Thiazolidinediones and cardiovascular risk - a question of balance

Beyond Blood Sugar: Investigating the Cardiovascular Effects of Antidiabetic Drugs

Cardiovascular disease is a major comorbidity associated with diabetes mellitus. Various antidiabetic drugs are currently used to treat type 2 diabetes mellitus and have varying effects on the cardiovascular system. Some drugs, such as glucagon-like peptide 1 (GLP-1) agonists and sodium-glucose cotransporter 2 (SGLT-2) inhibitors, are cardioprotective, whereas others, such as insulin, have deleterious effects on the cardiovascular system. This narrative review assessed the impact of antidiabetic drugs on cardiovascular health in the management of diabetes mellitus. It critically examines various classes of these medications, including conventional options such as metformin and newer agents such as incretin-based therapies and SGLT-2.

Preference for Type 2 Diabetes Therapies in the United States: A Discrete Choice Experiment

Introduction

Type 2 diabetes mellitus (T2DM) is a chronic condition associated with substantial clinical and economic burden. As multiple therapeutic options are available, patient preferences on treatment characteristics are key in T2DM therapeutic decision-making. This study aimed to determine the preferences of US patients with T2DM for therapies recommended for first pharmacologic intensification after metformin.

Methods

As part of a discrete choice experiment, an online survey was designed using literature review and qualitative interview findings. Eligibility was met by US patients with T2DM who were aged 18 years or older with an HbA_1c ≥ 6.5%. Anonymized therapy profiles were created from six antidiabetic therapies including oral and injectable semaglutide, dulaglutide, empagliflozin, sitagliptin, and thiazolidinediones.

Results

Eligible patients (n = 500) had a mean HbA_1c of 7.4%, and a mean BMI of 32.0 kg/m², the majority of which (72.2%) were injectable-naïve. The treatment characteristic with greatest importance was mode and frequency of administration (35.5%), followed by body weight change (29.2%), cardiovascular event risk (19.1%), hypoglycemic event risk (9.9%), and HbA_1c change (6.5%). An oral semaglutide-like profile was preferred by 91.9–70.1% of respondents depending on the comparator agent, and preference was significant in each comparison (p < 0.05); an injectable semaglutide-like profile was preferred by 89.3–55.7% of respondents in each comparison depending on the comparator agent.

Conclusion

Patients with T2DM in the USA are significantly more likely to prefer oral or injectable semaglutide-like profiles over those of key comparators from the glucagon-like peptide 1 receptor agonist, sodium-glucose cotransporter 2 inhibitor, dipeptidyl peptidase 4 inhibitor, and thiazolidinedione classes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-022-02181-7.

Molecular toxicological alterations in the mouse hearts induced by sub-chronic thiazolidinedione drugs administration

Thiazolidinediones are well-known anti-diabetic drugs. However, they are not widely used due to their cardiotoxic effects. Therefore, in this study, we aimed to determine the molecular toxicological alterations induced in the mouse hearts after thiazolidinedione administration. Balb/c mice received doses clinically equivalent to those given to humans of the most commonly used thiazolidinediones, pioglitazone, and rosiglitazone for 30 days. After that, RNA samples were isolated from the hearts. The mRNA expression of cytochrome (cyp) p450 genes that synthesize the cardiotoxic 20-hydroxyeicosatetraenoic acid (20-HETE) in addition to 92 cardiotoxicity biomarker genes were analyzed using quantitative polymerase chain reaction array technique. The analysis demonstrated that thiazolidinediones caused a significant upregulation (p < 0.5) of the mRNA expression of cyp1a1, cyp4a12, itpr1, ccl7, ccr1, and b2 m genes. In addition, thiazolidinediones caused a significant (p < 0.05) downregulation of the mRNA expression of adra2a, bsn, col15a1, fosl1, Il6, bpifa1, plau, and reg3b genes. The most affected gene was itpr1 gene, which was upregulated by pioglitazone and rosiglitazone by sevenfold and 3.5-fold, respectively. In addition, pioglitazone caused significant upregulation of (p < 0.05) hamp, ppbp, psma2, sik1, timp1, and ucp1 genes, which were not affected significantly (p > 0.05) by rosiglitazone administration. In conclusion, this study showed that thiazolidinediones induce toxicological molecular alterations in the mouse hearts, such as the induction of cyp450s that synthesize 20-HETE, chemokine activation, inflammatory responses, blood clotting, and oxidative stress. These findings may help us understand the mechanism of cardiotoxicity involved in thiazolidinedione administration.

