Repaglinide : a pharmacoeconomic review of its use in type 2 diabetes mellitus

Pharmacological mechanisms of Taohe Chengqi decoction in diabetic cardiovascular complications: A systematic review, network pharmacology and molecular docking

Background

Diabetic cardiovascular complications are the leading cause of diabetes-related deaths. These complications place an enormous and growing burden on global health systems and economies. The objective of this study was to conduct a systematic review on the therapeutic mechanisms of Taohe Chengqi Decoction (THCQD) in the treatment of diabetic cardiovascular complications. To predict the potential mechanisms of action of THCQD on diabetic cardiovascular complications using network pharmacology, and to validate these predictions through molecular docking analysis.

Methods

To collect relevant animal experiments, we searched a total of 6 databases. Eligibility for the study was determined based on inclusion and exclusion criteria. Data extraction was then performed on the literature. Methodological quality of animal studies was assessed using SYRCLE criteria. Based on network pharmacology, intersecting genes for THCQD and diabetic cardiovascular complications were obtained using Venny, PPI analysis and topology analysis of intersecting genes were performed; GO and KEGG were used for enrichment analysis and prediction of new targets of action. Molecular docking techniques were employed to model the interactions between drug components and target genes, thereby validating the results of network pharmacology predictions.

Results

A total of 16 studies were finally identified that fit the direction of this review. Included 6 studies of the myocardium, 1 study of the aortic arch, 5 studies of the femoral artery, 4 studies of the thoracic aorta. THCQD exhibited anti-inflammatory, anti-fibrotic and anti-atherosclerotic effects on cardiovascular complications in diabetic rats. Network pharmacology results showed that C0363 (Resveratrol), C0041 (Emodin), and C1114 (Baicalein) were the key components in the treatment of diabetic cardiovascular complications by THCQD. PPI results showed that INS, AKT1, TNF, ALB, IL6, IL1B as the genes that interact with the top 6. KEGG enrichment analysis identified the AGE-RAGE signaling pathway in diabetic complications as the most prominent pathway enriched by THCQD for diabetic cardiovascular complications genes. The results of molecular docking showed that the key active components demonstrated favorable interactions with their corresponding target genes.

Conclusion

In conclusion, the results of both basic and web-based pharmacological studies support the beneficial effects of the natural herbal formulation THCQD on diabetic cardiovascular complications. This decoction has anti-inflammatory and antifibrotic properties and is effective in ameliorating diabetic cardiovascular disease. The network pharmacology results further support these ideas and identify the AGE-RAGE signaling pathway in diabetic complications as possibly the most relevant pathway for THCQD in the treatment of diabetic cardiovascular complications. The extent of the therapeutic potential of all-natural herbal components in the treatment of diabetic cardiovascular disease merits further investigation.

Effectiveness of Duloxetine versus Other Therapeutic Modalities in Patients with Diabetic Neuropathic Pain: A Systematic Review and Meta-Analysis

Objectives: Diabetic peripheral neuropathy (DPN) is a chronic complication of diabetes mellitus (DM) with symptoms like intense pain and impaired quality of life. This condition has no treatment; instead, the pain is managed with various antidepressants, including duloxetine. The aim of this study is to analyze the evidence on the efficacy of duloxetine in the management of DPN. Methods: A systematic search in different databases was conducted using the keywords "diabetic neuropathy", "duloxetine therapy", "neuropathic pain", and "Diabetes Mellitus". Finally, eight studies were included in this meta-analysis. Results: All articles comparing duloxetine at different doses vs. a placebo reported significant differences in favor of duloxetine on pain scales like 24 h Average Pain Severity (standardized mean difference [SMD] = -1.06, confidence interval [CI] = -1.09 to -1.03, and p < 0.00001) and BPI Severity (SMD = -0.70, CI = -0.72 to -0.68, and p < 0.00001), among others. A total of 75% of the meta-analyses of studies comparing duloxetine at different doses showed a tendency in favor of the 120 mg/d dose. There were significant differences in favor of duloxetine when compared to routine care on the Euro Quality of Life (SMD = -0.04, CI = -0.04 to -0.03, and p < 0.00001) and SF-36 Survey (SMD = -5.86, CI = -6.28 to -5.44, and p < 0.00001) scales. There were no significant differences on the visual analog scale (VAS) when comparing duloxetine and gabapentin. Conclusions: Duloxetine appears to be effective in the management of DPN in different pain, symptom improvement, and quality of life scales.

