Good antimicrobial stewardship involves selecting an appropriate drug and optimizing its dose and duration to cure an infection while minimizing toxicity and conditions for selection of resistant bacterial strains. Studies conducted over the years indicate that antibiotic use is unnecessary or inappropriate in as many as 50% of cases in the United States, and this creates unnecessary pressure for the selection of resistant species. Because the pharmaceutical industry pipeline for new antibiotics has been curtailed in recent years, and it may be >/=10 years before important new antibiotics to treat certain resistant bacteria find their way to market, a premium has been set on maintaining the effectiveness of currently available agents. Several strategies, including prescriber education, formulary restriction, prior approval, streamlining, antibiotic cycling, and computer-assisted programs have been proposed to improve antibiotic use. Although rigorous clinical data in support of these strategies are lacking, the most effective means of improving antimicrobial stewardship will most likely involve a comprehensive program that incorporates multiple strategies and collaboration among various specialties within a given healthcare institution. Computer-assisted software programs may be especially useful in implementing these comprehensive programs. The antimicrobial stewardship program at the Hospital of the University of Pennsylvania, which has been shown to improve appropriateness of antibiotic use and cure rates, decrease failure rates, and reduce healthcare-related costs, is used as an example in support of this multifaceted, multidisciplinary approach. At this time, data from well-controlled studies examining the effect of antibacterial stewardship on emergence of resistance are limited, but available data suggest that good antibiotic stewardship reduces rates of Clostridium difficile-associated diarrhea, resistant gram-negative bacilli, and vancomycin-resistant enterococci.

Reduction in the incidence of methicillin-resistant Staphylococcus aureus and ceftazidime-resistant Klebsiella pneumoniae following changes in a hospital antibiotic formulary

In 1995, changes in our hospital formulary were made to limit an outbreak of vancomycin-resistant enterococci and resulted in decreased usage of cephalosporins, imipenem, clindamycin, and vancomycin and increased usage of beta-lactam/beta-lactamase-inhibitor antibiotics. In this report, the effect of this formulary change on other resistant pathogens is described. Following the formulary change, there was a reduction in the monthly number (mean +/- SD) of patients with methicillin-resistant Staphylococcus aureus (from 21.9 +/- 8.1 to 17.2 +/- 7.2 patients/1,000 discharges; P = .03) and ceftazidime-resistant Klebsiella pneumoniae (from 8.6 +/- 4.3 to 5.7 +/- 4.0 patients/1,000 discharges; P = .02). However, there was an increase in the number of patients with cultures positive for cefotaxime-resistant Acinetobacter species (from 2.4 +/- 2.2 to 5.4 +/- 4.0 patients/1,000 discharges; P = .02). Altering an antibiotic formulary may be a possible mechanism to contain the spread of selected resistant pathogens. However, close surveillance is needed to detect the emergence of other resistant pathogens.

Long‐Term Antibiotic Cost Savings from a Comprehensive Intervention Program in a Medical Department of a University‐Affiliated Teaching Hospital

We tested a low-cost, multifaceted intervention program comprising formulary restriction measures, continued comprehensive education, and guidelines to improve in-hospital use of antibiotics and related costs. In a short-term analysis, total antibiotic consumption per patient admitted, which was expressed as defined daily doses (DDD), decreased by 36% (P < .001), and intravenous DDDs decreased by 46% (P < .01). Overall expenditures for antibiotic treatment decreased by 53% (100 US dollars per patient admitted). The 2 main cost-lowering factors were a reduction in prescription of antibiotics (35% fewer treatments; P < .0001) and more diligent use of 5 broad-spectrum antibiotics (23% vs. 10% of treatments; P = .001). Quality of care was not compromised. A pharmacy-based, prospective, long-term surveillance of DDDs and costs over 4 years showed an ongoing effect. This comprehensive intervention program, which aimed to reduce antibiotic consumption and costs, was highly successful and had long-lasting effects.

Antimicrobial stewardship programs: how to start and steer a successful program

BACKGROUND

Antimicrobial stewardship programs (ASPs) promote the appropriate use of antimicrobials by selecting the appropriate dose, duration, and route of administration. The appropriate use of antimicrobials has the potential to improve efficacy, reduce treatment-related costs, minimize drug-related adverse events, and limit the potential for emergence of antimicrobial resistance.

