Deprescribing interventions in older adults: An overview of systematic reviews.

OBJECTIVE: The growing deprescribing field is challenged by a lack of consensus around evidence and knowledge gaps. The objective of this overview of systematic reviews was to summarize the review evidence for deprescribing interventions in older adults. METHODS: 11 databases were searched from 1st January 2005 to 16th March 2023 to identify systematic reviews. We summarized and synthesized the results in two steps. Step 1 summarized results reported by the included reviews (including meta-analyses). Step 2 involved a narrative synthesis of review results by outcome. Outcomes included medication-related outcomes (e.g., medication reduction, medication appropriateness) or twelve other outcomes (e.g., mortality, adverse events). We summarized outcomes according to subgroups (patient characteristics, intervention type and setting) when direct comparisons were available within the reviews. The quality of included reviews was assessed using A MeaSurement Tool to Assess systematic Reviews 2 (AMSTAR 2). RESULTS: We retrieved 3,228 unique citations and assessed 135 full-text articles for eligibility. Forty-eight reviews (encompassing 17 meta-analyses) were included. Thirty-one of the 48 reviews had a general deprescribing focus, 16 focused on specific medication classes or therapeutic categories and one included both. Twelve of 17 reviews meta-analyzed medication-related outcomes (33 outcomes: 25 favored the intervention, 7 found no difference, 1 favored the comparison). The narrative synthesis indicated that most interventions resulted in some evidence of medication reduction while for other outcomes we found primarily no evidence of an effect. Results were mixed for adverse events and few reviews reported adverse drug withdrawal events. Limited information was available for people with dementia, frailty and multimorbidity. All but one review scored low or critically low on quality assessment. CONCLUSION: Deprescribing interventions likely resulted in medication reduction but evidence on other outcomes, in particular relating to adverse events, or in vulnerable subgroups or settings was limited. Future research should focus on designing studies powered to examine harms, patient-reported outcomes, and effects on vulnerable subgroups. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42020178860.

Fake Xanax: Designer Emerging Benzodiazepine Epidemic Linked to Morbidity and Mortality a Narrative Review.

Etizolam is a thienodiazepine derivative which produces an anxiolytic effect similar to benzodiazepines such as alprazolam (Xanax). Like classic benzodiazepines, etizolam has a high affinity towards the GABAA receptor, and allosterically potentiates the effects of GABA resulting in neuronal hyperpolarization related to chloride influx. When taken in therapeutic doses, etizolam produces a similar effect to Xanax. Counterfeit Xanax tablets contain variable amounts of etizolam. Tablets with high amounts of etizolam can cause toxicity if ingested, especially when combined with other substances. When toxic symptoms occur in patients, they may include severe sedation, unconsciousness, and depression of the medullary respiratory center. In this regard, there is the potential for death. Additionally, the rise in fake Xanax tablets containing etizolam and other counterfeit medications has been exacerbated by the difference in regulations regarding these substances in different countries as well as the illegal drug trade. Healthcare providers may also play a role through the over- or underprescribing of certain medications. Thus, in order to combat the rise in counterfeit medications such as fake Xanax, international cooperation, regulation, and enforcement of laws pertaining to the manufacture, prescription, and distribution of these substances are needed.

Defects of renal tubular homeostasis and cystogenesis in the Pkhd1 knockout.

Loss of PKHD1-gene function causes autosomal recessive polycystic kidney disease (ARPKD) characterized by bilateral severely enlarged kidneys and congenital liver fibrosis requiring kidney replacement therapy most frequently during childhood. Studies using renal tissue from ARPKD patients suggest cyst promotion by suppressed hippo activity and enhanced Src/STAT3-signaling. We address renal homeostasis in female Pkhd1-knockout mice, aged 3 to 9 months, and observe features in common with late-onset ARPKD. Pkhd1-knockout animals show significant increase in kidney and liver weight with preserved organ function. Kidney cyst formation of the S3 segment is accompanied by macrophage recruitment and fibrotic remodeling. Cystic epithelia display increased proliferation, high levels of nuclear YAP/TAZ, and enhanced apoptosis. Y705-phosphorylated STAT3 is strongly enhanced in nuclei of cyst-lining epithelia. In this Pkhd1-deficiency model, stressed cystic epithelia expose the altered signaling pattern and disease-related mechanisms deemed relevant to human ARPKD, and thus may allow identification of therapeutic targets of this disease.

Out-of-Pocket Expenses for Long-Term Care by Dementia Status and Residential Setting among US Older Adults.

