Managing adverse effects and drug-drug interactions of antiplatelet agents

Phillyrin and its metabolites treat pulmonary embolism by targeting PLCβ3 to inhibit platelet activation

ETHNOPHARMACOLOGICAL RELEVANCE

Lian Qiao (LQ), the dried fruit of Forsythia suspensa (Thunb.) Vahl, is a well-documented traditional Chinese medicine known for its detoxifying and heat-clearing properties. Clinically, compounds containing LQ are widely used to treat thrombotic diseases, indicating that it may have antithrombotic effects. However, its exact mechanism of action remains unknown.

AIM OF THE STUDY

This study aimed to verify the antithrombotic effect of LQ and further explore the material basis and target mechanism of its antithrombotic effect using various biological methods.

MATERIALS AND METHODS

An epinephrine-collagen-thrombin-induced mouse model of acute pulmonary embolism (APE) was established to study the effects of LQ on thrombus development. A UPLC/Q/TOF-MS screening and identification system based on the inhibition of platelet aggregation and Ca2+ antagonism was established to determine the pharmacodynamic components of LQ that inhibit platelet activation. The inhibitory effect of active ingredients on platelet activation, and the determination of the target of their inhibitory effect on platelet activation have been studied using chemical proteomics. Furthermore, based on the structure and function of the target protein, a multidisciplinary approach was adopted to analyze the molecular mechanism of active ingredient binding to target proteins and to evaluate the effects of active ingredients on the downstream signaling pathways of target proteins.

RESULTS

LQ showed significant anticoagulant effects in APE model mice. Phillyrin and phillygenin were the antiplatelet-activating components of LQ. PLCβ3 was identified as a target for inhibiting platelet activation by phillyrin and its metabolites. The mechanism underlying the effect involves phillyrin and its metabolites inhibiting PLCβ3 activity by blocking the binding of PLCβ3 to Gαq through non-covalently targeting the ASN260 of PLCβ3, thus inhibiting the downstream Gαq-PLCβ3-Ca2+ signaling pathway, effectively hindering platelet activation and therefore playing an anticoagulant role.

CONCLUSION

This study not only proposes and validates the antithrombotic effect of LQ for the first time but also finds that phillyrin and phillygenin are the main pharmacological substances through which LQ exerts antithrombotic activity and reveals a novel mechanism by which they exert antiplatelet activity by directly targeting and inhibiting PLCβ3 activity. These findings significantly contribute to our understanding of the therapeutic potential of phillyrin and provide important clues for the discovery and development of new antiplatelet drugs.

Polypharmacy and Guideline-Directed Medical Therapy Initiation Among Adults Hospitalized With Heart Failure

Background

Underprescribing of guideline-directed medical therapy (GDMT) for heart failure (HF) persists.

Objectives

The purpose of this study was to assess polypharmacy as a barrier to GDMT.

Methods

We examined participants hospitalized for HF with reduced ejection fraction and HF with mildly reduced ejection fraction between 2003 and 2017 from the Reasons for Geographic and Racial Differences in Stroke study. Participants were stratified by admission medication count-0 to 4, 5 to 9, and ≥10 medications. We examined GDMT use at admission, GDMT contraindications, and initiation of eligible indicated GDMT by medication count. We conducted a multivariable Poisson regression with robust standard errors to examine the association between medication count and GDMT initiation. GDMT included agents for HF with reduced ejection fraction/HF with mildly reduced ejection fraction, antiplatelet agents and statins for coronary artery disease, and anticoagulants for atrial fibrillation.

Results

Among 545 participants with HF, 34% were not taking a beta-blocker, 39% were not taking an angiotensin-converting enzyme inhibitor/angiotensin receptor blocker/angiotensin receptor-neprilysin inhibitor, or hydralazine-isosorbide dinitrate, and 90% were not taking a mineralocorticoid receptor antagonist at admission; among participants with coronary artery disease, 36% were not taking an antiplatelet agent, and 38% were not taking a statin; and among participants with atrial fibrillation, 49% were not taking an anticoagulant. Polypharmacy was inversely associated with initiation of at least one indicated medication (5-9 medications: relative risk [RR]: 0.67; 95% CI: 0.56-0.82; P < 0.001; ≥10 medications: RR: 0.50; 95% CI: 0.39-0.64; P < 0.001) and initiation of at least half of indicated medications (5-9 medications: RR: 0.64; 95% CI: 0.51-0.81; P < 0.001; ≥10 medications: RR: 0.50; 95% CI: 0.38-0.67; P < 0.001).

