Sulfonylureas and their use in clinical practice

A comprehensive review of the FDA-approved labels of diabetes drugs: Indications, safety, and emerging cardiovascular safety data

AIMS

FDA-approved drug labels are an important source of information for clinicians who prescribe medications for treatment of diabetes. We reviewed drug labels to (1) understand the landscape of classes of medications approved for type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM), (2) explore the indications and safety information and (3) examine their cardiovascular safety.

METHODS

We searched four public references and reviewed all FDA-approved labels for "indication and usage," "adverse effects," "warnings and precautions," and "cardiovascular outcomes" from October 1982 to July 2016. We also reviewed FDA drug-safety communications from January 2015 to May 2017.

RESULTS

The labels reveal 12 classes of medications approved for T2DM with only 2 classes approved for T1DM. There is emerging evidence about cardiovascular safety and risk reduction from diabetes medications which is now being incorporated in drug labels.

CONCLUSIONS

All currently available diabetes medications are approved for adults with T2DM with a remarkably limited number for adults with T1DM and children with T1DM or T2DM. The incorporation of emerging data on cardiovascular outcomes in FDA drug labels is expected to influence the way physicians treat patients with diabetes.

Estimating the effects of second-line therapy for type 2 diabetes mellitus: retrospective cohort study

OBJECTIVE

Metformin is the recommended initial drug treatment in type 2 diabetes mellitus, but there is no clearly preferred choice for an additional drug when indicated. We compare the counterfactual drug effectiveness in lowering glycated hemoglobin (HbA1c) levels and effect on body mass index (BMI) of four diabetes second-line drug classes using electronic health records.

STUDY DESIGN AND SETTING

Retrospective analysis of electronic health records of US-based patients in the Explorys database using causal inference methodology to adjust for patient censoring and confounders.

PARTICIPANTS AND EXPOSURES

Our cohort consisted of more than 40 000 patients with type 2 diabetes, prescribed metformin along with a drug out of four second-line drug classes-sulfonylureas, thiazolidinediones, dipeptidyl peptidase 4 (DPP-4) inhibitors and glucagon-like peptide-1 agonists-during the years 2000-2015. Roughly, 17 000 of these patients were followed for 12 months after being prescribed a second-line drug.

MAIN OUTCOME MEASURES

HbA1c and BMI of these patients after 6 and 12 months following treatment.

RESULTS

We demonstrate that all four drug classes reduce HbA1c levels, but the effect of sulfonylureas after 6 and 12 months of treatment is less pronounced compared with other classes. We also estimate that DPP-4 inhibitors decrease body weight significantly more than sulfonylureas and thiazolidinediones.

CONCLUSION

Our results are in line with current knowledge on second-line drug effectiveness and effect on BMI. They demonstrate that causal inference from electronic health records is an effective way for conducting multitreatment causal inference studies.

Weight effects of antidiabetic agents

Obesity and diabetes are on the rise, which remains a continuous health concern worldwide. It is important to consider weight effects of antidiabetic agents prior to initiation as different antidiabetic agents impact weight differently. Areas covered: New agents to treat diabetes, glucagon-like peptide-1 receptor agonists and sodium glucose cotransporter 2 inhibitors, have emerged over recent years that have been shown to result in weight reduction. Unfortunately, other antidiabetic medications used can cause weight gain such as with insulin, sulfonylureas, and thiazolidediones while some remain weight neutral (metformin and dipeptidyl peptidase-4 inhibitors). The weight effects of these antidiabetic medications described are from select relevant guidelines, clinical trials, reviews, and meta-analysis found through PubMed and Ovid databases up to July 2017. Expert commentary: This article summarizes the current evidence available on the weight effects of these agents in patients with diabetes. Evaluating potential risks, such as weight gain, with potential benefits, such as improvement in glycemic control, will help with designing optimal therapeutic diabetes regimens.

Regulation of Endogenous (Male) Rodent GLP-1 Secretion and Human Islet Insulin Secretion by Antagonism of Somatostatin Receptor 5

