Glibenclamide-associated hypoglycaemia: a report on 57 cases

Apigenin potentiates glucose-stimulated insulin secretion through the PKA-MEK kinase signaling pathway independent of K-ATP channels

AIM

Apigenin, a natural bioflavonoid, is reported as an anti-diabetic agent since it possesses the ability to inhibit α-glucosidase activity, cause stimulation of insulin action and secretion, manage ROS, and prevent diabetes complications. Apigenin was identified as a new insulin secretagogue that enhances glucose-stimulated insulin secretion and seems like a better antidiabetic drug candidate. Here we explored the insulinotropic mechanism(s) of apigenin in vitro in mice islets and in vivo in diabetic rats.

METHODS

Size-matched pancreatic islets were divided into groups and incubated in the presence or absence of apigenin and agonists or antagonists of major insulin signaling pathways. The secreted insulin was measured by ELISA. The intracellular cAMP was estimated by cAMP acetylation assay. The acute and chronic effects of apigenin were evaluated in diabetic rats.

RESULTS

apigenin dose-dependently enhanced insulin secretion in isolated mice islets, and its insulinotropic effect was exerted at high glucose concentrations distinctly different from glibenclamide. Furthermore, apigenin amplified glucose-induced insulin secretion in depolarized and glibenclamide-treated islets. Apigenin showed no effect on intracellular cAMP concentration; however, an additive effect was observed by apigenin in both forskolin and IBMX-induced insulin secretion. Interestingly, H89, a PKA inhibitor, and U0126, a MEK kinase inhibitor, significantly inhibited apigenin-induced insulin secretion; however, no significant effect was observed by using ESI-05, an epac2 inhibitor. Apigenin improved glucose tolerance and increased glucose-stimulated plasma insulin levels in diabetic rats. Apigenin also lowered blood glucose in diabetic rats upon chronic treatment.

CONCLUSION

Apigenin exerts glucose-stimulated insulin secretion by modulating the PKA-MEK kinase signaling cascade independent of K-ATP channels.

Blocking Kir6.2 channels with SpTx1 potentiates glucose-stimulated insulin secretion from murine pancreatic β cells and lowers blood glucose in diabetic mice

ATP-sensitive K⁺ (K_ATP) channels in pancreatic β cells are comprised of pore-forming subunits (Kir6.2) and modulatory sulfonylurea receptor subunits (SUR1). The ATP sensitivity of these channels enables them to couple metabolic state to insulin secretion in β cells. Antidiabetic sulfonylureas such as glibenclamide target SUR1 and indirectly suppress Kir6.2 activity. Glibenclamide acts as both a primary and a secondary secretagogue to trigger insulin secretion and potentiate glucose-stimulated insulin secretion, respectively. We tested whether blocking Kir6.2 itself causes the same effects as glibenclamide, and found that the Kir6.2 pore-blocking venom toxin SpTx1 acts as a strong secondary, but not a strong primary, secretagogue. SpTx1 triggered a transient rise of plasma insulin and lowered the elevated blood glucose of diabetic mice overexpressing Kir6.2 but did not affect those of nondiabetic mice. This proof-of-concept study suggests that blocking Kir6.2 may serve as an effective treatment for diabetes and other diseases stemming from K_ATP hyperactivity that cannot be adequately suppressed with sulfonylureas.

Continuous adsorptive removal of glimepiride using multi-walled carbon nanotubes in fixed-bed column

Water pollution by emerging pollutants such as pharmaceutical and personal care products is one of today's biggest challenges. The presence of these emerging contaminants in water has raised increasing concern due to their frequent appearance and persistence in the aquatic ecosystem and threat to health and safety. The antidiabetic drug glimepiride, GPD, is among these compounds, and it possesses adverse effects on human health if not carefully administered. Several conventional processes were proposed for the elimination of these persistent contaminants, and adsorption is among them. Therefore, in this study, the adsorptive removal of GPD from water using multi-walled carbon nanotubes (MWCNT) supported on silica was explored on a fixed-bed column. The effects of bed-height, solution pH, and flow rate on the adsorptive removal of GPD were investigated. The obtained adsorption parameters using Sips, Langmuir, and Freundlich models were used to investigate the continuous adsorption. The results showed that the drug removal is improved with the increasing bed height; however, it decreased with the flow rate. The effect of pH indicated that the adsorption is significantly affected and increased in acidic medium. The convection-dispersion model coupled with Freundlich isotherm was developed and used to describe the adsorption breakthrough curves. The maximum adsorption capacity (q_m) was 275.3 mg/g, and the axial dispersion coefficients were ranged between 3.5 and 9.0 × 10⁵ m²/s. The spent adsorbent was successfully regenerated at high pH by flushing with NaOH.

Hypoglycemia and Glycemic Control With Glyburide in Women With Gestational Diabetes and Genetic Variants of Cytochrome P450 2C9 and/or OATP1B3

Glyburide is mainly metabolized by the cytochrome P450 2C9 (CYP2C9) enzyme and enters the liver via the transporter OATP1B3. The variants OATP1B3*4 (699 G>A; rs7311358) and CYP2C9*2 and *3 are known to have a significant influence on the hepatic uptake and metabolism of glyburide, with lower clearance than in the wild type. In an ancillary study of the INDAO trial, we selected 117 pregnant women with gestational diabetes treated by glyburide and assessed the role of the combined CYP2C9 and OATP1B3 genetic polymorphisms in hypoglycemia and glycemic control. Three groups were constituted: (1) the wild-type genotype group (wild-type allele genotype for both CYP2C9*1 and OATP1B3*1 (699G)), (2) the intermediate group (carriers of CYP2C9*2 allele or OATP1B3*4 (699G>A) heterozygous), and (3) the variant group (carriers of CYP2C9*3 allele and/or OATP1B3*4 (699G>A) homozygous variant). We found that the risk of hypoglycemia was significantly higher in the variant genotype at the second week of treatment: 20.0% (4/20) vs. 8.1% (3/37) in the intermediate group and 4.1% (2/49) in the wild-type genotype group (P = 0.03). The last daily dose of glyburide during pregnancy was lower for patients in the variant genotype group: 4.7 mg (SD 3.5) vs. 8.7 mg (SD 5.7) in the wild-type group and 5.7 mg (SD 3.7) in the intermediate group (P < 0.01). In conclusion, the no-function variants CYP2C9*3 and OATP1B3*4 are associated with a higher risk of hypoglycemia and a lower dose of glyburide in women with gestational diabetes treated with glyburide, which is consistent with the pharmacokinetic roles of both CYP2C9 and OATP1B3.