OBJECTIVE

To summarize ASP tactics that can improve the appropriate use of antimicrobials in the hospital setting. Several measures can be used to implement such programs and gain multidisciplinary support while addressing common barriers.

SUMMARY

Implementation of an ASP requires a multidisciplinary approach with an infectious diseases physician and a clinical pharmacist with infectious diseases training as its core team members. As identified by recently published guidelines, 2 proactive strategies for promoting antimicrobial stewardship include: (1) formulary restriction and pre-authorization, and (2) prospective audit with intervention and feedback. Other supplemental strategies involve education, guidelines and clinical pathways, antimicrobial order forms, de-escalation of therapy, intravenous-to-oral (IV-to-PO) switch therapy, and dose optimization. Several barriers exist to successful implementation of ASPs. These include obtaining adequate administrative support and compensation for team members. Gaining physician acceptance can also be challenging if there is a perceived loss of autonomy in clinical decision making.

CONCLUSION

ASPs have the potential to reduce antimicrobial resistance, health care costs, and drug-related adverse events while improving clinical outcomes. The efforts and expense required to implement and maintain ASPs are more than justified given their potential benefits to both the hospital and the patient.

Practices to improve antimicrobial use at 47 US hospitals: the status of the 1997 SHEA/IDSA position paper recommendations. Society for Healthcare Epidemiology of America/Infectious Diseases Society of America

OBJECTIVE

To determine the status of programs to improve antimicrobial prescribing at select US hospitals.

DESIGN

Cross-sectional survey.

PARTICIPANTS AND SETTING

Pharmacy and infection control staff at all 47 hospitals participating in phase 3 of Project Intensive Care Antimicrobial Resistance Epidemiology.

RESULTS

All 47 hospitals had some programs to improve antimicrobial use, but the practices reported varied considerably. All used a formulary, and 43 (91%) used it in conjunction with at least one of the other three antimicrobial-use policies evaluated: stop orders, restriction, and criteria-based clinical practice guidelines (CPGs). CPGs were reported most commonly (70%), followed by stop orders (60%) and restriction policies (40%). Although consultation with an infectious disease physician (70%) or pharmacist (66%) was commonly used to influence initial antimicrobial choice, few (40%) reported a system to measure compliance with these consultations.

CONCLUSIONS

In most hospitals surveyed, practices to improve antimicrobial use, although present, were inadequate based on recommendations in a Society for Healthcare Epidemiology of America and Infectious Disease Society of America joint position paper. There is room to improve antimicrobial-use stewardship at US hospitals.

Pharmacy benefit management, cost-effectiveness analysis and drug formulary decisions

Pharmacy benefit management companies (PBMs) have evolved over the past decade in response to the increased demand for health care cost containment. Their activities include the implementation of drug formularies and the negotiation of rebates from manufacturers. Our analysis of this industry is based on interviews and materials provided by the top five ranked PBM companies which account for over 80% of beneficiaries covered within formulary plans. The formularies of these companies are relatively inclusive, but they are becoming more restrictive over time. At present the use of cost-effectiveness (C-E) studies in the formulary decisions of PBMs has been limited. In this regard, the surveyed PBMs emphasized that most C-E studies have not compared therapeutic substitutes in populations with characteristics that are similar to those of their clients. Pharmacy benefit management companies also have had strong incentives to focus narrowly on drug costs because they typically manage drug benefits on a "carved-out" basis. However, PBMs anticipate a growing future role in the integrated management of patient care (disease management) for certain high cost chronic diseases and conditions. All of the leading firms we surveyed have disease management programs in development. The importance of C-E studies to PBM decisions is expected to increase significantly as disease management programs are implemented. The data infrastructure inherent to the PBM industry and the increasing number of employees with advanced training in pharmacoeconomics will permit firms to perform their own internal C-E studies. They are also establishing various alliances and joint ventures with drug manufacturers, health maintenance organizations, and academic institutions to perform these analyses. The leading PBMs tend to favor active participation in the development of methodological approaches to C-E studies over government regulations such as those proposed by the FDA in 1995.