Conclusions

Polypharmacy is an important barrier to GDMT.

Comparative efficacy and safety of traditional Chinese medicine injections in patients with transient ischemic attack: A systematic review and network meta-analysis

OBJECTIVES

Traditional Chinese medicine (TCM) injections are extensively utilized for the treatment of transient ischemic attack (TIA). However, it remains unclear which specific TCM injection exhibits superior efficacy. In this study, we conducted a network meta-analysis to compare the clinical efficacy and safety of various TCM injections in the treatment of TIA, with the aim of identifying the optimal treatment regimen.

DESIGN

We searched seven databases to collect information on nine TCM injections for the treatment of transient randomized controlled trials (RCTs) for the treatment of transient ischemic attacks were collected from the establishment to August 2023. The methodological quality and risk of bias were assessed using the RoB 2.0 evaluation tool, and reticulated Meta-analysis was performed using R software and Stata software.

RESULTS

We ultimately included 58 RCTs involving 5502 patients and comprising 9 TCM injections. In terms of improving the total effective rate, Shuxuetong injection (P-score = 0.69) was the most effective. In addition, Shuxuetong injection was most effective in lowering total cholesterol (P-score = 1.00) and triglyceride (P-score = 1.00) levels. Notably, Shuxuetong injection remained the most prominent in reducing fibrinogen (P-score = 0.91). However, among other blood hemorheology indicators, Dengzhanhuasu injection was the best regimen in reducing plasma viscosity (P-score = 1.00), whole blood viscosity (high shear rate) (P-score = 0.87), and whole blood viscosity (low shear rate) (P-score = 0.90). It was found that Yinxingyetiquwu injection (P-score = 0.72) was the most effective in reducing the incidence of cerebral infarction. In terms of safety, 22 studies reported adverse effects and descriptive analyses showed that the number of adverse effects of combination therapy was comparable to that of conventional therapy and that the safety profile was good.

CONCLUSIONS

TCM injections in combination with CT may be a safe and effective intervention for patients with TIA, of which Shuxuetong injection, Dengzhanhuasu injection, and Yinxingyetiquwu injection may be more noteworthy. The quality of the literature included in the study was low, so further validation is needed with larger sample sizes, higher quality, and more rigorously designed RCTs.

SYSTEMATIC REVIEW REGISTRATION

[PROSPERO], identifier [CRD42023443652].

Individualized antiplatelet therapy for non-cardiogenic ischemic stroke

OBJECTIVE

This research aims to investigate the impact of individualized antiplatelet therapy guided by thromboelastography with platelet mapping (TEG-PM) on the clinical outcomes of patients with non-cardiogenic ischemic stroke.

METHODS

Among a total of 1264 patients, 684 individuals diagnosed with non-cardiogenic ischemic stroke underwent TEG-PM testing. Based on the adjustment of antiplatelet medication, these patients were divided into individual and control groups. Within the individual group, in accordance with the TEG-PM test results, a Maximum amplitude (MA) value greater than 47mm was defined as high residual platelet reactivity (HRPR), while an MA value less than 31mm was defined as low residual platelet reactivity (LRPR). Patients with arachidonic acid (AA) less than 50% and adenosine diphosphate (ADP) less than 30% were classified as aspirin-resistant or clopidogrel-resistant. Treatment strategies for antiplatelet medication were subsequently adjusted accordingly, encompassing increment, decrement, or replacement of drugs. Meanwhile, the control group maintained their original medication regimen without alterations.

RESULTS

The individual group included 487 patients, while the control group had 197. In the individual group, approximately 175 patients (35.9%) were treated with increased medication dosages, 89 patients (18.3%) with reduced dosages, and 223 patients (45.8%) switched medications. The results showed that the incidence rate of ischemic events in the individual group was lower than that of the control group (5.54% vs. 12.6%, P = 0.001), but no significant difference was observed in bleeding events. Cox regression analysis revealed age (hazard ratio, 1.043; 95% CI, 1.01-1.078; P = 0.011) and coronary heart disease (hazard ratio, 1.902; 95% CI, 1.147-3.153; P = 0.013) as significant risk factors for adverse events.