Hypoglycemic and Antihyperglycemic Activities of 80% Methanol Root Extract of Acanthus polystachyus Delile (Acanthaceae) in Type 2 Diabetic Rats

Background

The morbidity and mortality rate from diabetic mellitus are increasing in the world especially in low- and middle-income countries; hence, it is necessary to evaluate the efficacy and safety of medicinal plants to support existing drugs in treating diabetes mellitus. Therefore, the aim of this study was to evaluate the hypoglycemic effect of 80% methanol root extract of Acanthus polystachyus in normoglycemic, hyperglycemic, and streptozotocin–nicotinamide induced diabetic rats.

Methods

Male albino Wistar rats were divided into five groups (n=6) in all three models. In all models, group one rats served as a negative control and were received vehicle (10mL/kg distilled water), whereas group two (APRE100), three (APRE200), and four (APRE400) were treated with 100, 200, and 400mg/kg of extract, respectively, and group five were treated with glibenclamide (5mg/kg) and served as a positive control. Blood glucose levels were measured at different time points by taking blood from their tails. Data were analyzed using one-way ANOVA followed by Tukey’s post hoc test to carry out comparisons between and within-group and P < 0.05 was considered as statistically significant.

Results

The root of Acanthus polystachyus reduces peak blood sugar levels significantly after the loading of oral glucose at all tested doses. In streptozotocin–nicotinamide-induced type 2 diabetic rats, the daily oral administration of the crude extracts showed a significant reduction of blood glucose level at all tested doses compared to the negative control group. However, the extract did not reduce blood glucose levels in normoglycemic rats at all tested doses compared to both negative and positive control.

Conclusion

From this study, it can be concluded that the root extract of Acanthus polystachyus showed an antihyperglycemic effect in hyperglycemic and diabetic rats but lack hypoglycemic effect in normoglycemic rats. Hence, the plant root may be a good candidate for the development of new antidiabetic drugs.

Screening for Sulphonylureas in the Investigation of Hypoglycaemia

The most important cause of hypoglycaemia in the presence of high insulin and C-peptide concentrations is insulinoma. However, a similar picture arises from use of sulphonylureas, which is sometimes covert. All specimens received in two years by a supraregional assay service laboratory from adults with low glucose and inappropriately high insulin and C-peptide concentrations were tested for sulphonylureas by a radioimmunoassay that employed antibodies to glibenclamide. In sulphonylurea-positive cases a questionnaire was sent to the consultant responsible for the patient, to elicit further information.

Samples from 93 adult patients met the criteria, and 34 (37%) of these gave a positive result on screening for sulphonylureas. The consultants provided further information on 31 of the 34, and in 20 the presence of a sulphonylurea was unexpected. In 10 the features were such as to raise the possibility of factitious drug ingestion.

A simple screening technique applied to specimens from patients with hyperinsulinaemic hypoglycaemia indicated that, in a substantial proportion of cases, the patient was taking a sulphonylurea.

Transporter-Mediated Disposition, Clinical Pharmacokinetics and Cholestatic Potential of Glyburide and Its Primary Active Metabolites

Glyburide is widely used for the treatment of type 2 diabetes. We studied the mechanisms involved in the disposition of glyburide and its pharmacologically active hydroxy metabolites M1 and M2b and evaluated their clinical pharmacokinetics and the potential role in glyburide-induced cholestasis employing physiologically based pharmacokinetic (PBPK) modeling. Transport studies of parent and metabolites in human hepatocytes and transfected cell systems imply hepatic uptake mediated by organic anion-transporting polypeptides. Metabolites are also subjected to basolateral and biliary efflux by P-glycoprotein, breast cancer resistance protein, and multidrug resistance-associated proteins, and are substrates to renal organic anion transporter 3. A PBPK model in combination with a Bayesian approach was developed considering the identified disposition mechanisms. The model reasonably described plasma concentration time profiles and urinary recoveries of glyburide and the metabolites, implying the role of multiple transport processes in their pharmacokinetics. Predicted free liver concentrations of the parent (∼30-fold) and metabolites (∼4-fold) were higher than their free plasma concentrations. Finally, all three compounds showed bile salt export pump inhibition in vitro; however, significant in vivo inhibition was not apparent for any compound on the basis of a predicted unbound liver exposure-response effect model using measured in vitro IC₅₀ values. In conclusion, this study demonstrates the important role of multiple drug transporters in the disposition of glyburide and its active metabolites, suggesting that variability in the function of these processes may lead to pharmacokinetic variability in the parent and the metabolites, potentially translating to pharmacodynamic variability.

Secular Trends in the Clinical Characteristics of Type 2 Diabetic Patients With Severe Hypoglycemia Between 2008 and 2013

Background

We investigated the trends in the clinical characteristics and prescriptions of type 2 diabetic patients with severe hypoglycemia because the prescription rate of antidiabetic agents has significantly changed recently.

