Evidence-Based, Multidisciplinary Approach to the Development of a Crotalidae Polyvalent Antivenin (CroFab) Protocol at a University Hospital

Background:

Several thousand people are bitten annually by venomous snakes in the US. While the development of ovine Crotalidae polyvalent immune Fab antivenin (FabAV) for Crotalinae snakebite envenomations has greatly changed the way this clinical presentation is treated, multiple issues complicate its use. From patient assessment and evaluation, to medication preparation and administration, to the management of adverse drug reactions, the use of this antidote carries with it multiple points of possible medication variances. The inappropriate use of this agent can result in adverse patient consequences and a significant financial burden for both the hospital and the patient.

Objective:

To describe an evidence-based, multidisciplinary approach that was taken to ensure optimal, safe, and cost-effective treatment of patients with FabAV.

Methods:

Following an analysis of the available literature, a multidisciplinary committee was formed to construct a protocol for use of FabAV. This group included clinical pharmacists, pharmacy administrators, emergency medicine physicians who specialized in wilderness medicine and pharmacy residents.

Results:

A multidisciplinary FabAV usage protocol was constructed and implemented to ensure appropriate patient evaluation, FabAV use and preparation, monitoring, and follow-up. This protocol was based on the available literature and the expert opinion of the committee. Through the use of a 24-hour in-house pharmacy resident on-call system, clinical pharmacy services were provided to ensure a multidisciplinary approach to the care of these patients emergently. Although limited, initial data show that this approach is effective and may result in substantial cost savings.

Conclusions:

Initial results from implementation of a protocol for use of FabAV have limited inappropriate use, reduced medication wastage, and decreased costs.

Evaluation of adverse events noted in children receiving continuous infusions of dexmedetomidine in the intensive care unit

OBJECTIVES

Dexmedetomidine is an α(2)-adrenergic receptor agonist with sedative and analgesic effects in mechanically ventilated adults and children. Safety and efficacy data are limited in children. The purpose of this study is to retrospectively identify the incidence and types of adverse events noted in children receiving continuous infusions of dexmedetomidine and evaluate potential risk factors for adverse events.

METHODS

Between July 1, 2006, and July 31, 2007, data were collected on all children (< 18 years) who received continuous infusions of dexmedetomidine. Data collection included demographics, dexmedetomidine regimen, and type/number of adverse events. The primary endpoint was the total number of adverse events noted, including: transient hypertension, hypotension, neurological manifestations, apnea, and bradycardia. Secondary endpoints included categorization of each type of adverse event and an assessment of risk factors. A logistic regression model was used to assess the relationship of adverse events with independent variables including length of ICU stay, cumulative dose, peak infusion rate, duration of therapy, PRISM III score, and bolus dose.

RESULTS

Thirty-six patients received dexmedetomidine representing 41 infusions. The median age was 16 months (range, 0.1-204 months) and median PRISM III score was 2 (range, 0-18). Eighteen (43.9%) patients received a bolus dose of dexmedetomidine. The median cumulative dose (mcg/kg) and peak dose (mcg/kg/hr) were 8.5 (range, 2.2-193.7) and 0.5 (range, 0.2-0.7), respectively. Dexmedetomidine was continued for a median of 20 (range, 3-263) hours. Six (14.6%) patients were slowly tapered off the continuous infusions. Twenty-one adverse events were noted in 17 patients, including 4 neurologic manifestations. Fourteen patients required interventions for adverse events. ICU length of stay was the only independent risk factor (p=0.036) for development of adverse events.

CONCLUSIONS

Several potential adverse events were noted with dexmedetomidine continuous infusions including possible neurological manifestations. Further studies are needed looking at adverse events associated with dexmedetomidine use in the pediatric population.