CONCLUSION

Individualized antiplatelet therapy based on TEG-PM results can reduce the risk of ischemic events in patients with non-cardiogenic ischemic stroke without increasing the risk of bleeding events or mortality. Advanced age and coronary heart disease were identified as risk factors affecting the outcomes of individualized antiplatelet therapy.

Pairwise synthetic cytotoxicity between Paxlovid and 100 frequently prescribed FDA-approved small molecule drugs on liver cells

Paxlovid is a recent FDA approved specific drug for COVID-19. Extensive prescription of Paxlovid could induce potential synthetic cytotoxicity with drugs. Herein, we aimed to examine pairwise synthetic cytotoxicity between Paxlovid and 100 frequently FDA approved small molecule drugs. Liver cell line HL-7702 or L02 was adopted to evaluate synthetic cytotoxicity between Paxlovid and the 100 small molecule drugs. Inhibitory concentration IC-10 and IC-50 doses for all the 100 small molecule drugs and Paxlovid were experimentally acquired. Then, pairwise synthetic cytotoxicity was examined with the fixed dose IC-10 for each drug. The most 4 significant interactive pairs (2 positively interactive and 2 negatively interactive) were further subjected to molecular docking simulation to reveal the structural modulation with Caspase-8, a key mediator for cell apoptosis.

Antiplatelet agents for the treatment of adults with COVID-19

BACKGROUND

Severe coronavirus disease 2019 (COVID-19) can cause thrombotic events that lead to severe complications or death. Antiplatelet agents, such as acetylsalicylic acid, have been shown to effectively reduce thrombotic events in other diseases: they could influence the course of COVID-19 in general.

OBJECTIVES

To assess the efficacy and safety of antiplatelets given with standard care compared to no treatment or standard care (with/without placebo) for adults with COVID-19.

SEARCH METHODS

We searched the Cochrane COVID-19 Study Register (which comprises MEDLINE (PubMed), Embase, ClinicalTrials.gov, WHO ICTRP, medRxiv, CENTRAL), Web of Science, WHO COVID-19 Global literature on coronavirus disease and the Epistemonikos COVID-19 L*OVE Platform to identify completed and ongoing studies without language restrictions to December 2022.

SELECTION CRITERIA

We followed standard Cochrane methodology. We included randomised controlled trials (RCTs) evaluating antiplatelet agents for the treatment of COVID-19 in adults with COVID-19, irrespective of disease severity, gender or ethnicity.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methodology. To assess bias in included studies, we used the Cochrane risk of bias tool (RoB 2) for RCTs. We rated the certainty of evidence using the GRADE approach for the outcomes.