Methods

A total of 193 patients with type 2 diabetes with severe hypoglycemia induced by antidiabetic agents between 2008 and 2013 were divided into three groups based on the period of visit: 2008 - 2009, 2010 - 2011 and 2012 - 2013.

Results

While the proportion of patients with severe hypoglycemia using insulin (from 55% to 74%), biguanides (from 6% to 20%), glinides, and dipeptidyl peptidase-4 inhibitors significantly increased, those using sulfonylureas (from 45% to 20%) significantly decreased. Errors of drug use significantly increased as a trigger of hypoglycemia in recent years. The number of antidiabetic agents (from 1.9 ± 0.6 to 2.3 ± 0.7), non-diabetic agents (from 2.3 ± 2.4 to 4.3 ± 3.3), and total drugs prescribed were significantly higher in recent years among patients receiving insulin therapy.

Conclusions

Polypharmacy especially in patients receiving insulin therapy and errors of drug use have increased in type 2 diabetic patients with severe hypoglycemia in recent years. Intensive education in the usage rule of drugs is considered to be important in order to prevent severe hypoglycemia.

Glibenclamide-induced profound hypoglycaemic crisis: a case report

The value of sulphonylureas in the long-term treatment of type II diabetes has been questioned. The potential benefits of an antidiabetic drug must be carefully weighed against the risk of developing hazardous adverse effects like hypoglycaemia. We present drug-induced hypoglycaemia in a 77-year-old Pakistani male who had hypertension, type II diabetes and renal parenchymal disease (grade I), presented to the emergency department complaining of a 1-day history of fever, loose motions and drowsiness. His fever was low grade, intermittent, and not associated with rigors and chills. He had four episodes of watery stools for 1 day, with no associated vomiting but with drowsiness. He was aphasic, unable to walk and did not recognize his family members. The patient was taken to his local doctor who found him to be hypoglycaemic, with a blood sugar of 45 mg/dl. He was managed with intravenous (IV) dextrose and referred to the hospital. Hypoglycaemia is perhaps the most widespread and underreported complication of oral hypoglycaemic agents and may lead to overwhelming morbidity and mortality. Patient evaluation and proper counselling may help in identifying patients at greatest risk and avoid complications associated with these commonly prescribed drugs.

Causative anti-diabetic drugs and the underlying clinical factors for hypoglycemia in patients with diabetes

Recent clinical trials indicated that the intensive glycemic control do not reduce cardiovascular disease mortality among diabetic patients, challenging a significance of the strict glycemic control in diabetes management. Furthermore, retrospective analysis of the Action to Control Cardiovascular Risk in Diabetes study demonstrated a significant association between hypoglycemia and mortality. Here, we systematically reviewed the drug-induced hypoglycemia, and also the underlying clinical factors for hypoglycemia in patients with diabetes. The sulfonylurea use is significantly associated with severe hypoglycemia in patients with type 2 diabetes. The use of biguanide (approximately 45%-76%) and thiazolidinediones (approximately 15%-34%) are also highly associated with the development of severe hypoglycemia. In patients treated with insulin, the intensified insulin therapy is more frequently associated with severe hypoglycemia than the conventional insulin therapy and continuous subcutaneous insulin infusion. Among the underlying clinical factors for development of severe hypoglycemia, low socioeconomic status, aging, longer duration of diabetes, high HbA1c and low body mass index, comorbidities are precipitating factors for severe hypoglycemia. Poor cognitive and mental functions are also associated with severe hypoglycemia.

Increasing awareness of hypoglycaemia in patients with type 2 diabetes treated with oral agents

Hypoglycaemia is the most common acute complication of type 2 diabetes and can limit therapeutic efforts to improve glycaemic control in order to protect against long-term complications. It is a potential side effect of the drugs used to treat diabetes, specifically exogenous insulin or insulin secretagogues. As many people are prescribed these agents, hypoglycaemia is frequent in clinical practice, although patients commonly do not inform their healthcare professional of the problems spontaneously. The impact of hypoglycaemia on the patient and to the healthcare system is significant through reduced treatment satisfaction and adherence, reduced quality of life and serious health consequences. This has financial implications and costs for the patient, the public and the economy at large. The single most important risk factor for hypoglycaemia is previous hypoglycaemia. Prevention depends on appropriate education regarding diabetes management and selfcare, self-monitoring of blood glucose, awareness of factors that may precipitate hypoglycaemia, and an individualized approach to therapy and glycaemic control targets. The purpose of this review is to increase understanding of the impact and consequences of hypoglycaemia, in particular that associated with sulphonylurea therapy, and to highlight areas requiring more attention in order to improve the overall management of people with type 2 diabetes.

Cardiovascular disease and oral agent glucose-lowering therapies in the management of type 2 diabetes

Although glucose-lowering oral agents have been available for clinical use for over 60 years, the formal evidence base supporting their advantage and safety in regard of cardiovascular (CV) outcomes remains less than optimal. However, a synthesis of the evidence results in a high probability of benefit. For metformin, the United Kingdom Prospective Diabetes Study (UKPDS) substudy is convincing for a definite effect in reducing myocardial infarction (MI), but the quantitative extent of that is uncertain. For sulfonylureas, support for reduction in MI comes from the UKPDS extension study, where the central estimate for risk reduction remains the same as in the original planned end to the study, but the greater number of events was statistically significant for the sulfonylurea/insulin arm. Other studies do not support the view that metformin and sulfonylureas differ with respect to MI or indeed CV outcomes more generally. The data available for acarbose, an α-glucosidase inhibitor, are weak but not of concern, although some positive substudy data are available for people with impaired glucose tolerance. For peroxisome proliferator-activated receptor-γ agonists the CV data are more controversial, but the purpose-designed randomized controlled trials are clear that pioglitazone is advantageous to placebo (except for heart failure [HF]), whereas rosiglitazone is indistinguishable from metformin/sulfonylureas (even when including HF data). Lower-quality data do, however, lead to significant concerns for MI with rosiglitazone. Early and somewhat low-quality data for the dipeptidyl peptidase inhibitors show they are safe and hold promise for cardiovascular advantage, with major randomized controlled trials being underway. Preliminary CV data are available for one sodium/glucose cotransporter 2 inhibitor and look reassuring.