Incretin and insulin responses to nutrient loads are suppressed in persons with diabetes, resulting in decreased glycemic control. Agents including sulfonylureas and dipeptidyl peptidase-4 inhibitors (DPP4i) partially reverse these effects and provide therapeutic benefit; however, their modes of action limit efficacy. Because somatostatin (SST) has been shown to suppress insulin and glucagonlike peptide-1 (GLP-1) secretion through the Gi-coupled SST receptor 5 (SSTR5) isoform in vitro, antagonism of SSTR5 may improve glycemic control via intervention in both pathways. Here, we show that a potent and selective SSTR5 antagonist reverses the blunting effects of SST on insulin secretion from isolated human islets, and demonstrate that SSTR5 antagonism affords increased levels of systemic GLP-1 in vivo. Knocking out Sstr5 in mice provided a similar increase in systemic GLP-1 levels, which were not increased further by treatment with the antagonist. Treatment of mice with the SSTR5 antagonist in combination with a DPP4i resulted in increases in systemic GLP-1 levels that were more than additive and resulted in greater glycemic control compared with either agent alone. In isolated human islets, the SSTR5 antagonist completely reversed the inhibitory effect of exogenous SST-14 on insulin secretion. Taken together, these data suggest that SSTR5 antagonism should increase circulating GLP-1 levels and stimulate insulin secretion (directly and via GLP-1) in humans, improving glycemic control in patients with diabetes.

Effectiveness of sitagliptin compared to sulfonylureas for type 2 diabetes mellitus inadequately controlled on metformin: a systematic review and meta-analysis

OBJECTIVE

To assess the effectiveness of sitagliptin compared to sulfonylureas as add-on to metformin in adults with type 2 diabetes mellitus from both randomised controlled trials (RCTs) and 'real-world' non-randomised studies.

METHODS AND ANALYSES

We conducted a systematic review of EMBASE, MEDLINE, CENTRAL and grey literature for RCTs and non-randomised studies. We reported outcomes relating to change in HbA1c, fasting glucose, weight, blood pressure and lipids from baseline and need for treatment change. No study investigating macrovascular and microvascular diabetes complications was found. Meta-analysis was used where studies were sufficiently homogenous.

RESULTS

Seven RCTs and five non-randomised studies were eligible for inclusion from 1335 articles retrieved. Meta-analysis of three homogenous RCTs revealed a statistically significant decrease in weight with sitagliptin when compared to sulfonylureas (weighted mean difference (WMD) -2.05 kg; 95% CI -2.38 to -1.71); however, a similar change from baseline in HbA1c (WMD 0.05; 95% CI -0.03 to 0.12), fasting glucose (WMD 0.11; 95% CI -0.08 to -0.29), blood pressure, lipids and the proportion achieving HbA1c <7% by study end (OR 0.98; 95% CI 0.85 to 1.13) was observed.Non-randomised studies identified consisted of four prospective and one retrospective cohort study. Three of these five studies were of moderate/high quality, and results though less precise suggested similar real-world comparative glycaemic and weight effectiveness for both treatments. Data from two cohort studies suggested that treatment change (HR 0.65; 95% CI 0.57 to 0.73) and insulin initiation (HR 0.76; 95% CI 0.65 to 0.90) were less likely among those prescribed sitagliptin; however, inadequate reporting of HbA1c at time of treatment change made interpreting results challenging.

CONCLUSION

Sitagliptin users experienced modest weight loss compared to gain with sulfonylureas; however, this difference was around 2 kg, which may not be of major clinical significance for most individuals. Similar change was observed across most other effectiveness outcomes reported. Further studies are needed to address longer-term effectiveness outcomes for sitagliptin compared to sulfonylureas as add-on to metformin.

PROSPERO REGISTRATION NUMBER

CRD42016033983.

Anti-diabetic drug binding site in a mammalian KATP channel revealed by Cryo-EM

Sulfonylureas are anti-diabetic medications that act by inhibiting pancreatic K_ATP channels composed of SUR1 and Kir6.2. The mechanism by which these drugs interact with and inhibit the channel has been extensively investigated, yet it remains unclear where the drug binding pocket resides. Here, we present a cryo-EM structure of a hamster SUR1/rat Kir6.2 channel bound to a high-affinity sulfonylurea drug glibenclamide and ATP at 3.63 Å resolution, which reveals unprecedented details of the ATP and glibenclamide binding sites. Importantly, the structure shows for the first time that glibenclamide is lodged in the transmembrane bundle of the SUR1-ABC core connected to the first nucleotide binding domain near the inner leaflet of the lipid bilayer. Mutation of residues predicted to interact with glibenclamide in our model led to reduced sensitivity to glibenclamide. Our structure provides novel mechanistic insights of how sulfonylureas and ATP interact with the K_ATP channel complex to inhibit channel activity.

The Infamous, Famous Sulfonylureas and Cardiovascular Safety: Much Ado About Nothing?

PURPOSE OF REVIEW

Sulfonylureas (SUs) are one of the most commonly used glucose-lowering agents worldwide. While their efficacy is undisputed, their cardiovascular safety has been debated since the 1970's.