Neurologic Withdrawal Symptoms Following Abrupt Discontinuation of a Prolonged Dexmedetomidine Infusion in a Child

Dexmedetomidine is a α2-adrenergic agonist which possesses sedative, analgesic, and anxiolytic properties. It is approved for short-term use in adults to provide sedation while mechanically ventilated and for noninvasive procedural sedation. An increased number of anecdotal reports describe the use dexmedetomidine in children. Cardiovascular withdrawal symptoms have been reported in the literature. However, there have been few published reports of neurologic withdrawal symptoms following discontinuation of prolonged infusions of dexmedetomidine. We describe a 2 year-old child who received a prolonged continuous infusion (263 hours) of dexmedetomidine as an adjunctive sedative agent. Following abrupt discontinuation of dexmedetomidine, the patient presented with symptoms suggestive of neurological withdrawal. The symptoms gradually resolved over two days without further intervention, and the patient had full resolution of symptoms and was discharged home with no further neurologic sequelae.

Neurologic withdrawal symptoms following abrupt discontinuation of a prolonged dexmedetomidine infusion in a child

Dexmedetomidine is a α(2)-adrenergic agonist which possesses sedative, analgesic, and anxiolytic properties. It is approved for short-term use in adults to provide sedation while mechanically ventilated and for noninvasive procedural sedation. An increased number of anecdotal reports describe the use dexmedetomidine in children. Cardiovascular withdrawal symptoms have been reported in the literature. However, there have been few published reports of neurologic withdrawal symptoms following discontinuation of prolonged infusions of dexmedetomidine. We describe a 2 year-old child who received a prolonged continuous infusion (263 hours) of dexmedetomidine as an adjunctive sedative agent. Following abrupt discontinuation of dexmedetomidine, the patient presented with symptoms suggestive of neurological withdrawal. The symptoms gradually resolved over two days without further intervention, and the patient had full resolution of symptoms and was discharged home with no further neurologic sequelae.

Evaluation of Adverse Events Noted in Children Receiving Continuous Infusions of Dexmedetomidine in the Intensive Care Unit

OBJECTIVES

Dexmedetomidine is an α2-adrenergic receptor agonist with sedative and analgesic effects in mechanically ventilated adults and children. Safety and efficacy data are limited in children. The purpose of this study is to retrospectively identify the incidence and types of adverse events noted in children receiving continuous infusions of dexmedetomidine and evaluate potential risk factors for adverse events.

METHODS

Between July 1, 2006, and July 31, 2007, data were collected on all children (&lt; 18 years) who received continuous infusions of dexmedetomidine. Data collection included demographics, dexmedetomidine regimen, and type/number of adverse events. The primary endpoint was the total number of adverse events noted, including: transient hypertension, hypotension, neurological manifestations, apnea, and bradycardia. Secondary endpoints included categorization of each type of adverse event and an assessment of risk factors. A logistic regression model was used to assess the relationship of adverse events with independent variables including length of ICU stay, cumulative dose, peak infusion rate, duration of therapy, PRISM III score, and bolus dose.

RESULTS

Thirty-six patients received dexmedetomidine representing 41 infusions. The median age was 16 months (range, 0.1–204 months) and median PRISM III score was 2 (range, 0–18). Eighteen (43.9%) patients received a bolus dose of dexmedetomidine. The median cumulative dose (mcg/kg) and peak dose (mcg/kg/hr) were 8.5 (range, 2.2–193.7) and 0.5 (range, 0.2–0.7), respectively. Dexmedetomidine was continued for a median of 20 (range, 3–263) hours. Six (14.6%) patients were slowly tapered off the continuous infusions. Twenty-one adverse events were noted in 17 patients, including 4 neurologic manifestations. Fourteen patients required interventions for adverse events. ICU length of stay was the only independent risk factor (p=0.036) for development of adverse events.

CONCLUSIONS

Several potential adverse events were noted with dexmedetomidine continuous infusions including possible neurological manifestations. Further studies are needed looking at adverse events associated with dexmedetomidine use in the pediatric population.

Lofexidine, an α2-Receptor Agonist for Opioid Detoxification

Objective:

To review the pharmacology, toxicology, pharmacokinetics, efficacy, adverse effects, drug interactions, and dosage guidelines for lofexidine, an α2-agonist, for opioid detoxification.