No Relevant Pharmacokinetic Drug-Drug Interaction Between the Sodium-Glucose Co-Transporter-2 Inhibitor Empagliflozin and Lobeglitazone, a Peroxisome Proliferator-Activated Receptor-γ Agonist, in Healthy Subjects

Purpose

Combination therapy with insulin-independent sodium-glucose cotransporter 2 inhibitors and thiazolidinedione drugs, such as lobeglitazone, has been reported to elicit potential additive efficacy in glycemic control in type 2 diabetes mellitus. This study was conducted to evaluate the pharmacokinetic (PK) drug–drug interactions between empagliflozin and lobeglitazone in healthy subjects.

Subjects and Methods

A randomized, open-label, multiple-dose study was conducted in 30 healthy subjects using a three-treatment, six-sequence, three-way crossover design. Subjects received one of the following treatments once daily for 5 days in each period: 25 mg empagliflozin, 0.5 mg lobeglitazone sulfate, or a combination. Serial blood sampling before every dose and up to 24 h after the last dose was performed during each treatment period. The PK parameters were estimated using noncompartmental methods with the plasma empagliflozin and lobeglitazone concentrations. The absence of a PK interaction was construed as the 90% confidence interval (90% CI) of maximum concentration at steady state (C_max,ss) and area under the concentration-time curve over the dosing interval (AUC_tau) for combination therapy-to-monotherapy ratios within the limits of 0.80–1.25.

Results

The steady-state plasma empagliflozin and lobeglitazone concentration-time profiles of combination therapy and monotherapy were comparable in the 25 subjects who completed the study. Coadministration of empagliflozin with lobeglitazone did not affect empagliflozin PK (with 90% CIs of 0.956–1.150 and 0.945–1.133 for C_max,ss and AUC_tau, respectively). Likewise, empagliflozin did not affect lobeglitazone C_max,ss or AUC_tau (with 90% CIs of 0.869–0.995 and 0.851–1.018, respectively). All treatment groups tolerated mild adverse events well.

Conclusion

The lack of PK interactions between lobeglitazone and empagliflozin in combination therapy, along with their good tolerability, indicates that the two drugs can be coadministered without dose adjustment.

Trial Registration Number

NCT02854748, Registered on August 7, 2016.

Cellular and molecular mechanisms in fibrosis

The activation of fibroblasts is required for physiological tissue remodelling such as wound healing. However, when the regulatory mechanisms are disrupted and fibroblasts remain persistently activated, the progressive deposition of extracellular matrix proteins leads to tissue fibrosis, which results in dysfunction or even loss of function of the affected organ. Although fibrosis has been recognized as a major cause of morbidity and mortality in modern societies, there are only few treatment options available that directly disrupt the release of extracellular matrix from fibroblasts. Intensive research in recent years, however, identified several pathways as core fibrotic mechanisms that are shared across different fibrotic diseases and organs. We discuss herein selection of those core pathways, especially downstream of the profibrotic TGF-β pathway, which are druggable and which may be transferable from bench to bedside.

The effect of adiponectin in the pathogenesis of non-alcoholic fatty liver disease (NAFLD) and the potential role of polyphenols in the modulation of adiponectin signaling

Non-alcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases worldwide, as it affects up to 30 % of adults in Western countries. Moreover, NAFLD is also considered an independent risk factor for cardiovascular diseases. Insulin resistance and inflammation have been identified as key factors in the pathophysiology of NAFLD. Although the mechanisms associated with the development of NAFLD remain to be fully elucidated, a complex interaction between adipokines and cytokines appear to play a crucial role in the development of this condition. Adiponectin is the most common adipokine known to be inversely linked with insulin resistance, lipid accumulation, inflammation and NAFLD. Consequently, the focus has been on the use of new therapies that may enhance hepatic expression of adiponectin downstream targets or increase the serum levels of adiponectin in the treatment NAFLD. While currently used therapies show limited efficacy in this aspect, accumulating evidence suggest that various dietary polyphenols may stimulate adiponectin levels, offering potential protection against the development of insulin resistance, inflammation and NAFLD as well as associated conditions of metabolic syndrome. As such, this review provides a better understanding of the role polyphenols play in modulating adiponectin signaling to protect against NAFLD. A brief discussion on the regulation of adiponectin during disease pathophysiology is also covered to underscore the potential protective effects of polyphenols against NAFLD. Some of the prominent polyphenols described in the manuscript include aspalathin, berberine, catechins, chlorogenic acid, curcumin, genistein, piperine, quercetin, and resveratrol.