Discovery of phenylpropanoic acid derivatives containing polar functionalities as potent and orally bioavailable G protein-coupled receptor 40 agonists for the treatment of type 2 diabetes

As part of a program to identify potent GPR40 agonists with drug-like properties suitable for clinical development, the incorporation of polar substituents was explored with the intention of decreasing the lipophilicity of our recently disclosed phenylpropanoic acid derivative 1. This incorporation would allow us to mitigate the cytotoxicity issues observed with compound 1 and enable us to move away from the multifunctional free fatty acid-like structure. Substitutions on the 2',6'-dimethylbiphenyl ring were initially undertaken, which revealed the feasibility of introducing polar functionalities at the biphenyl 4'-position. Further optimization of this position and the linker led to the discovery of several 4'-alkoxybiphenyl derivatives, which showed potent GPR40 agonist activities with the best balance in terms of improved cytotoxicity profiles and favorable pharmacokinetic properties. Among them, 3-{2-fluoro-4-[({4'-[(4-hydroxy-1,1-dioxidotetrahydro-2H-thiopyran-4-yl)methoxy]-2',6'-dimethylbiphenyl-3-yl}methyl)amino]phenyl}propanoic acid (35) exhibited a robust plasma glucose-lowering effect and insulinotropic action during an oral glucose tolerance test in rats with impaired glucose tolerance.

[Diabetes in the elderly]

One third of the population above 70 has a diabetic-like metabolic status. Diabetes-induced diseases as well as acute blood sugar imbalances have great impact on quality of life. Transferring the known disease management regimes from adults to the elderly is only possible to a limited extent. For patients needing short-term or long-term care, the clinical practical guidelines should, therefore, be adapted to the medical care situation. The favored live-style modification with change of nutrition or increased activity is limited by multimorbidity in the elderly. Medical therapy should be adjusted to 6.6-10.0 (11.1) mmol/l glucose. Hypoglycemia must be avoided, whereas elderly patients with HbA(1c) values above 8% also requires insulin treatment. Simple treatment and the involvement of family members or informal caregivers are the basis of good diabetes treatment in old patients.

Mild hypoglycaemic attacks induced by sulphonylureas related to CYP2C9, CYP2C19 and CYP2C8 polymorphisms in routine clinical setting

AIM

To evaluate the impact of polymorphisms in the cytochrome P450 (CYP) 2C9, 2C19 and 2C8 genes on the risk of mild hypoglycaemic attacks in patients treated with sulphonylureas.

METHODS

One hundred and eight type 2 diabetic patients (50 men, 58 women), treated with oral antidiabetics, including at least one from the sulphonylurea group (glimepiride n = 50, gliclazide n = 46, or glipizide n = 12) for 3 months or longer, were included in the study. Symptoms of hypoglycaemia (sweating, tremor, anxiety and palpitations) during a 3 month period were recorded and confirmed by home glucose measurements. Gender, age, body mass index, creatinine clearance, HbA1c, oral antidiabetic dose and concomitant medication were assessed together with functional CYP2C9, CYP2C19 and CYP2C8 polymorphisms, analysed by real-time PCR methods.

RESULTS

Fifteen patients (eight men, seven women) reported hypoglycaemia symptoms which were validated by their home glucose measurements (< 70 mg/dl). Heterozygosity and homozygosity for CYP2C9 variant alleles (*2 or *3) tended to be more frequent among patients who reported hypoglycaemic attacks (60 and 7%) than those who did not (39 and 3%). Similarly, the CYP2C8*1/*3 genotype tended to be more frequent in patients with (47%) than without (27%) hypoglycaemia, while no such trend was observed for CYP2C19 variants. However, only in the gliclazide group a significant association between CYP2C9 genotype and hypoglycaemic attacks was observed (P = 0.035). None of the other covariates showed any significant association with the risk of hypoglycaemic attacks.

CONCLUSIONS

CYP2C9 polymorphisms leading to decreased enzyme activity show a modest impact on the risk of mild hypoglycaemia attacks during oral antidiabetic treatment, with a significant association in patients treated with gliclazide.

Influence of CYP2C9 gene polymorphisms on response to glibenclamide in type 2 diabetes mellitus patients

PURPOSE

The antidiabetic drug glibenclamide is metabolized by the enzyme cytochrome P450 2C9 (CYP2C9) encoded by the polymorphic gene CYP2C9. Previous studies involving healthy volunteers have shown a significant influence of variant CYP2C9 genotypes on glibenclamide metabolism. The aim of this study was to investigate the influence of genetic polymorphisms of CYP2C9 on the response to glibenclamide and on glibenclamide plasma levels in type 2 diabetes mellitus patients.

METHODS

The study cohort consisted of type 2 diabetes mellitus patients (n = 80) on regular therapy with glibenclamide either alone or with concomitant metformin. Plasma levels of glibenclamide were estimated by reverse phase high pressure liquid chromatography. The variant alleles of CYP2C9, namely CYP2C9 *2 and *3, were identified by PCR-restricted fragment length polymorphism. The plasma levels of glibenclamide and occurrences of hypoglycemic adverse effects with their severity were compared between the genotype groups.

RESULTS

Of the 80 patients (61 males, 19 females), 78 were on concomitant treatment with two drugs, namely, glibenclamide and metformin, and two were on monotherapy with glibenclamide. There was a significant association (p < 0.001) between genotype status of CYP2C9 and the control of diabetes in patients receiving treatment with glibenclamide. There were no statistically significant differences in hypoglycemic adverse effects between the genotype groups.