Data Sources:

Primary literature was identified through a MEDLINE search (1950–September 2009), EMBASE (1988–Juty 2009), International Pharmaceutical Abstracts (1970–September 2009), and the Cochrane Library (1996–September 2009) using the key words lofexidine and opioid withdrawal. Abstracts were included in the absence of published results of studies.

Study Selection and Data Extraction:

Studies published in English-language literature reporting on animal and human pharmacology, toxicology, and pharmacokinetics were included in addition to clinical trials using lofexidine for opioid detoxification in comparison to placebo or active controls.

Data Synthesis:

Lofexidine is an α2-agonist structurally related to clonidine. It is not an effective antihypertensive agent; however, it decreases the sympathetic outflow responsible for many opioid withdrawal symptoms. Nine clinical studies were reviewed representing 354 patients receiving lofexidine including a recent Phase 3 clinical trial. Eight studies involved comparisons of lofexidine to an opioid receptor agonist or clonidine for opioid detoxification. In these trials, lofexidine dosing was titrated to a maximum of 1.6–3.2 mg/day in divided doses for a total of 5–18 days. The data suggest that lofexidine has positive efficacy in reducing opioid withdrawal symptoms and is at least as effective as the opioid receptor agonists utilized for detoxification. Not all withdrawal symptoms are alleviated by α2-agonists, with many patients complaining of insomnia and aching. The most common adverse event with lofexidine in the Phase 3 trial was insomnia. Hypotension was also reported; however, the studies comparing clonidine with lofexidine suggest decreased incidence and severity of adverse events with lofexidine.

Conclusions:

Lofexidine appears to be a promising agent for opioid detoxification. If approved, it would be the first nonopioid agent approved for this indication. Further large-scale controlled studies are needed to identify the safest, most effective dosage regimen required to achieve opioid detoxification.

Evaluation of inpatient admissions and potential antimicrobial and analgesic dosing errors in overweight children

BACKGROUND

The prevalence of overweight/obesity in US children has increased over the past several decades. Routine use of weight-based dosing of medications could potentially result in over- or underdosing in these children.

OBJECTIVE

To determine the percentage of admissions of children with a body mass index (BMI) greater than or equal to the 85th percentile for age and sex and the mean error rate per admission in the overweight versus control group.

METHODS

We performed a retrospective, preliminary study of children aged 5-12 years who were admitted to a children's hospital over a period of 6 months. The overweight group included children with a BMI greater than or equal to the 85th percentile; the control group included children with a BMI less than the 85th percentile. Dose appropriateness was assessed, using 2 references. An overdose was defined as: (1) total mg/kg/day or mg/kg/dose greater than or equal to 110% of the maximum recommended pediatric dose, (2) total mg/day greater than the adult maximum recommended dose, or (3) greater than the recommended number of doses per day. An underdose was defined as: (1) total mg/kg/day or mg/kg/dose less than or equal to 90% of the minimum recommended pediatric dose, or (2) fewer than the recommended number of doses per day. Baseline comparisons between groups were done via Student's t-tests and chi2 analysis, when appropriate, with an a priori alpha of p less than or equal to 0.05.

RESULTS

A total of 839 admissions representing 699 patients were included. The overweight group included 278 (33.1%) admissions. Comparison of overall mean error rate per admission revealed a statistically significant increase in dosing errors for overweight patients (0.4 +/- 0.6 vs 0.3 +/- 0.6; p = 0.030), with underdose errors occurring more frequently than overdose errors (0.3 +/- 0.6 vs 0.2 +/- 0.5; p = 0.010).

CONCLUSIONS

Overweight children accounted for one-third of admissions, and the results of this study suggest that these patients are at greater risk for errors in dosing than are children of age- and sex-appropriate weight. This study did not assess clinical outcomes; however, overweight children could be at increased risk for therapeutic failures or adverse effects.

α2-Receptor Agonists for Treatment and Prevention of Iatrogenic Opioid Abstinence Syndrome in Critically Ill Patients

Objective:

To review the literature regarding the use of α2-agonists in the treatment and prevention of iatrogenic opioid abstinence syndrome (IOAS) in critically ill patients.