Associated adverse health outcomes of polypharmacy and potentially inappropriate medications in community-dwelling older adults with diabetes

Aim: This study aimed to identify the association of chronic polypharmacy and potentially inappropriate medications (PIMs) with adverse health outcomes (AHOs) in community-dwelling older adults with diabetes in China. Methods: A 2-year retrospective cohort study was conducted using 11,829 community-followed older adults with diabetes and medical records from 83 hospitals and 702 primary care centers in Shenzhen, China. Chronic polypharmacy and PIMs were identified from prescription records using Beers' criteria, and their associated AHO was analyzed using multivariable logistic regression analysis. Results: The prevalence of chronic polypharmacy and at least one PIM exposure was 46.37% and 55.09%, respectively. The top five PIMs were diuretics, benzodiazepines, first-generation antihistamines, sulfonylureas, and insulin (sliding scale). Chronic polypharmacy was positively associated with all-cause hospital admission, admission for coronary heart disease, admission for stroke, admission for dementia, and emergency department visits. Exposure to PIMs was positively associated with all-cause hospital admission, admission for heart failure (PIMs ≥2), admission for stroke (PIMs ≥3), emergency department visits, bone fracture, constipation, and diarrhea. Conclusion: Chronic polypharmacy and PIMs were prevalent in older adults with diabetes in Chinese communities. Iatrogenic exposure to chronic polypharmacy and PIMs is associated with a higher incidence of different AHOs. This observational evidence highlights the necessity of patient-centered medication reviews for chronic polypharmacy and PIMs use in older patients with diabetes in primary care facilities in China and draws attention to the caution of polypharmacy, especially PIM use in older adults with diabetes in clinical practice.

Application of Nanoparticles: Diagnosis, Therapeutics, and Delivery of Insulin/Anti-Diabetic Drugs to Enhance the Therapeutic Efficacy of Diabetes Mellitus

Diabetes mellitus (DM) is a chronic metabolic disorder of carbohydrates, lipids, and proteins due to a deficiency of insulin secretion or failure to respond to insulin secreted from pancreatic cells, which leads to high blood glucose levels. DM is one of the top four noncommunicable diseases and causes of death worldwide. Even though great achievements were made in the management and treatment of DM, there are still certain limitations, mainly related to the early diagnosis, and lack of appropriate delivery of insulin and other anti-diabetic agents. Nanotechnology is an emerging field in the area of nanomedicine and NP based anti-diabetic agent delivery is reported to enhance efficacy by increasing bioavailability and target site accumulation. Moreover, theranostic NPs can be used as diagnostic tools for the early detection and prevention of diseases owing to their unique biological, physiochemical, and magnetic properties. NPs have been synthesized from a variety of organic and inorganic materials including polysaccharides, dendrimers, proteins, lipids, DNA, carbon nanotubes, quantum dots, and mesoporous materials within the nanoscale size. This review focuses on the role of NPs, derived from organic and inorganic materials, in the diagnosis and treatment of DM.

Drug interactions of meglitinide antidiabetics involving CYP enzymes and OATP1B1 transporter

Meglitinides such as repaglinide and nateglinide are useful to treat type 2 diabetes patients who follow a flexible lifestyle. They are short-acting insulin secretagogues and are associated with less risk of hypoglycemia, weight gain and chronic hyperinsulinemia compared with sulfonylureas. Meglitinides are the substrates of cytochrome P450 (CYP) enzymes and organic anion transporting polypeptide 1B1 (OATP1B1 transporter) and the coadministration of the drugs affecting them will result in pharmacokinetic drug interactions. This article focuses on the drug interactions of meglitinides involving CYP enzymes and OATP1B1 transporter. To prevent the risk of hypoglycemic episodes, prescribers and pharmacists must be aware of the adverse drug interactions of meglitinides.