MAIN RESULTS

Antiplatelets plus standard care versus standard care (with/without placebo) Adults with a confirmed diagnosis of moderate to severe COVID-19 We included four studies (17,541 participants) that recruited hospitalised people with a confirmed diagnosis of moderate to severe COVID-19. A total of 8964 participants were analysed in the antiplatelet arm (either with cyclooxygenase inhibitors or P2Y12 inhibitors) and 8577 participants in the control arm. Most people were older than 50 years and had comorbidities such as hypertension, lung disease or diabetes. The studies were conducted in high- to lower middle-income countries prior to wide-scale vaccination programmes. Antiplatelets compared to standard care: - probably result in little to no difference in 28-day mortality (risk ratio (RR) 0.95, 95% confidence interval (CI) 0.85 to 1.05; 3 studies, 17,249 participants; moderate-certainty evidence). In absolute terms, this means that for every 177 deaths per 1000 people not receiving antiplatelets, there were 168 deaths per 1000 people who did receive the intervention (95% CI 151 to 186 per 1000 people); - probably result in little to no difference in worsening (new need for invasive mechanical ventilation or death up to day 28) (RR 0.95, 95% CI 0.90 to 1.01; 2 studies, 15,266 participants; moderate-certainty evidence); - probably result in little to no difference in improvement (participants discharged alive up to day 28) (RR 1.00, 95% CI 0.96 to 1.04; 2 studies, 15,454 participants; moderate-certainty evidence); - probably result in a slight reduction of thrombotic events at longest follow-up (RR 0.90, 95% CI 0.80 to 1.02; 4 studies, 17,518 participants; moderate-certainty evidence); - may result in a slight increase in serious adverse events at longest follow-up (Peto odds ratio (OR) 1.57, 95% CI 0.48 to 5.14; 1 study, 1815 participants; low-certainty evidence), but non-serious adverse events during study treatment were not reported; - probably increase the occurrence of major bleeding events at longest follow-up (Peto OR 1.68, 95% CI 1.29 to 2.19; 4 studies, 17,527 participants; moderate-certainty evidence). Adults with a confirmed diagnosis of asymptomatic SARS-CoV-2 infection or mild COVID-19 We included two RCTs allocating participants, of whom 4209 had confirmed mild COVID-19 and were not hospitalised. A total of 2109 participants were analysed in the antiplatelet arm (treated with acetylsalicylic acid) and 2100 participants in the control arm. No study included people with asymptomatic SARS-CoV-2 infection. Antiplatelets compared to standard care: - may result in little to no difference in all-cause mortality at day 45 (Peto OR 1.00, 95% CI 0.45 to 2.22; 2 studies, 4209 participants; low-certainty evidence); - may slightly decrease the incidence of new thrombotic events up to day 45 (Peto OR 0.37, 95% CI 0.09 to 1.46; 2 studies, 4209 participants; low-certainty evidence); - may make little or no difference to the incidence of serious adverse events up to day 45 (Peto OR 1.00, 95% CI 0.60 to 1.64; 1 study, 3881 participants; low-certainty evidence), but non-serious adverse events were not reported. The evidence is very uncertain about the effect of antiplatelets on the following outcomes (compared to standard care plus placebo): - admission to hospital or death up to day 45 (Peto OR 0.79, 95% CI 0.57 to 1.10; 2 studies, 4209 participants; very low-certainty evidence); - major bleeding events up to longest follow-up (no event occurred in 328 participants; very low-certainty evidence). Quality of life and adverse events during study treatment were not reported.

AUTHORS' CONCLUSIONS

In people with confirmed or suspected COVID-19 and moderate to severe disease, we found moderate-certainty evidence that antiplatelets probably result in little to no difference in 28-day mortality, clinical worsening or improvement, but probably result in a slight reduction in thrombotic events. They probably increase the occurrence of major bleeding events. Low-certainty evidence suggests that antiplatelets may result in a slight increase in serious adverse events. In people with confirmed COVID-19 and mild symptoms, we found low-certainty evidence that antiplatelets may result in little to no difference in 45-day mortality and serious adverse events, and may slightly reduce thrombotic events. The effects on the combined outcome admission to hospital or death up to day 45 and major bleeding events are very uncertain. Quality of life was not reported. Included studies were conducted in high- to lower middle-income settings using antiplatelets prior to vaccination roll-outs. We identified a lack of evidence concerning quality of life assessments, adverse events and people with asymptomatic infection. The 14 ongoing and three completed, unpublished RCTs that we identified in trial registries address similar settings and research questions as in the current body of evidence. We expect to incorporate the findings of these studies in future versions of this review.

Prevalence and Clinical Significance of Drug-Drug and Drug-Dietary Supplement Interactions among Patients Admitted for Cardiothoracic Surgery in Greece