OBJECTIVE: To examine long-term care out-of-pocket payments by dementia status and residential setting. DESIGN: Compare monthly out-of-pocket long-term care expenses paid to facilities and helpers, total monthly out-of-pocket long-term expenses and as a percentage of monthly income by dementia status and residential status (community, residential facility, and nursing home). SETTING AND PARTICIPANTS: US Nationwide, 2019 National Health and Aging Trends Study (NHATS) respondents aged ≥70 years. METHODS: We analyzed respondent-level data from the nationally representative 2019 NHATS. Weighted descriptive statistics were calculated for long-term care payments by source and summarized by dementia status and the respondent's residential status. RESULTS: Among 4505 respondents aged ≥70 years, 1750 (38.8%) had possible or probable dementia and 2755 (61.2%) had no dementia. The median monthly out-of-pocket long-term care expenses for persons with dementia was $1465 for those living in nursing homes, and $2925 for those living in other residential facilities, much higher than those with dementia living in the community ($260). Although these are similar to the median out-of-pocket payments for persons without dementia by setting, those with dementia were at greater risk of facing catastrophic out-of-pocket expenses for long-term care than those without dementia, with the 75th percentile value of out-of-pocket payment at $4566 among dementia adults living in non-nursing home residential care facilities, and $7500 for those in nursing homes, compared to $3694 and $3100 among those without dementia. At median, these expenses accounted for 100% of monthly income of respondents with dementia living in facilities. CONCLUSIONS AND IMPLICATIONS: Persons with dementia living in facilities often face substantial financial burdens from high out-of-pocket long-term care expenses. Policies that provide sufficient financial assistance are needed to address long-term care-related financial burdens experienced by older adults and their families, especially for those with dementia.

Cervical cancer during the covid pandemic: Are patients presenting with more advanced or larger tumours?

OBJECTIVES: Concerns were raised by clinicians at the Oxford Gynaecological Cancer MDT that there was an increasing number of women presenting with large cervical tumours requiring chemo-radiotherapy, possibly due to delays associated with the COVID pandemic. This audit was undertaken to assess whether this was a real event. STUDY DESIGN: This retrospective cohort study collated the data from the central pathology service covering Oxfordshire, in the Oxford Gynaecological cancer centre. The control population consisted of patients treated during the 2 years pre-pandemic (1st Jan 2018-31 Dec 2019) and the study group the 2-year pandemic period (1st Jan 2020 until 31st December 2021). A total of 153 patients (74 control and 79 study) were diagnosed of cervical cancer during the study period. Variables included in the analysis were age, pathway of referral and diagnosis (cytology or clinical), FIGO stage, tumour histology, tumour size (using maximum diameter on MRI) and treatment. Student's t-test was used for continuous and discrete variables, respectively. The X2 test was used for the statistical analysis of proportions. RESULTS: There was no statistically significant differences was noted in the referral pathways during both periods. Statistically significant stage migration from FIGO stage II to III was detected (p < 0.05), though no statistically significant change in tumour size. However, the pattern of tumour volume on case-to-case comparison elicited more cases with larger volumes during the pandemic periods. CONCLUSIONS: Referral pathways of diagnosed cancer cervix was not affected during the pandemic in Oxfordshire. Therapeutic treatment numbers were unchanged - but some changes in tumour volume were likely the reason for the impression more such cases. Whether the stage shift noted here is representative of the wider population requires further studies.

Exclusive enteral nutrition: An optimal care pathway for use in children with active luminal Crohn's disease.

AIM: Exclusive enteral nutrition (EEN) is recommended as a first-line therapy for active luminal paediatric Crohn's disease, by many contemporary consensus guidelines. However, EEN protocols vary internationally. A key enabler for the use of EEN therapy has been identified as the standardisation of protocols. The aim of this study was to develop an optimal care pathway for use of EEN in children with active luminal Crohn's disease. METHODS: A working group of 11 paediatric gastroenterology dietitians and one paediatric gastroenterologist from Australia and New Zealand was convened to develop a standard optimal care pathway. Seven key areas were identified; clinical indications, workup assessments, EEN prescription, monitoring, food reintroduction, partial enteral nutrition and maintenance enteral nutrition. Recent literature was reviewed, assessed according to the National Health and Medical Research Council guidelines, and consensus statements were developed and voted on. Consensus opinion was used where literature gaps existed. RESULTS: A total of nineteen consensus statements from the seven key areas were agreed upon. The consensus statements informed the optimal care pathway for children with active luminal undertaking EEN in Australia and New Zealand. CONCLUSION: This study developed an EEN optimal care pathway to facilitate standardisation of clinical care for children with active luminal Crohn's disease, and hopefully improve clinical outcomes and identify areas for future research.