Adipose Tissue Distribution, Inflammation and Its Metabolic Consequences, Including Diabetes and Cardiovascular Disease

Adipose tissue plays essential roles in maintaining lipid and glucose homeostasis. To date several types of adipose tissue have been identified, namely white, brown, and beige, that reside in various specific anatomical locations throughout the body. The cellular composition, secretome, and location of these adipose depots define their function in health and metabolic disease. In obesity, adipose tissue becomes dysfunctional, promoting a pro-inflammatory, hyperlipidemic and insulin resistant environment that contributes to type 2 diabetes mellitus (T2DM). Concurrently, similar features that result from adipose tissue dysfunction also promote cardiovascular disease (CVD) by mechanisms that can be augmented by T2DM. The mechanisms by which dysfunctional adipose tissue simultaneously promote T2DM and CVD, focusing on adipose tissue depot-specific adipokines, inflammatory profiles, and metabolism, will be the focus of this review. The impact that various T2DM and CVD treatment strategies have on adipose tissue function and body weight also will be discussed.

PPARγ inhibition regulates the cell cycle, proliferation and motility of bladder cancer cells

Peroxisome proliferator-activated receptor gamma (PPARγ) is a member of the nuclear receptor family of ligand-activated transcription factors and plays an important role in regulating cell proliferation, inflammation and lipid and glucose homeostasis. Our results revealed that PPARγ was up-regulated in human bladder cancer (BCa) tissues both at transcriptional and translational levels. Moreover, down-regulation of PPARγ mRNA or inhibition of PPARγ function (using GW9662, antagonist of PPARγ) could significantly suppress the proliferation of BCa cells. Furthermore, the cell cycle arrested in G0/G1 phase was also induced by the down-regulated PPARγ possibly through AKT-mediated up-regulation of p21/p27, whereas no significant transformation of apoptosis was observed. In addition, knockdown or inhibition of PPARγ might reduce the invasion and migration of BCa cells by affecting epithelial-mesenchymal transition-related proteins through AKT/GSK3β signalling pathway. Additionally, in vivo studies showed that BCa cell proliferation was significantly suppressed by GW9662. In conclusion, our results indicated that PPARγ might be crucial for BCa tumorigenesis by interfering with the motility and viability of BCa cells.

Phellopterin isolated from Angelica dahurica reduces blood glucose level in diabetic mice

Insulin resistance is the critical condition for the development of metabolic syndromes including type II diabetes and heart disease. To investigate the active components of Angelica dahurica root which is known to increase insulin sensitivity, its methanol extract was subfractionated. The ethyl acetate (EtOAc) fraction of the Angelica dahurica root extract significantly promoted adipocyte differentiation in 3T3-L1 preadipocyte cells. Among the three compounds isolated from the EtOAc extract (bergapten (1), imperatorin (2) and phellopterin (3)), phellopterin (3) induced the highest adipocyte differentiation at 25 and 50 μg/mL. In addition, treatment with imperatorin (2) and phellopterin (3) increased the mRNA expression of peroxisome proliferator-activated receptors γ (PPARγ). In diabetic animal model induced by high-fat diets (HFD) and streptozotocin (STZ), administration of phellopterin ((3), 1 mg/kg and 2 mg/kg) significantly reduced the levels of blood glucose, triglycerides and total cholesterol. Taken together, these results indicate that phellopterin (3) enhances adipocytes differentiation in 3T3-L1 preadipocytes, phellopterin (3) significantly prevents HFD/STZ-induced type Ⅱ diabetes. The present study also provides phellopterin (3) may be a valuable therapeutic alternative for enhancing insulin sensitivity through promotion of adipocyte differentiation and by increasing mRNA expression levels of PPARγ, which is a major mediator of insulin sensitivity.