Therapeutic molecules against type 2 diabetes: What we have and what are we expecting?

World Health Organization (WHO) has identified diabetes as one of the fastest growing non-communicable diseases with 422 million patients around the world in 2014. Diabetes, a metabolic disease, is characterized primarily by hyperglycemia which results in various macrovascular and microvascular complications like cardiovascular disease and neuropathies which can significantly deteriorate the quality of life. The body either does not manufactures enough insulin (type 1 diabetes or T1DM) or becomes insensitive to physiologically secreted insulin or both (type 2 diabetes or T2DM). The majority of the diabetic population is affected by type 2 diabetes. Currently, hyperglycemia is treated by a broad range of molecules such as biguanides, sulfonylurea, insulin, thiazolidinediones, incretin mimetics, and DPP-4 inhibitors exerting different mechanisms. However, new drug classes have indeed come in the market such as SGLT-2 inhibitors and other are in the experimental stages such as GPR 40 agonists, GSK-3 inhibitors, GK activators and GPR21 inhibitors which definitely could be anticipated as safe and effective for diabetes therapy. This article reviews the general approach to currently approved therapies for type 2 diabetes and focusing on novel approaches that could be a panacea and might be useful in the future for diabetes patients.

Exercise-induced ischemic preconditioning and the potential application to cardiac rehabilitation: a systematic review

Exercise-induced ischemic preconditioning (IPC) can be assessed by the results of the second of sequential exercise tests. Exercise-induced IPC is quantified by using the time to 1-mm ST-segment depression, the rate-pressure product at 1-mm ST-segment depression, the maximal ST-segment depression, and the rate-pressure product at the peak of exercise. Few studies reported whether exercise-induced IPC could be used in cardiovascular rehabilitation. A systematic review of the literature limited to human studies was performed using electronic databases, and the main key words were ischemic preconditioning, warm-up phenomenon, and exercise. After careful review, 38 articles were included in the systematic review. This review summarizes the molecular pathways of IPC and describes the first window of protection induced by sequential exercise tests, as well as the effect of medication on exercise-induced IPC. A section on the exercise protocol, mode of exercise, and intensity provides understanding as to what is needed for clinicians to induce IPC with sequential stress tests. The final section of the review is a discussion of the potential use of exercise-induced IPC in a cardiovascular rehabilitation setting. Even if exercise-induced IPC is a well-documented phenomenon, additional studies are needed in order to more fully understand its use in rehabilitation.

Impact of glucose-lowering drugs on cardiovascular disease in type 2 diabetes

Type 2 diabetes mellitus (T2DM) is characterized by multiple pathophysiologic abnormalities. With time, multiple glucose-lowering medications are commonly required to reduce and maintain plasma glucose concentrations within the normal range. Type 2 diabetes mellitus individuals also are at a very high risk for microvascular complications and the incidence of heart attack and stroke is increased two- to three-fold compared with non-diabetic individuals. Therefore, when selecting medications to normalize glucose levels in T2DM patients, it is important that the agent not aggravate, and ideally even improve, cardiovascular risk factors (CVRFs) and reduce cardiovascular morbidity and mortality. In this review, we examine the effect of oral (metformin, sulfonylureas, meglitinides, thiazolidinediones, DPP4 inhibitors, SGLT2 inhibitors, and α-glucosidase inhibitors) and injectable (glucagon-like peptide-1 receptor agonists and insulin) glucose-lowering drugs on established CVRFs and long-term studies of cardiovascular outcomes. Firm evidence that in T2DM cardiovascular disease can be reversed or prevented by improving glycaemic control is still incomplete and must await large, long-term clinical trials in patients at low risk using modern treatment strategies, i.e., drug combinations designed to maximize HbA1c reduction while minimizing hypoglycaemia and excessive weight gain.