Background: Drug interactions represent a major issue in clinical settings, especially for critically ill patients such as those with cardiovascular disease (CVD) who require cardiothoracic surgery (CTS) and receive a high number of different medications. Methods: A cross-sectional study aimed at evaluating the exposure and clinical significance of drug–drug (DDIs) and drug–dietary supplement interactions (DDSIs) in patients admitted for CTS in the University Hospital of Crete Greece. DDIs were evaluated regarding underlying pharmacological mechanisms upon admission, preoperation, postoperation, and discharge from CTS clinic. Additionally, upon admission, the use of dietary supplements (DSs) and if patients had informed their treating physician that they were using these were recorded with subsequent analysis of potential DDSIs with prescribed medications. Results: The study employed 76 patients who were admitted for CTS and accepted to participate. Overall, 166 unique DDIs were identified, with 32% of them being related to pharmacokinetic (PK) processes and the rest (68%) were related to possible alterations of pharmacodynamic (PD) action. CVD medications and drugs for central nervous system disorders were the most frequently interacting medications. In total, 12% of the identified DDIs were of serious clinical significance. The frequency of PK-DDIs was higher during admission and discharge, whereas PD-DDIs were mainly recorded during pre- and postoperation periods. Regarding DS usage, 60% of patients were using DSs and perceived them as safe, and the majority had not informed their treating physician of this or sought out medical advice. Analysis of medical records showed 30 potential combinations with prescribed medications that could lead in DDSIs due to modulation of PK or PD processes, and grapefruit juice consumption was involved in 38% of them. Conclusions: An increased burden of DDIs and DDSIs was identified mostly upon admission for patients in CTS clinics in Greece. Healthcare providers, especially prescribing physicians in Greece, should always take into consideration the possibility of DDIs and the likely use of DS products by patients to promote their well-being; this should only be undertaken after receiving medical advice and an evidenced-based evaluation.

Clopidogrel Drug Interactions and Serious Bleeding: Generating Real-World Evidence via Automated High-Throughput Pharmacoepidemiologic Screening

Few population-based studies have examined bleeding associated with clopidogrel drug-drug interactions (DDIs). We sought to identify precipitant drugs taken concomitantly with clopidogrel (an object drug) that increased serious bleeding rates. We screened 2000-2015 Optum commercial health insurance claims to identify DDI signals. We performed self-controlled case series studies for clopidogrel plus precipitant pairs, examining associations with gastrointestinal bleeding or intracranial hemorrhage. To distinguish native bleeding effects of a precipitant, we reexamined associations using pravastatin as a negative control object drug. Among 431 analyses, 28 clopidogrel plus precipitant pairs were statistically significantly positively associated with serious bleeding. Ratios of rate ratios ranged from 1.13-3.94. Among these pairs, 13 were expected given precipitant drugs alone increased and/or were harbingers of serious bleeding. The remaining 15 pairs constituted new DDI signals, none of which are currently listed in two major DDI knowledge bases.

Changes in Treatment Patterns and Incremental Health Care Utilization Due to P2Y12-Associated Complications in Patients with Acute Coronary Syndrome

BACKGROUND

P2Y12 antiplatelet therapy (APT) is highly efficacious in reducing the incidence of ischemic events in patients with acute coronary syndrome (ACS); however, it is associated with several adverse complications. Data on P2Y12-associated complications and adherence to APT are sparse.

OBJECTIVE

To describe the characteristics, frequency of P2Y12-associated complications, adherence and persistence to P2Y12 APT, and health care utilization among ACS patients on P2Y12 APT.

METHODS

This retrospective observational study of the MarketScan Commercial Claims and Encounters Database identified patients aged ≥ 18 years who were discharged from an ACS hospitalization in 2012-2014 and initiated P2Y12 APT (ticagrelor, prasugrel, or clopidogrel). The proportion of patients within each treatment group who experienced P2Y12-associated complications within 1 year and who were adherent to APT were determined. Frequencies of all-cause health care utilization (i.e., hospitalization, length of stay, emergency room [ER] visits, outpatient visits, cardiac events, and transfusions) were evaluated for each treatment group. Poisson regressions were conducted to evaluate the association between nonad-herence with P2Y12 APT and health care utilization, after adjusting for demographics (age and gender), health insurance type, and comorbidities.

RESULTS

Among 11,629 ACS patients, most were male; 44.6% had hypertension; 20.6% had diabetes; and 53.4% had hyperlipidemia. Clopidogrel use was common (62.6%), with ticagrelor use less common (9.0%). Among all groups, approximately one third experienced P2Y12-associated complications. One-year adherence to APT was suboptimal (68% overall), with 73.3% adherence among prasugrel users, followed by 71.4% adherence among ticagrelor users and 65.6% adherence among clopidogrel users. Switching was most common with ticagrelor users. Inpatient hospitalizations, cardiac events, and transfusions were more common in clopidogrel users compared with prasugrel and ticagrelor users. Nonadherent patients experienced significantly more hospitalizations, ER visits, and transfusions (1.34, 1.09, and 1.85 [P < 0.05], respectively) compared with adherent patients. These trends of association remained consistent across all treatment groups. Also, patients not adherent to ticagrelor experienced 1.9 times as many cardiac events as adherent patients. However, this association was not significant for clopidogrel and prasugrel users. Patients not adherent to P2Y12 APT experienced significantly lower outpatient visits compared with adherent patients.