CONCLUSION

The type 2 diabetes mellitus patients participating in this study with variant genotypes of CYP2C9 were found to respond better to treatment with glibenclamide than those with the normal genotype. The variant genotype CYP2C9 *1/*3 did not significantly influence the hypoglycemic adverse effects among those patients on long-term glibenclamide treatment.

Severe sulfonylurea-induced hypoglycemia: a problem of uncritical prescription and deficiencies of diabetes care in geriatric patients

OBJECTIVE

Severe sulfonylurea-induced hypoglycemia (SH) remains a life-threatening and under-reported condition. We investigated the incidence of SH and clinical characteristics of patients with type 2 diabetes mellitus (T2DM) to demonstrate typical risk constellations.

METHODS

In a prospective population-based observational study, all consecutive cases of SH in the period 2000 - 2009 in a German area with 200,000 inhabitants were registered. Severe hypoglycemia was defined as a symptomatic event requiring treatment with intravenous glucose and was confirmed by a blood glucose measurement of < 50 mg/dl.

RESULTS

A mean incidence of seven episodes of SH per year and 100,000 inhabitants was registered. The 139 hypoglycemic individuals had been treated with glimepiride (n = 98), glibenclamide (n = 40) or gliquidone (n = 1). No preparation showed a constant dose-effect relationship, SH occurring within a wide dose range. The patients were characterized as follows: age 77.5 + or - 9.4 years, duration of diabetes 11 + or - 7 years, body mass index 26.3 + or - 4.9 kg/m(2), HbA1c 6.6 + or - 1.3%, creatinine clearance 46 + or - 24 ml/min with renal insufficiency in 73% and co-medication 7 + or - 3 drugs. Two-thirds of all subjects lived independently at home whereas a third were cared for by a home nursing service or received care in nursing homes. In all, 30% had participated in diabetes education programs. In 31%, systematic blood glucose monitoring was performed.

CONCLUSIONS

Uncritical prescription of sulfonylureas neglecting crucial contraindications - particularly renal insufficiency - and deficiencies of diabetes care contributed substantially to the risk of SH in the mainly geriatric patients. There is a need for alternative therapeutic concepts that minimize the risk of hypoglycemia in geriatric patients with T2DM.

Comparison of antioxidant effects of honey, glibenclamide, metformin, and their combinations in the kidneys of streptozotocin-induced diabetic rats

Hyperglycemia-induced increase in oxidative stress is implicated in diabetic complications. This study investigated the effect of metformin and/or glibenclamide in combination with honey on antioxidant enzymes and oxidative stress markers in the kidneys of streptozotocin (60 mg/kg; intraperitoneal)-induced diabetic rats. Diabetic rats were randomized into eight groups of five to seven rats and received distilled water (0.5 mL); honey (1.0 g/kg); metformin (100 mg/kg); metformin (100 mg/kg) and honey (1.0 g/kg); glibenclamide (0.6 mg/kg); glibenclamide (0.6 mg/kg) and honey (1.0 g/kg); metformin (100 mg/kg) and glibenclamide (0.6 mg/kg); or metformin (100 mg/kg), glibenclamide (0.6 mg/kg) and honey (1.0 g/kg) orally once daily for four weeks. Malondialdehyde (MDA) levels, glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities were significantly elevated while catalase (CAT) activity, total antioxidant status (TAS), reduced glutathione (GSH), and GSH:oxidized glutathione (GSSG) ratio was significantly reduced in the diabetic kidneys. CAT, glutathione reductase (GR), TAS, and GSH remained significantly reduced in the diabetic rats treated with metformin and/or glibenclamide. In contrast, metformin or glibenclamide combined with honey significantly increased CAT, GR, TAS, and GSH. These results suggest that combination of honey with metformin or glibenclamide might offer additional antioxidant effect to these drugs. This might reduce oxidative stress-mediated damage in diabetic kidneys.

Impact of clinical factors and CYP2C9 variants for the risk of severe sulfonylurea-induced hypoglycemia

AIMS

The established risk factors for severe sulfonylurea-induced hypoglycemia (SH) include low hemoglobin (Hb)A(1c), advanced age, long duration of diabetes, multimorbidity, and polypharmacy. As the genetically polymorphic cytochrome P450 (CYP), enzyme CYP2C9 is mainly responsible for the hepatic metabolism of sulfonylureas (SUs), we hypothesized that the slow-metabolizer genotypes *2/*2, *2/*3, and *3/*3 might be overrepresented in type 2 diabetic patients with SH.

METHODS

In a prospective population-based case-control study, CYP2C9 allelic variants of 102 diabetic patients with SH were compared with a matched group of 101 SU-treated patients without a history of SH. The 203 Caucasian patients had been treated with the SUs glimepiride, glibenclamide, or gliquidone. SH was defined as a symptomatic event requiring treatment with intravenously administered glucose and was confirmed by a blood glucose measurement of <50 mg/dl (<2.8 mmol/l). As two control groups, we selected 337 Caucasian diabetic patients receiving antidiabetic drugs per os and 1,988 healthy Caucasian volunteers who had been genotyped earlier.

RESULTS

In the univariate analysis, only a low HbA(1c) value (p = 0.0004) was shown as a risk factor for SH. There was no overrepresentation of the CYP2C9 *2/*2, *2/*3, and *3/*3 variants in the SH group (2%) compared with the control group (5%). However, in the control group, patients with CYP2C9 genotypes, predicting slower metabolism of SU drugs, were treated with significantly lower doses (p = 0.027) than were extensive metabolizers, whereas in the patient group with severe hypoglycemia, the dose was the same for all genotype groups.