Management of diabetes in the elderly

Management of diabetes in the elderly necessitates careful consideration of concomitant geriatric syndromes and comorbid conditions that increase the risk of complications, including severe hypoglycemia. Whereas healthy older adults can use therapeutic approaches recommended for their younger counterparts, treatment plans for frail elderly patients need to be simplified and A1c and blood pressure goals relaxed with the development of impairments in function, cognition, vision, and dexterity. The goals of diabetes management in the elderly should be to maintain quality of life and minimize symptomatic hyperglycemia and drug side effects, including hypoglycemia.

Structural studies of Pseudomonas and Chromobacterium ω-aminotransferases provide insights into their differing substrate specificity

The crystal structures and inhibitor complexes of two industrially important ω-aminotransferase enzymes from Pseudomonas aeruginosa and Chromobacterium violaceum have been determined in order to understand the differences in their substrate specificity. The two enzymes share 30% sequence identity and use the same amino acceptor, pyruvate; however, the Pseudomonas enzyme shows activity towards the amino donor β-alanine, whilst the Chromobacterium enzyme does not. Both enzymes show activity towards S-α-methylbenzylamine (MBA), with the Chromobacterium enzyme having a broader substrate range. The crystal structure of the P. aeruginosa enzyme has been solved in the holo form and with the inhibitor gabaculine bound. The C. violaceum enzyme has been solved in the apo and holo forms and with gabaculine bound. The structures of the holo forms of both enzymes are quite similar. There is little conformational difference observed between the inhibitor complex and the holoenzyme for the P. aeruginosa aminotransferase. In comparison, the crystal structure of the C. violaceum gabaculine complex shows significant structural rearrangements from the structures of both the apo and holo forms of the enzyme. It appears that the different rigidity of the protein scaffold contributes to the substrate specificity observed for the two ω-aminotransferases.

Effect of diabetes mellitus on pharmacokinetic and pharmacodynamic properties of drugs

The effects of diabetes mellitus on the pharmacokinetics and pharmacodynamics of drugs have been well described in experimental animal models; however, only minimal data exist for humans and the current knowledge regarding the effects of diabetes on these properties remains unclear. Nevertheless, it has been observed that the pharmacokinetics and pharmacodynamics of drugs are changed in subjects with diabetes. It has been reported that diabetes may affect the pharmacokinetics of various drugs by affecting (i) absorption, due to changes in subcutaneous adipose blood flow, muscle blood flow and gastric emptying; (ii) distribution, due to non-enzymatic glycation of albumin; (iii) biotransformation, due to regulation of enzymes/transporters involved in drug biotransformation; and (iv) excretion, due to nephropathy. Previously published data also suggest that diabetes-mediated changes in the pharmacokinetics of a particular drug cannot be translated to others. Although clinical studies exploring the effect of diabetes on pharmacodynamics are still very limited, there is evidence that disease-mediated effects are not limited only to pharmacokinetics but also alter pharmacodynamics. However, for many drugs it remains unclear whether these influences reflect diabetes-mediated changes in pharmacokinetics rather than pharmacodynamics. In addition, even though diabetes-mediated pharmacokinetics and pharmacodynamics might be anticipated, it is important to study the effect on each drug and not generalize from observed data. The available data indicate that there is a significant variability in drug response in diabetic subjects. The discrepancies between individual clinical studies as well as between ex vivo and clinical studies are probably due to (i) the restricted and focused population of subjects in clinical studies; (ii) failure to consider type, severity and duration of the disease; (iii) histopathological characteristics generally being missing; and (iv) other factors such as varying medication use, dietary protein intake, age, sex and obesity. The obesity epidemic in the developed world has also inadvertently influenced the directions of pharmacological research. This review attempts to map new information gained since Gwilt published his paper in Clinical Pharmacokinetics in 1991. Although a large body of research has been conducted and significant progress has been made, we still have to conclude that the available information regarding the effect of diabetes on pharmacokinetics and pharmacodynamics remains unclear and further clinical studies are required before we can understand the clinical significance of the effect. An understanding of diabetes-mediated changes as well as of the source of the variability should lead to the improvement of the medical management and clinical outcomes in patients with this widespread disease.