CONCLUSIONS

Complications associated with P2Y12 in ACS patients treated with P2Y12 APT were common, with dyspnea, heart block, and major or life-threatening bleeding as the most common. Adherence was significantly associated with lower health care utilization. Increased adherence to secondary prevention therapy among these very high-risk patients is crucial. Disease management strategies to improve adherence and reduce treatment-associated adverse events through individualized patient care, alternative secondary treatment options, and physician awareness should be designed, implemented, and sustained.

DISCLOSURES

Data analysis was conducted by Merck & Co., the manufacturer of vorapaxar (ZONTIVITY). At the time of this study, Vyas was an employee of Rutgers University, which received grant funding from Merck & Co. for this study, and is now employed with the University of Rhode Island. Patel was employed by Symphony Solutions and the University of North Carolina during the drafting and revising of the manuscript. Bash is employed by Merck & Co. Simpson received consulting fees from Merck & Co. for work on this study and has received fees for research from Amgen and Pfizer. Study concept and design were contributed by Vyas, Bash, Patel, and Simpson. Patel took the lead in data collection, assisted by the other authors. All the authors contributed equally to data analysis and manuscript preparation. The abstract for this study was presented as a poster at the American Heart Association Scientific Sessions 2016; November 12-16, 2016; New Orleans, Louisiana.

Uncertain Associations of Major Bleeding and Concurrent Use of Antiplatelet Agents and Chinese Medications: A Nested Case-Crossover Study

Despite the evidence that some commonly used Chinese medications (CMs) have antiplatelet/anticoagulant effects, many patients still used antiplatelets combined with CMs. We conducted a nested case-crossover study to examine the associations between the concomitant use of antiplatelets and CMs and major bleeding using population-based health database in Taiwan. Among the cohort of 79,463 outpatients prescribed antiplatelets (e.g., aspirin and clopidogrel) continuously, 1,209 patients hospitalized with new occurring bleeding in 2012 and 2013 were included. Those recruited patients served as their own controls to compare different times of exposure to prespecified CMs (e.g., Asian ginseng and dong quai) and antiplatelet agents. The periods of case, control 1, and control 2 were defined as 1–4 weeks, 6–9 weeks, and 13–16 weeks before hospitalization, respectively. Conditional logistic regression analyses found that concurrent use of antiplatelet drugs with any of the prespecified CMs in the case period might not significantly increase the risks of bleeding over that in the control periods (OR = 1.00, 95% CI 0.51 to 1.95 and OR = 1.13, 95% CI 0.65 to 1.97). The study showed no strong relationships between hospitalization for major bleeding events and concurrent use of antiplatelet drugs with the prespecified CMs.

Drug-drug interactions in a cohort of hospitalized elderly patients

PURPOSE

The aim of this study is to assess the prevalence of patients exposed to potentially severe drug-drug interactions (DDIs) at hospital admission and discharge and the related risk of in-hospital mortality and adverse clinical events, readmission, and all-cause mortality at 3 months.

METHODS

This cross-sectional, prospective study was held in 70 Italian internal medicine and geriatric wards. Potentially severe DDIs at hospital admission and discharge; risk of in-hospital mortality and of adverse clinical events, readmission, and all-cause mortality at 3-month follow-up.

RESULTS

Among 2712 patients aged 65 years or older recruited at hospital admission, 1642 (60.5%) were exposed to at least one potential DDI and 512 (18.9%) to at least one potentially severe DDI. Among 2314 patients discharged, 1598 (69.1%) were exposed to at least one potential DDI and 1561 (24.2%) to at least one potentially severe DDI. Multivariate analysis found a significant association with an increased risk of mortality at 3 months in patients exposed to at least two potentially severe DDIs (Odds ratio 2.62; 95% confidence interval, 1.00-6.68; p = 0.05). Adverse clinical events were potentially related to severe DDIs in two patients who died in the hospital, in five readmitted, and one who died at 3 months after discharge.