Data Sources:

Primary literature was identified through a search of MEDLINE (1950–June 2009), EMBASE (1988–June 2009), International Pharmaceutical Abstracts (1970–June 2009), and the Cochrane Library (1996–June 2009), using the names of individual α2-agonists and the following key words: children, opioid withdrawal, opioid, and adult. Relevant abstracts from the Society of Critical Care Medicine, reference citations from selected articles, and manufacturers’ product information were also reviewed.

Study Selection and Data Extraction:

All English-language articles identified from the data sources were evaluated. Three retrospective studies and 6 case reports/series representing 44 patients were included for analysis.

Data Synthesis:

Central α2-agonists are thought to minimize symptoms of IOAS by decreasing presynaptic outflow of catecholamines. Successful use of clonidine and dexmedetomidine for management of IOAS has been reported. Lofexidine, an α2-agonist not yet approved in the US, may offer similar withdrawal symptom relief but has yet to be studied in the intensive care setting. Although the quality of studies identified was limited, preliminary evidence does provide some support for the use of transdermal clonidine and injectable dexmedetomidine in the treatment and prevention of IOAS. These agents were shown to facilitate discontinuation of opioids and to minimize withdrawal symptoms with few reported adverse events.

Conclusions:

Central α2-agonists appear to be effective and safe second-line agents for treatment and prevention of IOAS. Further studies should be conducted to determine their role in the therapy of patients with IOAS.

Pediatric Pulmonary Hypertension: A Pharmacotherapeutic Review

Pulmonary hypertension in children is a disorder associated with increased pulmonary vascular resistance and arterial pressure, decreased cardiac output, and right-sided cardiac dysfunction that is caused by numerous etiologies. Although treatment will vary with underlying cause, pharmacological treatment has historically included inhaled nitric oxide and prostacyclin analogues. Over the past several years new agents have been added to the treatment armamentarium, including phosphodiesterase V inhibitors (eg sildenafil) and endothelin antagonists (eg bosentan). Further, more agents are currently under investigation for pulmonary hypertension in children including immunosuppressives and other endothelin antagonist entities. Limitations to treatment include the availability of appropriate, robust pediatric pharmacological data and constraints with dosage forms.

Utilisation of Crotalidae polyvalent immune fab (ovine) for Viperidae envenomations in children

Snakebite envenomations occur in 45,000 patients in the USA annually and are associated with morbidity especially in children and the elderly. Crotalidae polyvalent immune fab (ovine; FabAV) is a polyvalent antivenom derived from sheep for crotalid envenomations. Limited clinical trials are available in paediatric patients. A literature search using MEDLINE (1950-February 2008), International Pharmaceutical Abstracts (1970-February 2008), EMBASE (1988-February 2008) and Cochrane Library (1996-June 2008) was conducted using key words including: antivenom OR snakebites OR children OR Crotalid OR envenomations. All English-language articles were identified from data sources. Pertinent studies pertaining to FabAV in children and adolescents with crotalid envenomations were included for analysis. Ten papers were included for review, representing 47 children. Initial doses ranging from 2 to 18 g were administered and initial control was achieved in most children. Maintenance dosing was continued in 63.8% (30/47) of patients; 4.3% (2/47) of patients had episodes of venom recurrence. Adverse events were noted in 8.5% of children (4/47) when pooled for data analysis. FabAV appears to be a safe and effective agent for children with crotalid envenomations. Clinicians should adapt dosing recommendations used for adults until future large, well-designed trials can confirm the efficacy and safety from observation studies and case reports.

Combination thrombolytic and anti-platelet therapies in an infant with incomplete kawasaki disease and coronary aneurysms

A 3-month-old infant was transferred to our facility with persistent fever and concerns for septic shock. A 2-D echocardiogram revealed multiple coronary aneurysms and axillary and coronary artery thrombi, and a diagnosis of incomplete Kawasaki disease (KD) was established. Aggressive therapies including intravenous immunoglobulins, enoxaparin, abciximab, aspirin, and alteplase were used to decrease the size of the coronary aneurysms and inhibit further thrombus formation. After minimal change in the size of coronary aneurysms and in thrombus formation, clopidogrel was added. Approximately 2 weeks after initiation of these therapies, a decrease in the coronary aneurysm size was noted with no signs of thrombus. This case documents successful use of thrombolytic and combination anti-platelet agents (i.e., clopidogrel, abciximab, and aspirin) in an infant with KD and cardiovascular sequelae.