Synthetic and phytocompounds based dipeptidyl peptidase-IV (DPP-IV) inhibitors for therapeutics of diabetes

Currently antidiabetic therapeutic strategies are mainly based on synthetic hypoglycemic agent. Antidiabetic drugs are associated with significant adverse effects of hypoglycemia, dysfunction of insulin and weight gain. Nowadays, the novel Dipeptidyl peptidase-IV (DPP-IV) inhibitors unique approach for the management of diabetes has been considered to be safe, as DPP-IV inhibitors reduce blood glucose level by monitoring hyperglycemia including positive effects on body weight as it remains neutral, improves glycated hemoglobin levels and do not induce hypoglycemia. Inhibitors help to protect degradation of Glucagon-like peptide-1 (GLP-1) and gastric inhibitory peptide (GIP), gut hormones which helps to suppresses postprandial glucagon release, delay gastric emptying and regulate satiety. Therefore, the innovation of DPP-IV inhibitor based drugs regulates activity of incretin hormones such as GLP-1 and GIP. Commercially available DPP-IV inhibitors are chemically synthesized with good therapeutic value. However, the durability and long-term safety of DPP-IV inhibitors remains to be established. On the other hand, phytocompounds-based DPP-IV inhibitors are alternative and safe to use as compared to synthetic. Numerous novel antidiabetic compounds and group of compounds emerging in clinical development are through DPP-IV inhibition. This review summarized recent progress made on DPP-IV inhibitors from both synthetic as well as from natural sources.

[Clinical effectiveness of pioglitazone in the combination treatment of patients with asthma concurrent with coronary heart disease]

AIM

To investigate the clinical effectiveness of pioglitazone in the combination treatment of patients with asthma concurrent with coronary heart disease (CHD).

SUBJECTS AND METHODS

Fifty patients aged 40-75 years with asthma concurrent with CHD were examined. External respiratory function (ERF), electrocardiograms, blood pressure (BP), and anthropometric measurements were assessed in all the patients. Blood and urine laboratory values and high-sensitivity C-reactive protein (hs-CRP) concentrations were estimated; endothelial function was determined measuring endothelium-dependent and endothelium-independent vasodilation (EDVD and EIVD). The patients were randomized into a comparison group receiving only standard therapy and a study group taking pioglitazone as part of combination therapy for 3 months.

RESULTS

At the randomization stage prior to pioglitazone combination therapy, the patient groups did not statistically significantly differ in basic clinical and anamnestic data. Three-month standard therapy resulted in stabilization of ERF and endothelial function. During the treatment, there were increases in the frequency of asthma symptoms and the duration of angina attacks, however, there was a decline in hs-CRP levels (p<0.001). Incorporation of pioglitazone into the standard treatment regimen of patients with asthma concurrent with CHD improved clinical disease control, decreased the degree of bronchial obstruction and the frequency of angina pain and asthma attacks using nitroglycerin and salbutamol, lowered systolic and diastolic blood pressure, improved EDVD (increases in the maximum linear velocity of blood flow after a test for reactive hyperemia (RH), index of reactivity (IR), and A% brachial artery (BA) diameter) and EIVD (increases in IR and A% BA diameter), and reduced systemic inflammation from hs-CRP values (p<0.001) and hypercholesterolemia from total cholesterol levels (p<0.02).

CONCLUSION

The incorporation of pioglitazone in the combination therapy of patients with asthma concurrent with CHD improves the clinical course of the diseases and increases their control, reduces systemic inflammation, and improves endothelial functional activity.

Antidiabetic Effects of Simple Phenolic Acids: A Comprehensive Review

Diabetes mellitus (DM) has become a major public health threat across the globe. Current antidiabetic therapies are based on synthetic drugs that very often have side effects. It has been widely acknowledged that diet plays an important role in the management of diabetes. Phenolic acids are widely found in daily foods such as fruits, vegetables, cereals, legumes, and wine and they provide biological, medicinal, and health properties. Simple phenolic acids have been shown to increase glucose uptake and glycogen synthesis, improve glucose and lipid profiles of certain diseases (obesity, cardiovascular diseases, DM, and its complication). The current review is an attempt to list out the antidiabetic effects of simple phenolic acids from medicinal plants and botanical foods.