Hospital pharmacy decisions, cost containment, and the use of cost-effectiveness analysis

The key hypothesis of the study was that hospital pharmacies under the pressure of managed care would be more likely to adopt process innovations to assure less costly and more cost-effective provision of care. We conducted a survey of 103 hospitals and analyzed secondary data on cost and staffing. Compared to the size of the reduction in length of stay, changes in the way that a day of care is delivered appear to be minor, even in areas with substantial managed care share. The vast majority of hospitals surveyed had implemented some form of therapeutic interchange and generic substitution. Most hospitals used some drug utilization guidelines, but as of mid 1995 these were not yet important management tools for hospital pharmacies. To our knowledge, ours was the first survey to investigate the link between hospital formularies and use of cost-effectiveness analysis. At most cost-effectiveness was a minor tool in pharmaceutical decision making in hospitals at present. We could determine no differences in use of such analyses by managed care market share in the hospital's market share. One impediment to the use of cost-effectiveness studies was the lack of timeliness of studies. Other stated reasons for not using cost-effectiveness analysis more often were: lack of information on hospitalized patients and hence on the potential cost offsets accruing to the hospital: lack of independent sponsorship, and inadequate expertise in economic evaluation.

Benchmark analysis of strategies hospitals use to control antimicrobial expenditures

Hospital expenditures on antimicrobial drugs, antimicrobial management practices, and the effects of these practices were studied. A survey on institutional budget, size, and staffing; intensive care unit drug costs and use evaluations; and pharmacy expenditures, including antimicrobial costs, for 1993 and 1994 was sent to 122 hospitals. The written survey was followed by telephoned questions regarding each institution's antimicrobial management and expenditures, and any perceived link between the two. Hospitals were grouped by size and type, data were normalized to costs per occupied bed and costs per occupied bed per case mix index, and averages for each size category were calculated for general institutional information and expenses per antimicrobial. Eighty-eight institutions (72%) responded. Although 61% to 74% of the respondents used an antimicrobial formulary to restrict drug choices and control costs, average total antimicrobial expenses increased by more than $300 per occupied bed between 1993 and 1994. Only 7% of the institutions saw decreased costs of $500 or more per occupied bed. The most common reasons for these decreases were restructuring of pricing contracts and implementation of educational programs. The replacement of one formulary alternative with another led to increases in the use of antimicrobials other than the replacement drug and often did not produce savings. The replacement of one formulary antimicrobial with another led more to costshifting than to overall savings.

ASHP national survey of pharmacy practice in hospital settings: prescribing and transcribing--2001

Results of the 2001 ASHP national survey of pharmacy practice in hospital settings that pertain to prescribing and transcribing are presented. A stratified random sample of pharmacy directors at 1091 general and children's medical-surgical hospitals in the United States was surveyed by mail. SMG Marketing Group, Inc., supplied data on hospital characteristics; the survey sample was drawn from SMG's hospital database. The response rate was 49.0%. During 2001, nearly all hospitals are estimated to have pharmacy and therapeutics (P&T) committees that meet an average of seven times per year. It is estimated that more than 90% of P&T committees are responsible for formulary development and management, drug policy development, adverse-drug-reaction review, and medication-use evaluation. More than 90% of hospitals use clinical and therapeutic, cost, and pharmacoeconomic information in the formulary management process, while nearly two thirds consider quality-of-life issues. Nearly 70% use clinical practice guidelines in the formulary management process, and 78% have a medication-use evaluation program designed to improve prescribing. Pharmacists in more than 75% of hospitals provide consultations on drug information, dosage adjustments for patients with renal impairment, antimicrobials, and pharmacokinetics. Further, a majority of hospitals ensure accurate transcription of medication orders by clarifying illegible orders before transcription or entry into medication administration records (MARs), using standardized prescriber order forms, requiring prescribers to countersign all oral orders, and reconciling MARs and pharmacy patient profiles at least daily. In 2001, large hospitals are most likely to use prescriber order-entry systems to improve patient safety and are least likely to require the reentry of medication orders into the pharmacy computer system. The 2001 ASHP survey results suggest that pharmacists in hospital settings have positioned themselves well to improve the prescribing and transcribing components of the medication-use process.