Exclusive enteral nutrition in children and adolescents with Crohn disease: Dietitian perspectives and practice.

AIM: In newly diagnosed paediatric Crohn disease, exclusive enteral nutrition (EEN) is recommended as a first-line treatment for remission induction. However, EEN protocols vary internationally. The development of best practice protocols may make it easier to make definitive conclusions about optimal EEN therapy, and may improve patient outcomes. This study aims to determine the variations in current dietitian EEN practice within Australia and New Zealand (NZ) to inform a common EEN protocol in the future, and to gather perspectives on the need for nutrition resources for patients with inflammatory bowel disease (IBD). METHODS: A questionnaire was created and emailed to paediatric dietitians working with gastroenterologists in public and private paediatric centres in Australia and NZ. Respondents were invited to provide details of their perspectives of EEN therapy and protocol details. RESULTS: Eighteen paediatric dietitians responded to the questionnaire, 10 from Australia and 8 from NZ. There was clear consensus between respondents on the duration of EEN being 6 and 8 weeks, the need for close dietitian supervision while on EEN, and the method of food reintroduction. There was lack of consensus between dietitians regarding permitted concomitant foods whilst on EEN. This study also determined a potential benchmarking relationship between IBD dietitian hours and numbers of patients on EEN per year in a centre. CONCLUSIONS: Paediatric dietitians in Australia and NZ are mostly aligned in their practice of EEN. Development of a standard EEN protocol, and patient IBD resources, will further align practice and allow for greater research possibilities.

Brain mitochondrial iron accumulates in Huntington's disease, mediates mitochondrial dysfunction, and can be removed pharmacologically.

Mitochondrial bioenergetic dysfunction is involved in neurodegeneration in Huntington's disease (HD). Iron is critical for normal mitochondrial bioenergetics but can also contribute to pathogenic oxidation. The accumulation of iron in the brain occurs in mouse models and in human HD. Yet the role of mitochondria-related iron dysregulation as a contributor to bioenergetic pathophysiology in HD is unclear. We demonstrate here that human HD and mouse model HD (12-week R6/2 and 12-month YAC128) brains accumulated mitochondrial iron and showed increased expression of iron uptake protein mitoferrin 2 and decreased iron-sulfur cluster synthesis protein frataxin. Mitochondria-enriched fractions from mouse HD brains had deficits in membrane potential and oxygen uptake and increased lipid peroxidation. In addition, the membrane-permeable iron-selective chelator deferiprone (1 µM) rescued these effects ex-vivo, whereas hydrophilic iron and copper chelators did not. A 10-day oral deferiprone treatment in 9-week R6/2 HD mice indicated that deferiprone removed mitochondrial iron, restored mitochondrial potentials, decreased lipid peroxidation, and improved motor endurance. Neonatal iron supplementation potentiates neurodegeneration in mouse models of HD by unknown mechanisms. We found that neonatal iron supplementation increased brain mitochondrial iron accumulation and potentiated markers of mitochondrial dysfunction in HD mice. Therefore, bi-directional manipulation of mitochondrial iron can potentiate and protect against markers of mouse HD. Our findings thus demonstrate the significance of iron as a mediator of mitochondrial dysfunction and injury in mouse models of human HD and suggest that targeting the iron-mitochondrial pathway may be protective.

Amyloid Precursor Protein Haploinsufficiency Preferentially Mediates Brain Iron Accumulation in Mice Transgenic for The Huntington's Disease Mutation.