Chemopreventive drugs: Mechanisms via inhibition of cancer stem cells in colorectal cancer

Recent epidemiological studies, basic research and clinical trials on colorectal cancer (CRC) prevention have helped identify candidates for effective chemopreventive drugs. However, because of the conflicting results of clinical trials or side effects, the effective use of chemopreventive drugs has not been generalized, except for patients with a high-risk for developing hereditary CRC. Advances in genetic and molecular technologies have highlighted the greater complexity of carcinogenesis, especially the heterogeneity of tumors. We need to target cells and processes that are critical to carcinogenesis for chemoprevention and treatment of advanced cancer. Recent research has shown that intestinal stem cells may serve an important role in tumor initiation and formation of cancer stem cells. Moreover, studies have shown that the tumor microenvironment may play additional roles in dedifferentiation, to enable tumor cells to take on stem cell features and promote the formation of tumorigenic stem cells. Therefore, early tumorigenic changes of stem cells and signals for dedifferentiation may be good targets for chemoprevention. In this review, I focus on cancer stem cells in colorectal carcinogenesis and the effect of major chemopreventive drugs on stem cell-related pathways.

Options for combination therapy in type 2 diabetes: comparison of the ADA/EASD position statement and AACE/ACE algorithm

Treating patients with diabetes is one of the most challenging and important activities a physician (primary care physician or specialist) can undertake. A key to successful therapy for type 2 diabetes is the insight that this condition is progressive and that the need for additional agents over time is normative. The ability to individualize therapy by patient and medication characteristics comes from experience and knowledge of pertinent clinical studies. However, guidelines from expert bodies such as the American Diabetes Association/European Association for the Study of Diabetes and American Association of Clinical Endocrinologists/American College of Endocrinology can help clinicians of all levels of expertise to approach therapy choices more rationally. There is unity across these guidelines about the role and benefits of metformin as first-line pharmacological treatment, probability of good efficacy, low risk of hypoglycemia, modest weight loss, and overall long-term data. Unfortunately, this unity does not extend to recommendations for subsequent pharmacological agents and their use in combination to intensify treatment when insulin is not (yet) appropriate. Across both statements, some drug classes seem more prominent, and looking at their benefit-risk profile, it is clear why this is the case. The most profound recent change in diabetes therapy has been the introduction of incretin therapies. Incretin therapies minimize 2 important adverse effects seen with many other therapies: hypoglycemia and weight gain. These agents have increased the range of options available for early intensification of treatment of type 2 diabetes. In combination with more established therapies, there are more opportunities than ever to accommodate patient preferences while improving glycemic control and harnessing extraglycemic benefits of a second (or third) agent.

[Type 2 diabetes mellitus: new treatments]

The benefits and problems associated with traditional hypoglycemic drugs, such as failure of beta cells, hypoglycemia and weight gain, that lead to a worsening of diabetes, are reviewed. New hypoglycemic drugs with incretin effect (glucagon-like peptide-1 agonists and dipeptidyl peptidase 4 inhibitors), achieve, in a glucose dependent manner, an glycosylated hemoglobin reduction without hypoglycemia or increase in body weight. Recently, another group of oral hypoglycemic drugs, sodium-glucose cotransporter type 2 inhibitors, have demonstrated efficacy in diabetes control by inhibiting renal glucose reabsorption. However, long-term effects and cardiovascular prevention remain to be demonstrated. We have more and better drugs nowadays. Hypoglycemic treatment should be customized (glycosylated hemoglobin levels, risk-benefit, risk of hypoglycemia, weight changes, cardiovascular risk), with a combination of drugs being necessary in most cases. However, we do not have yet an ideal hypoglycemic drug. Moreover we must remember that an early and intensive treatment of dyslipidemia and hypertension is essential for the prevention of cardiovascular disease in patients with type 2 diabetes.