Investigation of the mechanism(s) involved in decreasing increased fibrinogen activity in hyperglycemic conditions using L-lysine supplementation

INTRODUCTION

Fibrinogen is a plasma glycoprotein that participates in the hemostasis system. Its malfunction has been reported as a consequence of diabetic complications. In this study, the inhibitory effect of L-Lysine (Lys) on the nonenzymatic glycation of fibrinogen was investigated in both in vitro and in vivo conditions.

MATERIALS AND METHODS

Fibrinogen was incubated with glucose in the presence or absence of Lys. Then, its structure was studied by fluorescence spectroscopy, circular dichroism, and electrophoresis. The Clauss method was used to determine fibrinogen activity. In addition, one of the two groups of type 2 diabetic patients receiving ordinary treatment was additionally treated with Lys for 3 months. Fibrinogen activity and some other parameters were evaluated in their plasma.

RESULTS

The results indicated increases in the activity of glycated fibrinogen in both of the in vivo and in vitro experiments. Advanced glycation end products were increased by time, as shown using fluorometry in both the plasma of the diabetic patients and the incubation medium of protein with glucose. The circular dichroism spectra showed some changes in the fibrinogen secondary and tertiary structures after glycation. The electrophoretic mobility of the glycated fibrinogen changed and the cross-link formation between the fibrinogen subunits due to glycation was observed. Lys inhibited all of the mentioned fibrinogen changes both in the in vitro experiments and after its administration to the diabetic patients.

CONCLUSION

Lys, as an inhibitor of protein glycation, improved fibrinogen's structure and function, both in vitro and in vivo.

Influence of atorvastatin on the pharmacodynamic and pharmacokinetic activity of repaglinide in rats and rabbits

Dyslipidemia is common in patients with type 2 diabetes. Statins are used as the first choice in treatment of diabetic dyslipidemia. Atorvastatin represents a first-line treatment option, alongside other hydroxyl methylglutaryl coenzyme A reductase inhibitors. Repaglinide is a short-acting, oral, insulin secretagogue that is used in the treatment of type 2 diabetes mellitus. Both the category of drugs undergo extensive metabolism with cytochrome enzyme system. This may lead to drug-drug interaction problems with altered repaglinide activity which is cautious. Repaglinide/atorvastatin/atorvastatin + repaglinide were administered orally to normal, diabetic rats, and to normal rabbits. Blood samples were collected at different time intervals and were analyzed for blood glucose by GOD-POD method using commercial glucose kits and repaglinide estimation in plasma by HPLC method. Diabetes was induced by alloxan 100 mg/kg body weight administered by I.P route. In the presence of atorvastatin, repaglinide activity was increased and maintained for longer period in diabetic rats compared with repaglinide matching control. The present study concludes co-administration of atorvastatin was found to improve repaglinide responses significantly in diabetic rats and improved glucose metabolism of atorvastatin played an important role and increased repaglinide levels by competitive CYP 3A4 enzyme inhibition by atorvastatin could be added advantage for anti hyperglycemic activity.

Pharmacoeconomics and aging

The aging of the general population in industrialized countries has brought to public attention the increasing incidence of age-related clinical conditions, because the long-term impact of diseases on functional status and on costs are greater in older people than in any other age group. With the aging of the population, it is becoming increasingly important to quantify the burden of illness in the elderly; this will be vital not only in planning for the necessary health services that will be required in coming years, but also in order to measure the benefit to be expected from interventions to prevent disability in older people. The management of multiple and chronic disorders has become a more important issue for healthcare authorities because of increasing requests for medical assistance and healthcare interventions. Among these, pharmacological treatments and drug utilization in older people are pressing issues for healthcare managers and politicians; indeed, a relatively small proportion of the population accounts for a substantial part of public drug costs. Two key sources of pressure are well known: the growing number of elderly persons, who are the highest per-capita users of medicines, and the introduction of new, often more expensive, medicines. On the other hand, the development of strategies for controlling costs, while providing the elderly with equitable access to needed pharmaceuticals, should be based on an evaluation of the economic impact of pharmacological care in older people, taking into account the burden of illness, drug utilization data, drug technology assessment evidence and results. Furthermore, there are major factors affecting pharmacological care in older people: for example inappropriate prescribing, lack of adherence and compliance, and the burden of adverse drug events. The assessment of these factors should be considered a priority in pharmacoeconomic evaluations in the aging population, and the most relevant evidence will be reviewed in this paper with examples referring to particular settings or conditions and diseases, such as the presence of cardiovascular risk factors, diabetes and chronic pain.