RECENT FINDINGS

With no dedicated cardiovascular studies to definitively answer this question, observational studies and meta-analyses abound and have reported divergent results, fueling the controversy. Studies that compared SUs to metformin or newer agents, like GLP-1 agonists and SGLT2 inhibitors, suggest a difference in cardiovascular events, yet this is likely the result of beneficial effects of the latter. Studies comparing SUs to other agents have been reassuring. SUs remain a common choice of treatment for patients with type 2 diabetes due to their exceptional value. They are effective at lowering glucose and thus contributing to the prevention of microvascular complications. Weight gain and hypoglycemia are their main side effects, although less severe when compared to insulin treatment. Their cardiovascular safety will remain a controversial topic due to lack of conclusive data, but there is no definitive evidence of harm with the second-generation agents.

Dual Therapy Appears Superior to Monotherapy for Low-Income Individuals With Newly Diagnosed Type 2 Diabetes

BACKGROUND

There are variable recommendations regarding initiating monotherapy or dual therapy in patients with newly diagnosed type 2 diabetes (T2D). Clear initial strategies are of particular importance in underserved settings where access to care and financial burdens are significant barriers.

OBJECTIVES

To provide descriptive data of metabolic outcomes to therapy regimens for low-income individuals with newly diagnosed T2D placed on oral hypoglycemic agents (OAs).

METHODS

We conducted a retrospective chart review of low-income individuals with newly diagnosed T2D initiated on OAs. We provided descriptive data and then evaluated the effects of OA regimens (ie, mono-, dual-, transition [from mono to dual or vice versa] therapy) on hemoglobin A1c (A1c) (baseline to 12 months).

RESULTS

A total of 309 patients were included in the study. At 12 months, the mean decrease in A1c for the entire sample was -2.36% (9.37% to 7.01%). Patients prescribed dual therapy had a greater change of A1c compared to those taking monotherapy with metformin (-1.11%, P < .01). Patients who transitioned therapies did not differ in change of A1c compared to monotherapy.

CONCLUSION

Initiation of dual therapy was superior to metformin monotherapy or transitioning therapies and may be preferred for low-income individuals with newly diagnosed T2D.

Loureirin B promotes insulin secretion through inhibition of KATP channel and influx of intracellular calcium

The development of new diabetes drugs continues to be explored. Loureirin B, a flavonoid, extracted from Dracaena cochinchinensis, has been confirmed to increase insulin secretion and decrease blood glucose levels. For searching the promotion of insulin secretion with the treatment of loureirin B, experiments were employed based on cell experiments and computational methods. First, promotion of insulin secretion was dependent on extracellular glucose concentration. At the genetic level, loureirin B enhanced the relative mRNA level of Pdx-1 and MafA. Meanwhile the intracellular level of ATP increased due to the continuous absorption of glucose. Further experiments showed that the currents of K_ATP channel on Ins-1 cells were inhibited and the voltage-dependent calcium channels were subsequently activated. The increase of Cx43 protein expression might mediate the Ca²⁺ to the intracellular. Through computational simulation, we hypothesized that loureirin B might interact with K_ATP channels to promote insulin secretion. In conclusion, it could be concluded that loureirin B promoted insulin secretion mainly through increasing mRNA level of Pdx-1, MafA, intracellular ATP level, inhibiting the K_ATP current, influx of Ca²⁺ to the intracellular.

Pro- and Antiarrhythmic Actions of Sulfonylureas: Mechanistic and Clinical Evidence

Sulfonylureas are the most commonly used second-line drug class for treating type 2 diabetes mellitus (T2DM). While the cardiovascular safety of sulfonylureas has been examined in several trials and nonrandomized studies, little is known of their specific effects on sudden cardiac arrest (SCA) and related serious arrhythmic outcomes. This knowledge gap is striking, because persons with DM are at increased risk of SCA. In this review, we explore the influence of sulfonylureas on the risk of serious arrhythmias, with specific foci on ischemic preconditioning, cardiac excitability, and serious hypoglycemia as putative mechanisms. Elucidating the relationship between individual sulfonylureas and serious arrhythmias is critical, especially as the diabetes epidemic intensifies and SCA incidence increases in persons with diabetes.

Antiplatelet and anticoagulant therapy in elderly people with type 2 diabetes mellitus in Poland (based on the PolSenior Study)

INTRODUCTION

Type 2 diabetes mellitus (T2DM) is an important and common cardiovascular risk factor. The purpose of the study was to evaluate the frequency of use of oral antiplatelet drugs (OAPs) and oral anticoagulant drugs (OACs) among the elderly with T2DM in Poland.

MATERIAL AND METHODS

The study was based on the data collected in the Polish national PolSenior study.