CONCLUSIONS

In the present cohort of 102 patients with SH, a low HbA(1c) value was related to the risk for SH. There was no overrepresentation observed of the CYP2C9 slow-metabolizer genotypes in the hypoglycemic patients group, but the drug exposure in the slow-metabolizer genotypes was estimated to be higher in hypoglycemic patients, which might partly have contributed to their risk for SH.

Self-monitoring of blood glucose in diabetes mellitus: arguments for an individualized approach

BACKGROUND

The utility of glucose self-monitoring in different types and stages of diabetes is controversial, as there is only sparse relevant evidence from randomized controlled clinical trials. In this analysis, the authors aim to develop individualized recommendations based on clinical needs and the available literature.

METHODS

The PubMed database was searched for articles that appeared up to 30 September 2008 containing the terms "measurement," "control","monitoring," and "hypoglycemia"; the retrieved articles were supplemented by other articles that were cited in them. A directed search was also made for the recommendations of the German, European, American, and international diabetological societies. Conclusions were then drawn about the useful modalities and extent of glucose self-monitoring on the basis of the clinical features of the major types of diabetes and the main treatment strategies for them.

RESULTS

With the exception of intensified treatment strategies (which rely on blood-sugar regulation with insulin), only a few evidence-based recommendations can be derived from randomized clinical trials and meta-analyses. Nonetheless, a strategy for self-monitoring according to the patient's individual needs can be derived from the characteristics of therapeutic regimens: depending on the type of diabetes from which the patient suffers, the predicted number of glucometer strips required for self-monitoring will vary from almost none to roughly 400 per month.

CONCLUSIONS

The decision to use glucose self-monitoring, as well as the type and extent of self-monitoring that will be used, should be based on the individual patient's type of diabetes, treatment regimen, and clinical characteristics. Like any other type of therapeutic intervention, self-monitoring should have a well-documented, rational justification.

Drug utilization and morbidity statistics for the evaluation of drug safety in Sweden

For a continuous monitoring and evaluation of drug safety problems in Sweden, the Department of Drugs of the National Board of Health and Welfare has access to a number of computerised patient-, drug-, and disease-oriented registers. The usefulness and limitations of these registers are presented by examples. A recent increase in asthma deaths is presently being analysed by comparing information from death certificates and case records with drug sales and prescription data. A recent analysis of the cancer register showed no increased risk of malignant thyroid tumors after diagnostic or therapeutic doses of I 131. Similarly no increased risk of malformations after occupational exposure to hexachlorophene could be detected by analysing the malformation and medical birth-record registers in relation to hospital hexachlorophene use. The register of patient discharge diagnoses has been repeatedly used to analyse the incidence and pattern of drug induced blood dyscrasias and thromboembolism associated with oral contraceptives (OC). These analyses have resulted i.a. in the withdrawal of dipyrone and tenalidine and a decrease of the estrogen-content of OCs. At the same time about 1/3 of these serious adverse drug reactions (ADR) was found to have been reported to the ADR-register. By combining sales and prescription data with ADR-reports the risk of inducing lactic acidosis was found to be significantly higher for phenformin than for metformin. Also the incidence of tardive dyskinesia from longterm use of metoclopramide was found to be much higher than hitherto recognized. By use of these registers it is possible to obtain valuable information about the safety of drugs. The raw data must, however, be interpreted with care and often be supplemented with in depth studies of the various problems.

Antidiabetic effects of dipeptidyl peptidase-IV inhibitors and sulfonylureas in streptozotocin-nicotinamide-induced mildly diabetic mice

The present study investigated the antidiabetic effects of the dipeptidyl peptidase (DPP)-IV inhibitors ASP8497 and vildagliptin, and the sulfonylureas glibenclamide and gliclazide in streptozotocin-nicotinamide-induced mildly diabetic mice. A single administration of ASP8497 and vildagliptin significantly improved glucose tolerance by increasing plasma insulin and glucagon-like peptide-1 levels. In addition, a single administration of glibenclamide and gliclazide also caused significant improvement in glucose tolerance with an accompanying increase in the plasma insulin level. Subsequently, the effects of a 1-week chronic daily dosing of DPP-IV inhibitors and sulfonylureas were investigated. All drugs significantly improved glucose tolerance on day 1 of chronic daily dosing. After 1 week of chronic daily dosing, the DPP-IV inhibitors caused a significant improvement in glucose tolerance similar to those observed on day 1 by increasing the plasma insulin and glucagon-like peptide-1 levels. In contrast, the sulfonylureas had no significant improving or insulinotropic effect. Furthermore, ASP8497 also had an antihyperglycemic effect and improved pancreatic histopathologic lesions in a 4-week chronic daily dosing study. These results suggest that chronic daily dosing of sulfonylureas had virtually no antidiabetic effects because of marked attenuation of the insulinotropic action in streptozotocin-nicotinamide-induced mildly diabetic mice. In contrast, the antidiabetic efficacy of DPP-IV inhibitors, including ASP8497, did not change even after chronic daily dosing; therefore, DPP-IV inhibitors are useful as a therapeutic agent for impaired glucose tolerance and type 2 diabetes mellitus.

Practical strategies to normalize hyperglycemia without undue hypoglycemia in type 2 diabetes mellitus

Hypoglycemia is a common problem in pharmacologically treated patients with type 2 diabetes mellitus and can be a major barrier to achieving optimal glycemic control. For practitioners to minimize and treat hypoglycemia, it is important to understand the physiology, risk factors, and medications associated with hypoglycemia. Through education, lifestyle modifications, medication adjustments, and possibly re-examining glycemic goals, practitioners can reduce the incidence of hypoglycemia while still decreasing the risk of microvascular complications associated with hyperglycemia.