Outcomes and lessons from the PROactive study

Beyond improvement of glucose control, thiazolidinediones exert pleiotropic effects, which may contribute to some cardiovascular protection. PROactive ("PROspective pioglitAzone Clinical Trial In macroVascular Events") has provided valuable, although controversial, information on the impact of pioglitazone on cardiovascular outcomes in a high-risk population of patients with type 2 diabetes and established macrovascular disease. Since 2005, there has been much debate on the relative value of the statistically non-significant 10% reduction in the quite challenging primary composite endpoint (combining cardiovascular disease-driven and procedural events in all vascular beds) versus the statistically significant 16% decrease in the more robust and conventional main secondary endpoint (all-cause mortality, myocardial infarction, and stroke) observed with pioglitazone. Revisiting PROactive deserves much interest following the report of inconclusive results on cardiovascular efficacy and safety of rosiglitazone in RECORD, the withdrawal (limitation) of rosiglitazone because of cardiovascular safety concern, the recent publication of a statement positioning pioglitazone in type 2 diabetes and the near availability of cheaper generics of pioglitazone. Although subanalyses may have more limited value from a statistical viewpoint, they nonetheless can provide valuable information on the drug efficacy/safety profile and clinical insights into which patients might benefit most (in terms of cardiovascular outcomes) from pioglitazone therapy.

Diabetic cardiomyopathy: bench to bedside

The study of diabetic cardiomyopathy is an area of significant interest given the strong association between diabetes and the risk of heart failure. Many unanswered questions remain regarding the clinical definition and pathogenesis of this metabolic cardiomyopathy. This article reviews the current understanding of diabetic cardiomyopathy with a particular emphasis on the unresolved issues that have limited translation of scientific discovery to patient bedside.

The role of peroxisome proliferator-activated receptors in carcinogenesis and chemoprevention

Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that are involved in regulating glucose and lipid homeostasis, inflammation, proliferation and differentiation. Although all of these functions might contribute to the influence of PPARs in carcinogenesis, there is a distinct need for a review of the literature and additional experimentation to determine the potential for targeting PPARs for cancer therapy and cancer chemoprevention. As PPAR agonists include drugs that are used for the treatment of metabolic diseases, a more complete understanding of the roles of PPARs in cancer will aid in determining any increased cancer risk for patients undergoing therapy with PPAR agonists.

Pharmacological modulation of cell death in atherosclerosis: a promising approach towards plaque stabilization?

Despite tremendous advances over the last 15 years in identifying vulnerable atherosclerotic plaques, the incidence of death and disability caused by such lesions still remains the number one health threat in developed countries. Therefore, new systemic or focal therapies aimed at decreasing the overall burden of disease, and a change to a more benign phenotype, are needed. Because cell death is a prominent feature of advanced atherosclerotic plaques with a major impact on plaque destabilization, an increasing number of compounds targeting the apoptotic or autophagic machinery in atherosclerosis are being explored, predominantly at the preclinical level. This review will provide an overview of these compounds, with a focus on both inhibition and stimulation of cell death, to prevent acute coronary syndromes and sudden cardiac death.

Can the electrophysiological action of rosiglitazone explain its cardiac side effects?

Recent large clinical trials found an association between the antidiabetic drug rosiglitazone therapy and increased risk of cardiovascular adverse events. The aim of this report is to elucidate the cardiac electrophysiological properties of rosiglitazone (R) on isolated rat and murine ventricular papillary muscle cells and canine ventricular myocytes using conventional microelectrode, whole cell voltage clamp, and action potential (AP) voltage clamp techniques. In histidine-decarboxylase knockout mice as well as in their wild types R (1-30 µM) shortened AP duration at 90% level of repolarization (APD(90)) and increased the AP amplitude (APA) in a concentration-dependent manner. In rat ventricular papillary muscle cells R (1-30 µM) caused a significant reduction of APA and maximum velocity of depolarization (V(max)) which was accompanied by lengthening of APD(90). In single canine ventricular myocytes at concentrations ≥10 µM R decreased the amplitude of phase-1 repolarization, the plateau potential and reduced V(max). R suppressed several ion currents in a concentration-dependent manner under voltage clamp conditions. The EC(50) value for this inhibition was 25.2±2.7 µM for the transient outward K(+ ) current (I(to)), 72.3±9.3 µM for the rapid delayed rectifier K(+ ) current (I(Kr)), and 82.5±9.4 µM for the L-type Ca(2+ ) current (I(Ca)) with Hill coefficients close to unity. The inward rectifier K(+ ) current (I(K1)) was not affected by R up to concentrations of 100 µM. Suppression of I(to), I(Kr), and I(Ca) has been confirmed under action potential voltage clamp conditions as well. The observed alterations in the AP morphology and densities of ion currents may predict serious proarrhythmic risk in case of intoxication with R as a consequence of overdose or decreased elimination of the drug, particularly in patients having multiple cardiovascular risk factors, such as elderly diabetic patients.