RESULTS

Among 4979 PolSenior participants aged 65 and over, 883 (17.8%) had previously diagnosed T2DM. Among them, 441 (49.9%) used at least one drug in pharmacological cardiovascular prevention, i.e. OAPs (mostly ASA) in 405 (45.9%) cases and OACs in 38 (4.3%). The use of these drugs significantly depended on the sex (p = 0.02) and personal income (p = 0.05). Age, place of residence and level of education did not affect the prevalence of pharmacological prevention. Previous stroke and myocardial infarction were mostly associated with OAPs, whereas a history of atrial fibrillation (AF) was related to OAC treatment. Among participants treated with OAPs, therapy was applied as secondary cardiovascular prevention in 211 (52.1%) subjects, and as primary prevention in 194 (47.9%) subjects. Among participants treated with OACs, 24 (64.9%) persons had a history of AF. Secondary cardiovascular pharmacological prevention should be considered in 45 untreated participants (12.5%), and primary cardiovascular pharmacological prevention (SCORE ≥ 10 and/or AF) in 154 participants (42.7%).

CONCLUSIONS

Cardiovascular pharmacological prevention in the elderly with T2DM in Poland seems to be unsatisfactory. Educational programmes concerning current recommendations for pharmacological cardiovascular prevention should be developed among general practitioners.

Glibenclamide pretreatment protects against chronic memory dysfunction and glial activation in rat cranial blast traumatic brain injury

Blast traumatic brain injury (bTBI) affects both military and civilian populations, and often results in chronic deficits in cognition and memory. Chronic glial activation after bTBI has been linked with cognitive decline. Pharmacological inhibition of sulfonylurea receptor 1 (SUR1) with glibenclamide was shown previously to reduce glial activation and improve cognition in contusive models of CNS trauma, but has not been examined in bTBI. We postulated that glibenclamide would reduce chronic glial activation and improve long-term memory function after bTBI. Using a rat direct cranial model of bTBI (dc-bTBI), we evaluated the efficacy of two glibenclamide treatment paradigms: glibenclamide prophylaxis (pre-treatment), and treatment with glibenclamide starting after dc-bTBI (post-treatment). Our results show that dc-bTBI caused hippocampal astrocyte and microglial/macrophage activation that was associated with hippocampal memory dysfunction (rapid place learning paradigm) at 28days, and that glibenclamide pre-treatment, but not post-treatment, effectively protected against glial activation and memory dysfunction. We also report that a brief transient time-window of blood-brain barrier (BBB) disruption occurs after dc-bTBI, and we speculate that glibenclamide, which is mostly protein bound and does not normally traverse the intact BBB, can undergo CNS delivery only during this brief transient opening of the BBB. Together, our findings indicate that prophylactic glibenclamide treatment may help to protect against chronic cognitive sequelae of bTBI in warfighters and other at-risk populations.

Sterile leukocyturia affects urine neutrophil gelatinase-associated lipocalin concentration in type 2 diabetic patients

INTRODUCTION

Increased urine neutrophil gelatinase-associated lipocalin (uNGAL) concentrations are associated with the early phase of kidney damage. Urine NGAL may increase due to production by neutrophils present in urine, particularly in patients with urinary tract infections. The aim of the study was to assess the relationship between sterile leukocyturia and uNGAL concentrations in patients with type 2 diabetes (DMt2) at early stages of diabetic kidney disease.

MATERIAL AND METHODS

The study included 115 DMt2 patients aged 60.0 ±15.5 years, with albuminuria < 300 mg/g creatinine and estimated glomerular filtration rate ≥ 60 ml/min/1.73 m² prospectively recruited at the nephrology ambulatory clinic in 2014-2015. The exclusion criteria were urinary tract infections (excluded by urine culture) and other diseases influencing uNGAL, including inflammatory and other kidney diseases. Urine concentrations of NGAL, albumin and creatinine were measured in the first morning samples, and the urine albumin to creatinine ratio (UACR) and uNGAL to creatinine ratio (UNCR) were calculated. Leukocyturia was detected microscopically.

RESULTS

Sterile leukocyturia was present in 15% (95% confidence interval: 9-23%) of patients. Patients with leukocyturia had higher uNGAL and UNCR than patients without leukocyturia. ln(UNCR) correlated with ln(UACR) in the whole group (R = 0.59; p < 0.001) and in patients without leukocyturia (R = 0.56; p < 0.001). In multiple regression, age, ln(UACR), ln(HbA1c) and leukocyturia were independent positive predictors of ln(UNCR). Among patients with leukocyturia, the associations of UNCR with UACR, age and HbA1c were non-significant.