Multicenter hospital study on prescribing patterns for prophylaxis and treatment of complications of cirrhosis

OBJECTIVE

To describe the prescribing patterns for liver disease management.

METHODS

A multicenter cross-sectional prospective observational study was carried out in 25 Spanish hospitals. Inpatients, admitted to gastrointestinal and liver units with a diagnosis of liver cirrhosis, were included in five centrally assigned index days between February and June 1999. Information was collected about demographic variables and pharmacological treatments used on admission and recommended at discharge.

RESULTS

Five hundred and sixty-eight patients (70% men, mean age 61 years) were studied. Alcoholic cirrhosis of the liver accounted for 44% of the sample, ascites being the most prevalent complication. The most frequent diuretic schedule on admission was the combination of spironolactone and furosemide at a ratio of 1 (100 mg/40 mg). Hospitalization resulted in an increase in the percentage of patients that received the combination at a ratio higher than 1. Diuretics were a major cause of adverse drug events on admission (7.5%). Ulcer-healing drugs showed a notable increase at discharge (35%; range 10-59%) compared with 24% (6-37%) on admission. Utilization rates at discharge were 65% (59-74%) for diuretics, 51% (38-76%) for laxatives, 31% (0-75%) for vitamin K, 24% (4-53%) for beta-adrenergic blocking agents, and 13% (0-47%) for nitrates, which were significantly higher than on admission.

CONCLUSION

These results provide the first quantitative data of drug utilization in liver disease and highlight the wide variability in prescribing practices across centers and the higher than expected use of non-evidence-based treatments, especially vitamin K and antiulcer drugs.

Impact of a web-based antimicrobial approval system on broad-spectrum cephalosporin use at a teaching hospital

OBJECTIVE

To achieve sustained improvement in use of cefotaxime and ceftriaxone (CEFX) in a major teaching hospital, as measured against national antibiotic guidelines.

DESIGN AND SETTING

Pre- and post-intervention survey of CEFX use in the Royal Melbourne Hospital, a tertiary hospital in Melbourne, Victoria.

INTERVENTION

Web-based antimicrobial approval system linked to national antibiotic guidelines was developed by a multidisciplinary team and implemented in March 2001.

MAIN OUTCOME MEASURES

Change in rate of CEFX use (defined daily doses [DDDs] per 1000 acute occupied bed days) over 8 months pre- and 15 months post-intervention; concordance of indication for CEFX with national antibiotic guidelines pre- and post-intervention.

RESULTS

CEFX use decreased from a mean of 38.3 DDDs/1000 bed days pre-intervention to 15.9, 18.7 and 21.2 DDDs/1000 bed days at 1, 4 and 15 months post-intervention. Concordance with national antibiotic guidelines rose from 25% of courses pre-intervention to 51% within 5 months post-intervention (P < 0.002). Gentamicin use also increased, from a mean of 30.0 to 48.3 DDDs/1000 bed days (P = 0.0001).

CONCLUSION

The web-based antimicrobial approval system achieved a sustained reduction in CEFX use over 15 months as well as increased prescribing concordance with antibiotic guidelines. It has potential for linking to electronic prescribing and for wider use for other drugs, as well as for research into the epidemiology of antibiotic use.

Spontaneous reporting of adverse drug reactions to non-steroidal anti-inflammatory drugs. A report from the Spanish System of Pharmacovigilance, including an early analysis of topical and enteric-coated formulations