Chronic inhibition of dipeptidyl peptidase-IV with ASP8497 improved the HbA(1c) level, glucose intolerance, and lipid parameter level in streptozotocin-nicotinamide-induced diabetic mice

Dipeptidyl peptidase-IV (DPP-IV) is the primary inactivator of glucoregulatory incretin hormones, and DPP-IV inhibitors are expected to become a useful new class of anti-diabetic agent. The aim of the present study is to characterize the chronic in vivo profile of the DPP-IV inhibitor ASP8497. In streptozotocin-nicotinamide-induced diabetic mice, ASP8497 was administered orally for 3 weeks at 1, 3, or 10 mg/kg once daily, which improved the hemoglobin A(1c), non-fasting plasma insulin, fasting blood glucose levels, glucose intolerance, and lipid profiles (plasma triglyceride, non-esterified fatty acid and total cholesterol) with neutral effect on body weight. The pancreatic insulin content and hepatic phosphoenolpyruvate carboxykinase (PEPCK) activity recovered dose-dependently in ASP8497-treated groups. These results revealed that ASP8497 was successful in improving glycemic control and metabolic parameters in streptozotocin-nicotinamide-induced diabetic mice. It is therefore suggested that ASP8497 may be a potential agent for the treatment of type 2 diabetes.

The effect of sulphonylureas on the microvascular and macrovascular complications of diabetes

INTRODUCTION

Type 2 diabetes mellitus is a chronic progressive disease that is characterised by hyperglycaemia and is associated with an increased risk of the development of microvascular complications, such as retinopathy, nephropathy and neuropathy, and cardiovascular disease. With the introduction of newer oral hypoglycaemic agents, there is a need to re-evaluate critically the effectiveness and safety of the older agents, including sulphonylureas, to assess their place in the modern management of type 2 diabetes.

BACKGROUND

Though no clear benefit of sulphonylureas has been shown with respect to large vessel disease, long term studies have, however, shown benefits in patients with microvascular complications. Studies such as the University Group Diabetes Project raised concerns about the safety profile of sulphonylureas, but large prospective studies such as the UK Prospective Diabetes Study have helped to assuage such concerns to a large degree. Their utility in the peri-infarct period continues to be debatable because of the potential effect on cardiac pre-conditioning.

CONCLUSION

Though sulphonylureas continue to be a mainstay of treatment in type 2 diabetes, future clinical trials addressing clinically relevant outcomes are indicated with the newer generation of sulphonylureas that are more beta cell-specific to address the concerns raised about sulphonylureas and cardiac myocytes.

Ethanol acutely stimulates islet blood flow, amplifies insulin secretion, and induces hypoglycemia via nitric oxide and vagally mediated mechanisms

Hypoglycemia induced by alcohol ingestion is a well-known problem in diabetic patients. However, the mechanisms underlying this phenomenon have largely remained elusive. Because insulin secretion in vivo can be rapidly tuned by changes in pancreatic microcirculation, we evaluated the influence of acute alcohol administration on pancreatic islet blood flow (IBF), and dynamic changes in insulin secretion and glycemia in the rat. Ethanol (10%) or saline was iv injected as a bolus into Wistar rats, yielding serum ethanol concentrations of approximately 8 mmol/liter. Measurements of pancreatic blood flow (PBF) were performed by a microsphere technique in combination with a freeze-thawing technique after 10-min injection. Ethanol preferentially and significantly increased pancreatic IBF approximately 4-fold, whereas not influencing whole PBF. The alcohol also augmented late-phase insulin secretion and induced late hypoglycemia upon ip glucose tolerance tests. The nitric oxide synthase inhibitor N-w-nitro-L-arginine methyl ester and atropine prevented the increased pancreatic IBF, enhanced insulin secretion, and hypoglycemia evoked by ethanol. Thus, our findings demonstrate that ethanol acutely exerts substantial influences on pancreatic microcirculation by evoking a massive redistribution of PBF from the exocrine into the endocrine part via mechanisms mediated by nitric oxide and vagal stimuli, augmenting late-phase insulin secretion, and thereby evoking hypoglycemia. This effect may in part underlie the well-known hypoglycemic properties of alcohol in diabetic patients or in alcoholics with hepatic failure.

Diabetes and education in the elderly

Diabetes mellitus (DM) in the elderly is a chronic disease where self management is a key aspect. This includes lifestyle modification (diet and exercise), medication compliance and hypoglycaemia management. Education is an important part of this process and the specific needs of the older population with DM have been underlined. The literature has shown that education through a multidisciplinary approach may improve the glycaemic control in selected elderly patients with DM. This article will focus on the evidences from the medical literature and the multiple challenges of teaching in this population.

A systematic review and meta-analysis of hypoglycemia and cardiovascular events: a comparison of glyburide with other secretagogues and with insulin

OBJECTIVE

Glyburide is the most widely used sulfonylurea but has unique pharmacodynamic properties that may increase harm. We hypothesized that glyburide causes more hypoglycemia and cardiovascular events than other secretagogues or insulin.

RESEARCH DESIGN AND METHODS

Data sources were Medline, Embase, Cochrane, and three other web-based clinical trial registers (1966-2005). Parallel, randomized, controlled trials in people with type 2 diabetes comparing glyburide monotherapy with monotherapy using secretagogues or insulin were selected. Outcomes were hypoglycemia, glycemic control, cardiovascular events, body weight, and death. Titles and abstracts of 1,806 publications were reviewed in duplicate and 21 relevant articles identified. Data on patient characteristics, interventions, outcomes, and validity were extracted in duplicate using predefined criteria.

RESULTS

Glyburide was associated with a 52% greater risk of experiencing at least one episode of hypoglycemia compared with other secretagogues (relative risk 1.52 [95% CI 1.21-1.92]) and with 83% greater risk compared with other sulfonylureas (1.83 [1.35-2.49]). Glyburide was not associated with an increased risk of cardiovascular events (0.84 [0.56-1.26]), death (0.87 [0.70-1.07]), or end-of-trial weight (weighted mean difference 1.69 kg [95% CI -0.41 to 3.80]) compared with other secretagogues. Limitations included suboptimal reporting of original trials. Loss to follow-up exceeded 20% in some studies, and major hypoglycemia was infrequently reported.