Utilizing Pharmacy Records to Assess Antibiotic Prescribing Patterns on the Incidence of Community-Acquired Methicillin-Resistant Staphylococcus aureus Infections in Children

OBJECTIVE To assess the effect of prior antibiotic therapy on the incidence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections in children.

METHODS This was a concurrent and retrospective review of antibiotic records for children &lt; 18 years of age with documented CA-MRSA infection identified between January 1, 2004, and December 31, 2005. Antibiotic records were compared against a control group. The primary outcome was the incidence of CA-MRSA using linear regression as a function of age and prior antibiotic therapy (i.e., 3 months prior to admission). Secondary objectives included a comparison of antibiotic courses and classes and a description of antibiotic susceptibilities in patients with CA-MRSA

RESULTS Data from 26 patients were included. Nine out of 51 patients (18%) with CA-MRSA were included. Another 17 children were enrolled in the control group. The median age was approximately 1.75 years (0.08–14 years) in the CA-MRSA group versus 2.75 years (0.005-15 years) in the control group. A statistical difference was noted in the number of patients with prior antibiotic exposure between the CA-MRSA and control group, 8 (88.9%) versus 6 (35.3%), respectively (P = .01). Antibiotic exposure was found to be a significant independent risk factor (P = .005; 95% CI, 0.167–0.846) for the development of CA-MRSA. The interaction between antibiotic exposure and age &lt; 3 was the most significant predictor of CA-MRSA (P = .019; 95% CI, 0.139–1.40).

CONCLUSIONS Prior antibiotic therapy in patients &lt; 3 years of age was associated with a significant risk of developing CA-MRSA. A comprehensive assessment of CA-MRSA patients should include objective methods of measuring prior antibiotic exposure such as pharmacy records.

Low-molecular-weight heparin use in special populations

Because many obese patients and patients with underlying renal dysfunction require surgical intervention, it is important to examine the dosage recommendations and monitoring required with low-molecular-weight heparins.

Vicia tetrasperma (four-seeded vetch) ingestion by a 3-year-old child

We report an ingestion of Vicia tetrasperma (four-seeded vetch), initially misidentified as crown vetch (Coronilla varia). Vicia tetrasperma is not listed in POISINDEX; little is known of its toxic effects and we found no published human case reports. The child suffered only minor gastrointestinal effects which lasted a few hours and had no residual effects upon 24- and 96-hour followups.

Integration of clinical and administrative strategies to reduce expenditures for antimicrobial agents

A comprehensive program of clinical and administrative strategies to reduce expenditures for antimicrobial agents is described. Clinical intervention strategies include the use of antimicrobial order sheets, standardized dosage regimens, restriction policies for certain antimicrobial agents, and position statements on the use of restricted agents. A cornerstone of the program is the support for cost-reduction interventions offered by the pharmacy and therapeutics committee and its subcommittee on therapeutics; that support is demonstrated through endorsement and enforcement of pharmacy programs. Physicians are reminded of the cost-reduction programs through periodic articles in the pharmacy newsletter and an "antibiogram" card supplied by the division of epidemiology. The effectiveness of these interventions has been demonstrated by progressive decreases in expenditures for antimicrobial agents during 1987 and 1988. Antimicrobial agents also account for increasingly smaller percentages of the total drug budget. This combination of clinical and administrative strategies reduced expenditures for antimicrobial agents by more than $700,000 over two years without the use of clinical specialists or any apparent sacrifice in the quality of patient care.