CONCLUSIONS

In patients with DMt2, the presence of sterile leukocyturia coexists with increased uNGAL and UNCR. Leukocyturia interferes with the relationship between UNCR and UACR or HbA1c.

Cardiovascular safety of non-insulin pharmacotherapy for type 2 diabetes

Patients with type 2 diabetes mellitus have a twofold increased risk of cardiovascular mortality compared with non-diabetic individuals. There is a growing awareness that glycemic efficacy of anti-diabetic drugs does not necessarily translate to cardiovascular safety. Over the past few years, there has been a number of trials evaluating the cardiovascular effects of anti-diabetic drugs. In this review, we seek to examine the cardiovascular safety of these agents in major published trials. Metformin has with-stood the test of time and remains the initial drug of choice. The sulfonylureas, despite being the oldest oral anti-diabetic drug, has been linked to adverse cardiovascular events and are gradually being out-classed by the various other second-line agents. The glitazones are contraindicated in heart failure. The incretin-based drugs have been at the fore-front of this era of cardiovascular safety trials and their performances have been reassuring, whereas the meglitinides and the alpha-glucosidase inhibitors still lack cardiovascular outcomes data. The sodium glucose cotransporter-2 inhibitors are an exciting new addition that has demonstrated a potential for cardiovascular benefit. Many of the currently available oral anti-diabetic agents have clinically relevant cardiovascular effects. The optimal approach to the reduction of cardiovascular risk in diabetic patients should focus on aggressive management of the standard cardiovascular risk factors rather than purely on intensive glycemic control.

Antidiabetic Effect of Brain-Derived Neurotrophic Factor and Its Association with Inflammation in Type 2 Diabetes Mellitus

Brain-derived neurotrophic factor (BDNF) is a neurotrophin, which plays an important role in the central nervous system, and systemic or peripheral inflammatory conditions, such as acute coronary syndrome and type 2 diabetes mellitus (T2DM). BDNF is also expressed in several nonneuronal tissues, and platelets are the major source of peripheral BDNF. Here, we reviewed the potential role of BDNF in platelet reactivity in T2DM and its association with selected inflammatory and platelet activation mediators. Besides that, we focused on adipocytokines such as leptin, resistin, and adiponectin which are considered to take part in inflammation and both lipid and glucose metabolism in diabetic patients as previous studies showed the relation between adipocytokines and BDNF. We also reviewed the evidences of the antidiabetic effect of BDNF and the association with circulating inflammatory cytokines in T2DM.

Pharmacogenetic studies update in type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a silent progressive polygenic metabolic disorder resulting from ineffective insulin cascading in the body. World-wide, about 415 million people are suffering from T2DM with a projected rise to 642 million in 2040. T2DM is treated with several classes of oral antidiabetic drugs (OADs) viz. biguanides, sulfonylureas, thiazolidinediones, meglitinides, etc. Treatment strategies for T2DM are to minimize long-term micro and macro vascular complications by achieving an optimized glycemic control. Genetic variations in the human genome not only disclose the risk of T2DM development but also predict the personalized response to drug therapy. Inter-individual variability in response to OADs is due to polymorphisms in genes encoding drug receptors, transporters, and metabolizing enzymes for example, genetic variants in solute carrier transporters (SLC22A1, SLC22A2, SLC22A3, SLC47A1 and SLC47A2) are actively involved in glycemic/HbA1c management of metformin. In addition, CYP gene encoding Cytochrome P450 enzymes also play a crucial role with respect to metabolism of drugs. Pharmacogenetic studies provide insights on the relationship between individual genetic variants and variable therapeutic outcomes of various OADs. Clinical utility of pharmacogenetic study is to predict the therapeutic dose of various OADs on individual basis. Pharmacogenetics therefore, is a step towards personalized medicine which will greatly improve the efficacy of diabetes treatment.

Is gliclazide a sulfonylurea with difference? A review in 2016

Sulfonylureas (SUs) remain the most commonly prescribed drug after metformin in the treatment of type 2 diabetes (T2DM), despite the availability of several newer agents. The primary reason of SUs being most popular is their quick glycemic response, time-tested experience and least cost. Although SUs are one amongst the several other second line agents after metformin in all major guidelines, the new Dutch type 2 guidelines specifically advise gliclazide as the preferred second line drug instead of SUs as a class. The World Health Organization (WHO) has also included gliclazide in their Model List of Essential Medicines 2013 motivated by its safety data in elderly patients. Specifically advising gliclazide may have been based on emerging evidence suggesting cardiovascular neutrality of gliclazide over other SUs. This prompted us to do a literature review of gliclazide efficacy and safety data compared to other SUs as well as oral anti-diabetic drugs.