Non-steroidal anti-inflammatory drugs (NSAIDs) are the third most commonly prescribed group of drugs in Spain. We present here the profile of adverse drug reactions (ADRs) attributed to them and reported to the Spanish System of Pharmacovigilance (SSPV) between 1983 and 1991, together with a preliminary analysis of topical, slow-release (SR) and enteric-coated (EC) preparations. Out of 18,348 reports of ADRs included in the SSPV database, 1609 (8.8%) implicated an NSAID. NSAIDs ranked second after antibiotics (15.1% of all reports) among the most commonly implicated drugs. Half of the patients were more than 55 years old, and 60% were women. Diclofenac (364 reports), piroxicam (282), indomethacin (197), naproxen (155), and ketoprofen (137) were the most commonly implicated NSAIDs in reports of ADRs. The most commonly reported ADRs were gastrointestinal (39%), cutaneous (20%), and those affecting the central and peripheral nervous system (9%). Seven reactions had a fatal outcome, and 138 were considered life threatening. Forty-nine reports included previously undescribed ADRs. There were 98 reports describing ADRs attributed to topical NSAIDs; 5 of these described 11 general reactions, such as duodenal ulcer, gastrointestinal bleeding, diarrhoea, dyspnoea, facial oedema, aggravation of bronchospasm, and angioedema. One hundred and sixty-eight reports referred to SR and EC preparations. The ratio of gastrointestinal to non-gastrointestinal reactions to SR-EC diclofenac was higher in the case of SR-EC diclofenac than in the case of plain diclofenac (P = 0.037); similarly, the ratio of CNS to non-CNS reactions to SR-EC indomethacin was also higher than the corresponding ratio with plain indomethacin (P = 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)

Trends in hospital antibiotic prescribing after introduction of an antibiotic policy

Trends in antibiotic prescribing in Grampian were monitored prospectively for seven years from 1986 using computerised ward stock lists and laboratory data relating to all in-patient and out-patient treatments in all Grampian hospitals serving a population of 500,000. The main outcome measures were the number of antibiotics available for routine and restricted uses, annual expenditure and defined daily doses (DDDs) of high expenditure antimicrobial agents. An antibiotic committee introduced a policy and formulary in the third year of the study which had only limited success in controlling prescribing. During the period of the study 30 new antibiotics were considered for inclusion in the hospital formulary, but only seven were incorporated, and all for restricted use only. Despite this, expenditure on antibiotics has more than doubled since 1986, two thirds of the increase being due to the use of new drugs. There was also an increased use of older antibiotics (DDDs increased by 33%), often for no clear reasons, and an overall increase of 46% in DDDs. Antibiotics have increased from 11.9-18.7% as a proportion of the drug budget. These findings highlight the current difficulty in controlling prescribing budgets, the increasing use of antibiotics and the consequent spread of resistance.

Prescribing to older ED patients

The purpose of this article is to assist emergency physicians in selecting safe and effective drug therapy for seniors. Because safer alternatives exist, medications on the Beers list of potentially inappropriate medications should generally be avoided. We also review risks associated with several classes of medications: nonsteroidal anti-inflammatory drugs, benzodiazepines, and anticholinergic medications. They are associated with adverse outcomes when taken by older adults and should be used with caution. We also address the use of opioid medications in seniors. Although they are not without risk, opioids are generally safe with slow titration, precautions, and a bowel regimen to prevent constipation. Prescribers should also consider the need for estimating creatinine clearance when prescribing medications that require dosage adjustment in the setting of renal insufficiency. Two areas in need of research are identifying the proper dosing and safety of medications in seniors and prescribing with electronic decision support to assist in prescribing decisions.

What constitutes evidence in hospital new drug decision making?

In National Health Service hospitals in the UK the introduction of new drugs is controlled by a local Drug and Therapeutics Committee (DTC), which is expected to apply the principles of evidence-based medicine (EBM). In the light of growing expenditure on drugs, there is interest in how the decisions are made that lead to the local acceptance or rejection of a new drug. In this study the DTCs of two general hospitals were observed, tape-recorded and analysed to determine what was considered as evidence and how it was used in decision making. Evidence, as constituted by DTC members, was issues that affected the decision-making process and included: clinical trial data, cost, pre-existing prescribing of the drug, pharmaceutical company activities, decisions of other DTCs, patient demand, clinician excitement, and personality of the applicant. Debate usually started with a discussion of the scientific evidence, then the cost would be considered. Often this evidence was either inadequate or insufficient enough for a locally implementable decision and further types of evidence would be brought in to try and estimate the likely impact of adopting the new drug. EBM, while used in decision making, was supplemented by local knowledge, although decisions were accounted for in the language of scientific rationality. Both abstract scientific rationality and the local rationality of practical healthcare provision were present in the decisions of the DTCs on the adoption, or otherwise, of new drugs into local formularies and healthcare. We suggest the coming together of local and abstract in local decision-making needs to be taken into account when formulating policy and providing decision support.