Penetrating neck injuries: experience with selective exploration

Although many authors have stated that surgical exploration should be mandatory for all neck wounds that penetrate the platysma, recent reports from many centers now claim that selective exploration is both safe and reasonable. A policy of selective exploration based on clinical presentation, anatomic location, and results of diagnostic studies has been followed at The Cooper Green Hospital in Birmingham, Alabama, for the past 13 years. We report a study of penetrating neck wounds in 136 consecutive patients admitted to The Cooper Green Hospital from 1972 to 1984. Seventy-seven patients (57%) had exploration immediately, with one death, while the remaining 59 (43%) were admitted and observed. Of these 59 patients, ten had arch aortography and nine had esophagography, all of which yielded normal results. The remainder of the patients observed had no clinical signs or symptoms to suggest a major injury. There were no deaths or complications related to the neck wounds in the 59 patients observed. Results of 27 explorations (35%) were negative. We conclude that selective exploration of penetrating neck wounds is both safe and reasonable.

Newer antihistamines and histamine-release inhibitors

Traditional H1 receptor antagonists are a mainstay of drug therapy for the allergic state, but cause numerous discomforting side effects which often hinder compliance. Newer H1 antagonists, including astemizole and terfenadine, appear remarkably free of central side effects and may provide a therapeutic breakthrough for clinicians. H2 antagonists have revolutionized drug therapy for hypersecretory states. Ranitidine appears to have fewer side effects than cimetidine at this stage in its utilization history, but has not been used as extensively. Other antisecretory agents of promise include some tricyclic antidepressants, prostaglandin derivatives, and potassium-hydrogen ATPase inhibitors. Newer histamine-release inhibitors (ketotifen, oxatimide e.g.) are effective orally and offer better patient compliance.

Cephalosporin-use restrictions in teaching hospitals

A survey of pharmacy directors in teaching hospitals was conducted in March 1983 to ascertain policies for management of cephalosporin use. Surveys were sent to 298 institutions in each of the United States except Alaska. Respondents were asked various questions regarding hospital policies on cephalosporin use. Responses were received from 179 hospitals that had formularies; 99 of these had formal restriction policies, more frequently for second- and third-generation agents than for first-generation agents, and 13 planned to institute restriction policies. In 68% of hospitals with restriction policies, restricted drugs were released only after consultation with the infectious disease service. Chart review was the most frequently reported method of monitoring use of restricted cephalosporins. Approximately 40% of respondents had therapeutic equivalence policies, and more than 40% had recently deleted one or more cephalosporins from the formulary. The percentage of hospitals with formal restriction policies (55%) was greater than in a 1979 survey (32%). Many teaching hospitals have initiated policies to curb rising drug costs associated with the use of cephalosporin antibiotics.

Restricted cephalosporin use in teaching hospitals

The approaches of teaching hospitals toward limiting the number of cephalosporin drug products on formularies were studied in a mail survey. Pharmacy department directors of 128 teaching hospitals with 200 beds or more responded to teh survey. Forty-two of 128 (33%) hospitals had established formal restriction policies (FRPs) for cephalosporins (CS). Cephalexin and cephradine were the predominant formulary oral CS. Few hospitals had established "therapeutic equivalents" policies, yet the majority of hospitals had a single oral CS on the formulary. Cefazolin was the predominant injectable CS on all formularies; cefamandole and cefoxitin were the predominant restricted CS. In hospitals without restriction policies, these newer CS were on the formulary in 55% of the cases; in FRP hospitals, the figure was 15%. The occurrence of a single, formulary, unrestricted CS was much more likely in FRP hospitals (38%) than in hospitals with no restriction policy (NRP) (8%). FRP hospitals tended to have fewer unrestricted formulary CS. Eighty-three percent of FRP hospitals and 41% of NRP hospitals monitored CS use.

The External Location of Phosphatase Activity in Phosphorus-Deficient Spirodela Oligorrhiza

Phosphorus deficiency (P deficiency) caused a 10-20�fold increase in phos-phatase activity of S. oligorrhiza homogenates. Specific staining showed that phosphatase in control plants was located primarily in and around the vascular strands, and in P�deficient plants it was located in the epidermis of the root and undersurface of the frond. Dissection experiments showed that roots of P�deficient plants contained a disproportionately high phosphatase activity. When plant and root homogenates were fractionated, phosphatase activity was recovered in the supernatant rather than in any cell particle fraction. However, intact plants released very little phosphatase to the external medium.