BACKGROUND: Huntington's disease (HD) is an autosomal dominant disorder caused by a CAG expansion in the huntingtin gene that results in expression of mutant huntingtin protein. Iron accumulates in HD brain neurons. Amyloid precursor protein (APP) promotes neuronal iron export. However, the role of APP in brain iron accumulation in HD is unclear. OBJECTIVE: To determine the effects of APP insufficiency on HD in YAC128 mice. METHODS: We crossed APP hemizygous mice (APP+/-) with YAC128 mice that are transgenic (Tg) for human mutant huntingtin (hmHTT) to generate APP+/+ hmHTT-/-, APP+/- hmHTT-/-, APP+/+ hmHTT+/- and APP+/- hmHTT+/- progeny. Mice were evaluated for behavioral, biochemical and neuropathology HD outcomes at 2-12 months of age. RESULTS: APP heterozygosity decreased cortical APP 25% and 60% in non-Tg and Tg mice, respectively. Cerebral and striatal iron levels were increased by APP knockdown in Tg mice only. Nest-building behavior was decreased in Tg mice; APP knockdown decreased nest building in non-Tg but not Tg mice. Rota-rod endurance was decreased in Tg mice. APP+/- hHTT+/- mice demonstrated additional decreases in rota-rod endurance from 4-10 months of age. Tg mice had smaller striatal volumes and fewer striatal neurons but were not affected by APP knockdown. CONCLUSIONS: APP heterozygosity results in greater decreases of cortical APP in Tg versus non-Tg mice. Mutant huntingtin transgenic mice develop brain iron accumulation as a result of greater suppression of APP levels. Elevated brain iron in Tg mice was associated with a decline in motor endurance consistent with a disease promoting effect of iron in the YAC128 model of human HD.

Paving the way to a bioresorbable technology: Development of the absorb BRS program.

Bioresorbable scaffolds (BRS) combine attributes of the preceding generations of percutaneous coronary intervention (PCI) devices with new technologies to result in a novel therapy promoted as being the fourth generation of PCI. By providing mechanical support and drug elution to suppress restenosis, BRS initially function similarly to drug eluting stents. Thereafter, through their degradation, BRS undergo a decline in radial strength, allowing a gradual transition of mechanical function from the scaffold back to the artery in order to provide long term effectiveness similar to balloon angioplasty. The principles of operation of BRS, whether of polymeric or metallic composition, follow three phases of functionality reflective of differing physiological requirements over time: revascularization, restoration, and resorption. In this review, these three fundamental performance phases and the metrics for the nonclinical evaluation of BRS, including both bench and preclinical testing, are discussed. © 2016 Wiley Periodicals, Inc.

Neonatal Iron Supplementation Induces Striatal Atrophy in Female YAC128 Huntington's Disease Mice.

BACKGROUND: Dysregulation of iron homeostasis is implicated in the pathogenesis of Huntington's disease. We have previously shown that increased iron intake in R6/2 HD neonatal mice, but not adult R6/2 HD mice potentiates disease outcomes at 12-weeks of age corresponding to advanced HD [Redox Biol. 2015;4 : 363-74]. However, whether these findings extend to other HD models is unknown. In particular, it is unclear if increased neonatal iron intake can promote neurodegeneration in mouse HD models where disease onset is delayed to mid-adult life. OBJECTIVE: To determine if increased dietary iron intake in neonatal and adult life-stages potentiates HD in the slowly progressive YAC128 HD mouse model. METHODS: Female neonatal mice were supplemented daily from days 10-17 with 120µg/g body weight of carbonyl iron. Adult mice were provided diets containing low (50 ppm), medium (150 ppm) and high (500 ppm) iron concentrations from 2-months of age. HD progression was determined using behavioral, brain morphometric and biochemical approaches. RESULTS: Neonatal-iron supplemented YAC128 HD mice had significantly lower striatal volumes and striatal neuronal cell body volumes as compared to control HD mice at 1-year of age. Neonatal-iron supplementation of HD mice had no effect on rota-rod motor endurance and brain iron or glutathione status. Adult iron intake level had no effect on HD progression. YAC128 HD mice had altered peripheral responses to iron intake compared to iron-matched wild-type controls. CONCLUSIONS: Female YAC128 HD mice supplemented with nutritionally-relevant levels of iron as neonates demonstrate increased striatal degeneration 1-year later.

Technology limitations of BRS in bifurcations.

Recommended techniques for bifurcation stenting continue to be revised with specific attention to bioresorbable scaffolds (BRS). Optimal procedural success and long-term outcomes with BRS can perhaps be improved with careful attention to implantation techniques. Good vessel preparation is imperative for optimal expansion of the scaffold, and proper vessel sizing is necessary to ensure compliance with scaffold expansion limits and preservation of proper scaffold function. The European Bifurcation Club (EBC) recommends provisional stenting for the majority of bifurcation lesions: permanent metallic stents are sized according to the distal vessel diameter, with subsequent post-dilatation of the proximal vessel to ensure stent apposition in the proximal main vessel. Recent BRS-specific modifications to the EBC recommendation suggest that selecting the scaffold size based on the diameter of the proximal main vessel can mitigate the risk of overexpansion and potential strut fracture. Expansion of the BRS requires a thoughtful balance between the risk of malapposition associated with underdeployment and the risk of strut fracture due to overdeployment. Post-dilatation of scaffolds should be performed, always respecting the maximum expansion limit, to correct any potential scaffold malapposition and minimise flow disturbances. Finally, dual antiplatelet therapy plays an important role in BRS bifurcation treatment to avoid thromboembolic events.