The cumulative burden of oral corticosteroid side effects and the economic implications of steroid use

Oral corticosteroids (OCS) are a key part of therapy regimens for a diverse variety of conditions. Despite their efficacy, they are associated with a wide variety of adverse events. The purpose of this review was to identify the range of adverse events that have been reported to be related to oral corticosteroids, examine the factors that influence their incidence and estimate the economic burden caused by these adverse events. In 61 identified studies, 21 different categories of OCS related adverse events were reported with increased fracture risk being the category most frequently described. Most studies that examined factors linked to the incidence of OCS related adverse events found that dose, age, gender, duration of use, treatment history, smoking habits or cholesterol level were influential in determining risk. Additionally, a cumulative economic analysis of selected adverse events found the annual cost of treating these events in the UK to be at least 165 pounds per patient taking OCS. The clinical and economic burden of OCS related adverse events highlights the need for OCS sparing therapies to be developed.

Impact of therapeutic advances on hypoglycaemia in type 2 diabetes

Patients with type 2 diabetes experience hypoglycaemia less frequently than those with type 1 diabetes. Some protection against hypoglycaemia is afforded by the relatively intact glucose counter-regulatory pathways that characterize the pathophysiology of early type 2 diabetes. To some extent, this protection explains why hypoglycaemic episodes in intensively treated individuals with type 2 diabetes, when they occur, are rarely severe. As diabetes progresses and therapy intensifies to achieve recommended glycaemic goals, hypoglycaemia frequency and severity increase. Thus, when it comes to instituting intensive therapy, fear of hypoglycaemia may contribute to health-care providers' 'clinical inertia'. Because maintaining glycaemic control is so important to both public and individual health, many new therapies and technologies have been developed. This manuscript reviews and considers whether these advancements in therapy make glycaemic goals easier to achieve by minimizing hypoglycaemia. Putting the hypoglycaemia experienced by type 2 diabetes patients into appropriate clinical perspective, the impact of recent progress made in pharmacotherapy, drug delivery systems, and BG monitoring on hypoglycaemia incidence is largely positive. The extent to which this progress can effect improvement over traditional therapies will, however, depend upon patient (and provider) education, motivation and behaviour change.

Cost-effectiveness analysis of thiazolidinediones in uncontrolled type 2 diabetic patients receiving sulfonylureas and metformin in Thailand

OBJECTIVE

The national essential drug committee in Thailand suggested that only one of thiazolidinediones be included in hospital formulary but little was know about their cost-effectiveness values. This study aims to determine an incremental cost-effectiveness ratio of pioglitazone 45 mg compared with rosiglitazone 8 mg in uncontrolled type 2 diabetic patients receiving sulfonylureas and metformin in Thailand.

METHODS

A Markov diabetes model (Center for Outcome Research model) was used in this study. Baseline characteristics of patients were based on Thai diabetes registry project. Costs of diabetes were calculated mainly from Buddhachinaraj hospital. Nonspecific mortality rate and transition probabilities of death from renal replacement therapy were obtained from Thai sources. Clinical effectiveness of thiazolidinediones was retrieved from a meta-analysis. All analyses were based on the government hospital policymaker perspective. Both cost and outcomes were discounted with the rate of 3%. Base-case analyses were analyzed as incremental cost per quality-adjusted life year (QALY) gained. A series of sensitive analyses were performed.