Routine cycling of antimicrobial agents as an infection-control measure

Antimicrobial cycling is the deliberate, scheduled removal and substitution of specific antimicrobials or classes of antimicrobials within an institutional environment (either hospital-wide or confined to specific units) to avoid or reverse the development of antimicrobial resistance. True antimicrobial cycling requires a return to the antimicrobial(s) that were first used. Testing of the hypothesis that cycling will result in a lower prevalence of resistance is ongoing, mostly occurs within intensive care units, and largely involves cycling regimens targeted for treatment of suspected gram-negative bacterial infections. Unfortunately, there has been insufficient study to determine whether any meaningful impact on resistance has occurred as a result of a cycling program. Mathematical models question the usefulness of cycling as an infection-control method. Published studies demonstrate that cycling may be one way to change prescribing practices by clinicians without sacrificing patient safety. However, optimizing antimicrobial use through traditional and novel methods (e.g., computer decision support) should not be abandoned.

Results of an antimicrobial control program at a university hospital

PURPOSE

The results of the first five years of an ongoing antimicrobial control program are reported.

METHODS

In 1998, a multidisciplinary antimicrobial subcommittee of the pharmacy and therapeutics committee of a university hospital was formed and charged with making formulary interventions in an effort to reduce rising antimicrobial resistance rates and drug expenditures. In 1999, a number of measures were implemented for controlling antimicrobial use. Selected antimicrobials with the potential for inappropriate use or whose inappropriate use had been documented were placed in the control of physicians in the infectious diseases (ID) division. Prior approval by an ID physician was required before the pharmacy could dispense these agents. Other key interventions included removal of ceftazidime and cefotaxime from the formulary, restriction of vancomycin and carbapenem use, and replacement of ciprofloxacin with levofloxacin as the sole fluoroquinolone on the formulary. Data regarding antimicrobial use and expenditures between 1998 and 2002 were compared and analyzed.

RESULTS

Antimicrobial use was reduced by 80% for third-generation cephalosporins and 15% for vancomycin following the implementation of the new antimicrobial policies. Antimicrobial-resistance patterns for many important gram-negative pathogens, including Pseudomonas aeruginosa, demonstrated a reversal of previous increases. In addition, the rate of methicillin-resistant Staphylococcus aureus decreased by an average of 3% each year from 1999 to 2002. Pharmacy expenditures for all antimicrobials, including antiviral, antifungal, and antibacterial agents, decreased 24.7%, with a cumulative cost saving of 1,401,126 US dollars, without inflation assumptions.

CONCLUSION

The implementation of an antimicrobial control program decreased the use of selected antimicrobial agents and resulted in substantial reduction of expenditures for antimicrobials.

Sorbitol content of selected oral liquids

OBJECTIVE

Excipients in pharmaceuticals usually are considered inert, and may be overlooked in the differential diagnosis of diarrhea. Sorbitol-containing medicinal liquids are capable of inducing osmotic diarrhea. We reviewed the oral liquids in our formulary to determine their sorbitol content and to evaluate the availability of this information.

DESIGN

The oral liquids stocked by our hospital were determined through a computer search and manual inspection of the pharmacy storeroom. Three common sources of drug information were consulted to determine each product's sorbitol content: manufacturers' product information, American Hospital Formulary Service (AHFS) Drug Information 91, and Facts and Comparisons Drug Information. We then contacted each manufacturer by mail or telephone to verify the information.

SETTING

The study was conducted at the University of Cincinnati Hospital, a tertiary-care, teaching hospital.

RESULTS

A total of 129 products (98 chemical entities) were reviewed. Fifty-four (42 percent) of the products examined contained sorbitol. The frequency of sorbitol presence by liquid type was: solutions (33 percent), suspensions (43 percent), syrups (59 percent), elixirs (43 percent), concentrates (67 percent), drops (33 percent), tinctures (0 percent), and emulsions (0 percent). The percentage of listings indicating the presence of sorbitol was: manufacturer's product information (79 percent), Facts and Comparisons (52 percent), and AHFS Drug Information 91 (13 percent). Only three of the 54 products had the exact sorbitol content stated in any source.

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.