CONCLUSIONS

Hospitalization was associated with an increase in potentially severe DDIs. A significant association was found for mortality at 3 months after discharge in patients with at least two potentially severe DDIs. Careful monitoring for potentially severe DDIs, especially those created at discharge or recently generated, is important to minimize the risk of harm.

Adverse drug events as a cause of hospitalization in older adults

Older adults are about four to seven times more likely than younger persons to experience adverse drug events (ADEs) that cause hospitalization, especially if they are women and take multiple medications. The prevalence of drug-related hospitalizations has been reported to be as high as 31%, with large heterogeneity between different studies, depending on study setting (all hospital admissions or only acute hospital admissions), study population (entire hospital, specific wards, selected population and/or age groups), type of drug-related problem measured (adverse drug reaction or ADE), method of data collection (chart review, spontaneous reporting or database research) and method and definition used to detect ADEs. The higher risk of drug-related hospitalizations in older adults is mainly caused by age-related pharmacokinetic and pharmacodynamic changes, a higher number of chronic conditions and polypharmacy, which is often associated with the use of potentially inappropriate drugs. Other factors that have been involved are errors related to prescription or administration of drugs, medication non-adherence and inadequate monitoring of pharmacological therapies. A few commonly used drugs are responsible for the majority of emergency hospitalizations in older subjects, i.e. warfarin, oral antiplatelet agents, insulin and oral hypoglycaemic agents, central nervous system agents. The aims of the present review are to summarize recent evidence concerning drug-related hospitalization in older adults, to assess the contribution of specific medications, and to identify potential interventions able to reduce the occurrence of these drug-related events, as they are, at least partly, potentially preventable.

Flexible, transparent, and noncytotoxic graphene electric field stimulator for effective cerebral blood volume enhancement

Enhancing cerebral blood volume (CBV) of a targeted area without causing side effects is a primary strategy for treating cerebral hypoperfusion. Here, we report a new nonpharmaceutical and nonvascular surgical method to increase CBV. A flexible, transparent, and skin-like biocompatible graphene electrical field stimulator was placed directly onto the cortical brain, and a noncontact electric field was applied at a specific local blood vessel. Effective CBV increases in the blood vessels of mouse brains were directly observed from in vivo optical recordings of intrinsic signal imaging. The CBV was significantly increased in arteries of the stimulated area, but neither tissue damage nor unnecessary neuronal activation was observed. No transient hypoxia was observed. This technique provides a new method to treat cerebral blood circulation deficiencies at local vessels and can be applied to brain regeneration and rehabilitation.

Therapeutic effects of water soluble danshen extracts on atherosclerosis

Danshen is a traditional Chinese medicine with many beneficial effects on cardiovascular diseases. The aim of this study was to evaluate the mechanisms responsible for the antiatherogenic effect of water soluble Danshen extracts (DEs). Rat vascular smooth muscle cells (VSMCs) and human umbilical vein endothelial cells (HUVECs) were treated with DE. To evaluate the effects of DE in vivo, carotid balloon injury and tail vein thrombosis were induced in Sprague-Dawley (SD) rats and iliac artery stent was induced in New Zealand white rabbits. The inhibitory action of DE on platelet aggregation was confirmed with an impedance aggregometer. DE inhibited the production of reactive oxygen species, and the migration and proliferation of platelet-derived growth factor-BB stimulated VSMCs. Furthermore, DE prevented inflammation and apoptosis in HUVECs. Both effects of DE were reconfirmed in both rat models. DE treatment attenuated platelet aggregation in both in vivo and ex vivo conditions. Pretreatment with DE prevented tail vein thrombosis, which is normally induced by κ-carrageenan injection. Lastly, DE-treated rabbits showed decreased in-stent restenosis of stented iliac arteries. These results suggest that water soluble DE modulates key atherogenic events in VSMCs, endothelial cells, and platelets in both in vitro and in vivo conditions.