RESULTS

In base-case analysis, the pioglitazone group had a better clinical outcomes and higher lifetime costs. The incremental cost per QALY gained was 186,246 baht (US$ 5389). The acceptability curves showed that the probability of pioglitazone being cost-effective was 29% at the willingness to pay of one time of Thai gross domestic product per capita (GDP per capita). The effect of pioglitazone on %HbA1c decrease was the most sensitive to the final outcomes.

CONCLUSIONS

Our findings showed that in type 2 diabetic patients who cannot control their blood glucose under the combination of sulfonylurea and metformin, the use of pioglitazone 45 mg fell in the cost-effective range recommended by World Health Organization (one to three times of GDP per capita) on average, compared to rosiglitazone 8 mg. Nevertheless, based on sensitivity analysis, its probability of being cost-effective was quite low. Hospital policymakers may consider our findings as part of information for the decision-making process.

Importance and challenges of studying marketed drugs: what is a phase IV study? Common clinical research designs, registries, and self-reporting systems

The new drug application database submitted to the US Food and Drug Administration for drug approval (phases I-III or phases 1-3) is limited both in scope and size. Although randomized controlled trials, the hallmark of phase III trials, are the gold standard for the drug-approval process, they invariably have a number of limitations, including relatively small sample sizes, selective populations, short follow-up, the use of intermediate (surrogate) endpoints (almost always), and limited generalizability. The challenges of monitoring drugs once approved are also numerous. After approval by the Food and Drug Administration, marketed drugs undergo continued scrutiny, and this scrutiny is increasing because of problems that have surfaced with some drugs after their approval. Postmarketing research includes a variety of study designs and the use of registries and self-reporting of drug side effects. Along with this has come great confusion about what postmarketing research is and what a phase IV study is. Among the important strengths of phase IV research are the exposure of a broader range of patients to the drug under study, resulting in more "real-world" information about the drug's safety and efficacy, and consideration of a broader range of clinical endpoints. As a result, phase IV, or postmarketing research, has become an integral part of the drug evaluation process for a wide range of agents. The authors discuss the different types of study designs that are common under the phase IV terminology and provide some examples. They also discuss the use of registries and self-reporting of adverse events using the MedWatch System.

Treating dyslipidaemia in the setting of diabetes mellitus and cardiovascular disease: a less commonly perceived therapeutic perspective in clinical practice

Diabetes mellitus and cardiovascular disease are being managed more belligerently in recent times, with multifactorial cardiovascular risk reduction being the focus of therapeutic interventions. We review some of the caveats to be exercised in the treatment of these patients that are pertinent to clinicians in daily clinical practice.

Repaglinide in the management of new-onset diabetes mellitus after renal transplantation

The purpose of this study was to investigate the use of the short-acting insulin secretion drug repaglinide in new-onset diabetes mellitus (NODM) after renal transplantation. Twenty-three Caucasian patients with NODM after renal transplantation were selected to receive repaglinide therapy and were followed for at least 6 months. A control group treated with rosiglitazone was chosen for comparison. Successful repaglinide treatment was defined as a significant improvement of blood glucose concentrations and HbA1c <7% in the absence of glucosuria and without the need for the addition of further anti-diabetic agents. After 6 months of treatment with repaglinide, 14 of the 23 patients were successfully treated. Mean HbA1c decreased from 7.6 +/- 0.6% to 5.8 +/- 0.6% in 14 patients treated successfully. In nine patients, hyperglycemia persisted, and they were switched to insulin treatment (HbA1c 8.5 +/- 2.9% at the beginning to 7.4 +/- 2.2%). Mean serum creatinine levels, cyclosporine A and tacrolimus blood levels did not change significantly following institution of repaglinide therapy. The rate of successful treatment and the degree of HbA1c decrease were similar compared to rosiglitazone-treated control patients. The data from our observational study indicate that repaglinide can be an effective treatment option in Caucasian patients with NODM after renal transplantation.