Neonatal iron supplementation potentiates oxidative stress, energetic dysfunction and neurodegeneration in the R6/2 mouse model of Huntington's disease.

Huntington's disease (HD) is a progressive neurodegenerative disorder caused by a CAG repeat expansion that encodes a polyglutamine tract in huntingtin (htt) protein. Dysregulation of brain iron homeostasis, oxidative stress and neurodegeneration are consistent features of the HD phenotype. Therefore, environmental factors that exacerbate oxidative stress and iron dysregulation may potentiate HD. Iron supplementation in the human population is common during infant and adult-life stages. In this study, iron supplementation in neonatal HD mice resulted in deterioration of spontaneous motor running activity, elevated levels of brain lactate and oxidized glutathione consistent with increased energetic dysfunction and oxidative stress, and increased striatal and motor cortical neuronal atrophy, collectively demonstrating potentiation of the disease phenotype. Oxidative stress, energetic, and anatomic markers of degeneration were not affected in wild-type littermate iron-supplemented mice. Further, there was no effect of elevated iron intake on disease outcomes in adult HD mice. We have demonstrated an interaction between the mutant huntingtin gene and iron supplementation in neonatal HD mice. Findings indicate that elevated neonatal iron intake potentiates mouse HD and promotes oxidative stress and energetic dysfunction in brain. Neonatal-infant dietary iron intake level may be an environmental modifier of human HD.

Postnatal nutritional iron deficiency impairs dopaminergic-mediated synaptic plasticity in the CA1 area of the hippocampus.

OBJECTIVES: Developmental iron deficiency (ID) has been shown to put children at risk for compromised learning and memory capacity, and it has also been shown to impair hippocampus-dependent forms of memory as well as hippocampal synaptic transmission. Catecholamines are known to play a pivotal role in memory consolidation, and studies have demonstrated that perinatal ID alters dopaminergic systems in various brain areas. It is not known, however, whether perinatal ID impairs dopaminergic synaptic plasticity in learning and memory structures such as the hippocampus. The objective of the present study was to examine dopaminergic-mediated synaptic efficacy in the hippocampus of mice subjected to an ID or control (CN) diet. METHODS: The present study used electrophysiological brain slice methods to examine dopaminergic-mediated synaptic efficacy in the hippocampus of mice subjected to an ID or CN diet from postnatal day (P) P0 through P20. Hippocampal brain slices were prepared in young (P26-30) and adult animals (P60-64). Synaptic efficacy was measured in CA1 neurons by examining population spike amplitude. Slices were treated with the dopaminergic agonist SKF-38393. RESULTS: Slices obtained from young and adult CN mice exhibited a long-lasting increase in synaptic efficacy as the result of SKF-38393 perfusion while the young and adult ID slices showed little or no increase. DISCUSSION: The present study demonstrates that postnatal ID produces long-lasting impairments in dopaminergic-dependent synaptic plasticity in the hippocampus. These impairments may play a role in the learning and memory deficits known to result from ID.

Mechanical versus manual chest compression CPR under ground ambulance transport conditions.

BACKGROUND: Novel mechanical chest compression devices offer the possibility to transport cardiac arrest patients with ongoing CPR and might shorten significantly the time delay to post-resuscitation care. METHODS: We simulated an eight-minute cardiac resuscitation situation during ambulance transport using CPR training manikins. We compared teams consisting of two experienced resuscitators with the performance of a mechanical chest compression device (LUCAS). RESULTS: CPR-performance by two experienced resuscitators demonstrated ambivalent results. Whereas mean compression rate was within the recommended range (103/min, 95% CI: 93-113/min), mean compression depth was closely below the actually recommended compression depth of >5 cm (49.7 mm, 95% CI: 46.1-53.3mm). Nevertheless, only a mean of two thirds (67%) of all compressions were classified as manually correct (defined as sternal compression depth >5 cm). In contrast, the LUCAS device showed a constant and reliable CPR performance (99.96% correctly applied chest compressions correctly applied within the device programmed parameters, P = 0.0162) with almost no variance between the different sequences. CONCLUSION: The LUCAS CPR device represents a reliable alternative to manual CPR in a moving ambulance vehicle during emergency evacuation. Furthermore, it needs less human resources and is safer for the EMS personnel.