Aortic thrombosis in dogs: presentation, therapy, and outcome in 26 cases

OBJECTIVES

The pathogenesis and presentation of aortic thrombosis (AT) in dogs is not well characterized and an effective antithrombotic therapy for AT in dogs has not been identified. Our goal is to report the clinical presentation and results of therapies in dogs with AT.

ANIMALS

Twenty-six client-owned dogs.

METHODS

Retrospective review of medical records of dogs diagnosed with AT between 2003 and 2010.

RESULTS

Twenty-six dogs had an apparent primary mural aortic thrombus. None had structural heart disease at diagnosis. Twenty dogs were ambulatory with varying degrees of pelvic limb dysfunction. Duration of ambulatory dysfunction was 7.8 weeks (range 1 day-52 weeks). A majority of dogs (58%) had no concurrent conditions at diagnosis. Fourteen dogs were treated with a standard warfarin protocol for a median period of 22.9 months (range 0.5-53 months). Ambulatory function improved in all dogs treated with warfarin. Time until clinical improvement was 13.9 days (range 2-49 days). Dogs treated with warfarin did not become non-ambulatory, die or undergo euthanasia related to AT, or have a known serious hemorrhagic event.

CONCLUSIONS

The pathogenesis of AT in dogs is distinct from that of aortic thromboembolism (ATE) in cats. Aortic thrombosis in dogs is more likely to involve local thrombosis in the distal aorta with embolization to the arteries of the pelvic limb resulting in chronic progressive ambulatory dysfunction. Chronic warfarin administration is well-tolerated and appears to be an effective short-term and long-term therapy for dogs with AT.

Hemorrhagic complications after prasugrel (Effient) therapy for vascular neurointerventional procedures

INTRODUCTION

Dual antiplatelet therapy (DAPT) with aspirin and a thienopyridine (eg, clopidogrel) prevents stent related thromboembolic events in cardiac patients and is frequently utilized during neurointerventional surgery. However, recent data suggest that many patients exhibit clopidogrel resistance. Prasugrel-a newer thienopyridine-lowers the rate of cardiac stent thromboses in clopidogrel non-responders but a paucity of data exist regarding its safety and efficacy in neurointerventional surgery.

METHODS

All patients undergoing neurointerventional surgery by a single interventionalist (CJM) over a 20 month period were retrospectively identified. Charts were reviewed for pre- and post-procedural DAPT regimens, pre-procedural coagulation parameters and procedural complications.

RESULTS

76 patients received pre- and post-procedural DAPT for endovascular treatment of an intracerebral aneurysm, dural arteriovenous fistula or intra/extracranial arterial stenosis. 51 patients underwent 55 total procedures and were treated with aspirin/clopidogrel; 25 patients underwent 31 total procedures and were treated with aspirin/prasugrel. Those patients who received aspirin/prasugrel DAPT were identified pre-procedurally to be clopidogrel non-responders. Both treatment groups had a similar percentage of patients undergoing aneurysm coiling, stent assisted aneurysm coiling, aneurysm Onyx embolization, aneurysm pipeline embolization device treatment, extra/intracranial carotid artery angioplasty and stenting, and dural arteriovenous fistula coil embolization. A total of eight (9.3%) hemorrhagic complications were observed, two (3.6%) in the aspirin/clopidogrel group and six (19.4%) in the aspirin/prasugrel group (p=0.02). No differences were noted in hemorrhage rates for each procedure between treatment groups, nor were there any differences in thrombotic complications between groups.

CONCLUSION

Our results suggest that DAPT with aspirin/prasugrel may predispose to a higher risk of hemorrhage during neurointerventional surgery compared with DAPT with aspirin/clopidogrel.

Polypharmacy and food-drug interactions among older persons: a review

Polypharmacy is generally defined as the use of 5 or more prescription medications on a regular basis. The average number of prescribed and over-the-counter medications used by community-dwelling older adults per day in the United States is 6 medications, and the number used by institutionalized older persons is 9 medications. Almost all medications affect nutriture, either directly or indirectly, and nutriture affects drug disposition and effect. This review will highlight the issues surrounding polypharmacy, food-drug interactions, and the consequences of these interactions for the older adult.