The Metabolic Syndrome: Recognition and Management

The National Cholesterol Education Program defines the metabolic syndrome as three or more of five abnormalities: waist circumference of >40 in (102 cm) for men or >35 in (88 cm) for women, triglyceride level of > or =150 mg/dL, high-density lipoprotein cholesterol of <40 mg/dL in men or <50 mg/dL in women, blood pressure of > or =130 or > or =85 mm Hg, and fasting glucose of > or =110 mg/dL. It is related to insulin resistance, but the two terms are not synonymous. Both are associated strongly with obesity. The metabolic syndrome is important as an indicator of increased risk of cardiovascular disease (CVD) in patients with and without clinical CVD. The CVD risk of the metabolic syndrome is greater than that conferred by any single CVD risk factor. Since risk factors tend to cluster, if one component of the metabolic syndrome is present, one should assess for other risk factors. The metabolic syndrome is also predictive of new-onset type 2 diabetes. Early diagnosis provides justification for measures that can improve components of the syndrome and reduce CVD risk. The management strategy for metabolic syndrome focuses on overall CVD risk rather than single risk factors; effective therapy includes priority for weight reduction and increased physical activity. Pharmacotherapy is typically needed for control of high blood pressure, hypercoagulability, and increased levels of blood glucose and triglycerides.

Inhibition of intestinal and renal Na+-glucose cotransporter by naringenin

Reduction in glucose uptake constitutes a possible means of controlling diabetic hyperglycemia. Using purified intestinal brush border membrane vesicles and everted intestinal sleeves, we have demonstrated that naringenin, a flavonoid present in citrus fruits and juices, significantly inhibited glucose uptake in the intestine. In addition, naringenin also elicited inhibitory actions towards glucose uptake in renal brush border membrane vesicles. Naringin, a glycoside of naringenin, was totally inactive in these aspects. Naringenin exhibited moderate inhibitory action on glucose uptake in rabbit intestinal brush border membrane vesicles, and showed strong inhibitory action in rat everted intestinal sleeves. The IC(50) values were 205.9 and 2.4 micromol/l, respectively. Lineweaver-Burk analysis demonstrated that naringenin inhibited glucose uptake in rat everted intestinal sleeves in a competitive manner with a K(i) value of 1.1 micromol/l. Glucose uptake activities in both the intestinal and renal brush border membrane vesicles of diabetic rats were significantly higher than in normal rats. Naringenin (500 microM) reduced glucose uptake by more than 60% in both the intestinal and renal brush border membrane vesicles of diabetic rats to a level similar to that of the normal rats. The IC(50) values of naringenin in the renal brush border membrane vesicles of normal and diabetic rats were 323.9 and 166.1 micromol/l, respectively. These results suggest that inhibition of intestinal glucose uptake and renal glucose reabsorption explains, in part at least, the in vivo antihyperglycemic action of naringenin and its derivatives. The possible application of these natural compounds in controlling hyperglycemia warrants further investigations.

Quinolizidine alkaloids isolated from Lupinus species enhance insulin secretion

We have analyzed the effect of quinolizidine alkaloids from Lupinus species upon insulin secretion. Isolated normal rat islets were incubated with 3.3, 8.3, and 16.7 mM glucose, in the presence or absence of different concentrations of lupanine (0.05, 0.5, and 1.0 mM), 13-alpha-OH lupanine, 17-oxo-lupanine, and 2-thionosparteine. Insulin release was measured by radioimmunoassay. While 2-thionosparteine enhanced insulin secretion at all glucose concentrations, lupanine did at 8.3 and 16.7 mM, and 13-alpha-OH lupanine or 17-oxo-lupanine only at 16.7 mM glucose. Diazoxide (0.1 mM) decreased the effect of all alkaloids, without suppressing it completely. Consequently, blockage of beta-cell K(ATP)-sensitive channels is at least one of the mechanisms involved in the enhancing secretagogue effects of quinolizidine alkaloids. The fact that 13-alpha-OH lupanine and 17-oxo-lupanine only exert their secretagogue effect at high glucose concentrations could be of additional value when considering their potential use in the treatment of type 2 diabetes.