Small molecules efficiently direct endodermal differentiation of mouse and human embryonic stem cells.

An essential step for therapeutic and research applications of stem cells is the ability to differentiate them into specific cell types. Endodermal cell derivatives, including lung, liver, and pancreas, are of interest for regenerative medicine, but efforts to produce these cells have been met with only modest success. In a screen of 4000 compounds, two cell-permeable small molecules were indentified that direct differentiation of ESCs into the endodermal lineage. These compounds induce nearly 80% of ESCs to form definitive endoderm, a higher efficiency than that achieved by Activin A or Nodal, commonly used protein inducers of endoderm. The chemically induced endoderm expresses multiple endodermal markers, can participate in normal development when injected into developing embryos, and can form pancreatic progenitors. The application of small molecules to differentiate mouse and human ESCs into endoderm represents a step toward achieving a reproducible and efficient production of desired ESC derivatives.

A small molecule that directs differentiation of human ESCs into the pancreatic lineage.

Stepwise differentiation from embryonic stem cells (ESCs) to functional insulin-secreting beta cells will identify key steps in beta-cell development and may yet prove useful for transplantation therapy for diabetics. An essential step in this schema is the generation of pancreatic progenitors--cells that express Pdx1 and produce all the cell types of the pancreas. High-content chemical screening identified a small molecule, (-)-indolactam V, that induces differentiation of a substantial number of Pdx1-expressing cells from human ESCs. The Pdx1-expressing cells express other pancreatic markers and contribute to endocrine, exocrine and duct cells, in vitro and in vivo. Further analyses showed that (-)-indolactam V works specifically at one stage of pancreatic development, inducing pancreatic progenitors from definitive endoderm. This study describes a chemical screening platform to investigate human ESC differentiation and demonstrates the generation of a cell population that is a key milepost on the path to making beta cells.

A small molecule that binds Hedgehog and blocks its signaling in human cells.

Small-molecule inhibition of extracellular proteins that activate membrane receptors has proven to be extremely challenging. Diversity-oriented synthesis and small-molecule microarrays enabled the discovery of robotnikinin, a small molecule that binds the extracellular Sonic hedgehog (Shh) protein and blocks Shh signaling in cell lines, human primary keratinocytes and a synthetic model of human skin. Shh pathway activity is rescued by small-molecule agonists of Smoothened, which functions immediately downstream of the Shh receptor Patched.

Anticoagulant effects of low-molecular-weight heparins in healthy cats.

BACKGROUND: Low-molecular-weight heparin (LMWH) has potential benefit in cats at risk for thromboembolic disease. However, LMWH pharmacokinetics has not been characterized in the cat. Drug effect with LMWH may be evaluated with analysis of factor Xa inhibition (anti-Xa) or thromboelastography (TEG). HYPOTHESIS: Administration of LMWH at previously recommended dosages and schedules to healthy cats will result in inhibition of factor Xa and hypocoagulable TEG. ANIMALS: In vivo research with heparin was performed in 5 purpose-bred cats. METHODS: In a prospective study with randomized crossover design, heparin or placebo was administered. Treatments were unfractionated heparin (UFH), 250 IU/kg q6h; dalteparin, 100 IU/kg q12h; enoxaparin, 1 mg/kg q12h; or 0.9% saline, 0.25 mL/kg q6h. Each drug was administered for 5 consecutive days followed by a minimum washout of 14 days. Baseline and post-treatment analyses included anti-Xa, TEG, and prothrombin time/activated partial thromboplastin time. RESULTS: Mean anti-Xa activity 4 hours after enoxaparin (0.48 U/mL) approached the human therapeutic target (0.5-1.0 U/mL); however, mean trough anti-Xa activity was below detection limits. Mean anti-Xa activity 4 hours after dalteparin was lower, and only 1 cat attained therapeutic target at a single time point. Cats receiving UFH attained target anti-Xa activity and changes in TEG at trough and 4 hours. CONCLUSIONS: Cats have rapid absorption and elimination kinetics with LMWH therapy. On the basis of pharmacokinetic modeling, cats will require higher dosages and more frequent administration of LMWH to achieve human therapeutic anti-factor Xa activity of 0.5-1 U/mL. Peak anti-Xa activity is predicted at 2 hours after administration of LMWH.