CONCLUSIONS

Glyburide caused more hypoglycemia than other secretagogues and other sulfonylureas. Glyburide was not associated with an increased risk of cardiovascular events, death, or weight gain.

Hypoglycemia in Type 2 diabetic patients randomized to and maintained on monotherapy with diet, sulfonylurea, metformin, or insulin for 6 years from diagnosis: UKPDS73

The UK Prospective Diabetes Study (UKPDS) showed that a more intensive glucose control policy reduced risk of diabetic complications. As hypoglycemia is a barrier to achieving glycemic targets, we examined its occurrence and contributing factors in UKPDS patients randomized to and remaining for 6 years on diet, sulfonylurea, metformin (overweight subjects only), or insulin monotherapy from diagnosis of Type 2 diabetes. Self-reported hypoglycemic episodes were categorized as (1) transient, (2) temporarily incapacitated, (3) requiring third-party assistance, and (4) requiring medical attention, recording the most severe episode each quarter. Proportions of patients reporting at least one episode per year were calculated in relation to therapy, HbA(1c), and clinical characteristics. In 5063 patients aged 25-65 years, only 2.5% per year reported substantive hypoglycemia (Grades 2-4) and 0.55% major hypoglycemia (Grade 3 or 4). Hypoglycemia was more frequent in younger (4.0% <45 years vs. 2.2% >or=45 years), female (3.0% vs. 2.2% male), normal weight (3.6% body mass index <25 kg/m(2) vs. 1.9% >or=25 kg/m(2)), less hyperglycemic (5.2% HbA(1c) <7% vs. 2.3% >or=7%), or islet autoantibody-positive patients (4.3% vs. 2.1% negative) (all P<.0001). More on basal insulin reported hypoglycemia (3.8% per year) than diet (0.1%), sulfonylurea (1.2%), or metformin (0.3%) therapy, but less than on basal and prandial insulin (5.3%) (all P<.0001). Low hypoglycemia rates seen during the first 6 years of intensive glucose lowering therapy in Type 2 diabetes are unlikely to have a major impact on attempts to achieve guideline glycemic targets when sulfonylurea, metformin, or insulin are used as monotherapy.

Effect of genetic polymorphisms in cytochrome p450 (CYP) 2C9 and CYP2C8 on the pharmacokinetics of oral antidiabetic drugs: clinical relevance

Type 2 diabetes mellitus affects up to 8% of the adult population in Western countries. Treatment of this disease with oral antidiabetic drugs is characterised by considerable interindividual variability in pharmacokinetics, clinical efficacy and adverse effects. Genetic factors are known to contribute to individual differences in bioavailability, drug transport, metabolism and drug action. Only scarce data exist on the clinical implications of this genetic variability on adverse drug effects or clinical outcomes in patients taking oral antidiabetics. The polymorphic enzyme cytochrome P450 (CYP) 2C9 is the main enzyme catalysing the biotransformation of sulphonylureas. Total oral clearance of all studied sulphonylureas (tolbutamide, glibenclamide [glyburide], glimepiride, glipizide) was only about 20% in persons with the CYP2C9*3/*3 genotype compared with carriers of the wild-type genotype CYP2C9*1/*1, and clearance in the heterozygous carriers was between 50% and 80% of that of the wild-type genotypes. For reasons not completely known, the resulting differences in drug effects were much less pronounced. Nevertheless, CYP2C9 genotype-based dose adjustments may reduce the incidence of adverse effects. The magnitude of how doses might be adjusted can be derived from pharmacokinetic studies. The meglitinide-class drug nateglinide is metabolised by CYP2C9. According to the pharmacokinetic data, moderate dose adjustments based on CYP2C9 genotypes may help in reducing interindividual variability in the antihyperglycaemic effects of nateglinide. Repaglinide is metabolised by CYP2C8 and, according to clinical studies, CYP2C8*3 carriers had higher clearance than carriers of the wild-type genotypes; however, this was not consistent with in vitro data and therefore further studies are needed. CYP2C8*3 is closely linked with CYP2C9*2. CYP2C8 and CYP3A4 are the main enzymes catalysing biotransformation of the thiazolidinediones troglitazone and pioglitazone, whereas rosiglitazone is metabolised by CYP2C9 and CYP2C8. The biguanide metformin is not significantly metabolised but polymorphisms in the organic cation transporter (OCT) 1 and OCT2 may determine its pharmacokinetic variability. In conclusion, pharmacogenetic variability plays an important role in the pharmacokinetics of oral antidiabetic drugs; however, to date, the impact of this variability on clinical outcomes in patients is mostly unknown and prospective studies on the medical benefit of CYP genotyping are required.

The place of sulfonylureas in the therapy for type 2 diabetes mellitus

Sulfonylureas are still largely used for treatment of type 2 diabetic patients, and they still occupy a central position in many international therapy guidelines. More recently concern has been raised with respect to possible adverse effects associated with the use of these agents. Sulfonylureas are, indeed, believed to favor the development of hypoglycemia, to accelerate beta cell apoptosis and beta-cell exhaustion, and to impair endothelial function with increased risk for ischemic complications. However, because of the intrinsic pathogenetic heterogeneity of type 2 diabetes, sulfonylureas are likely to remain a therapeutic option. Careful choice of a specific sulfonylurea should be made on the basis of efficacy, safety, convenience, tissue specificity, and neutrality with respect to the beta cell. In this review the advantage:disadvantage ratio of available sulfonylureas is analyzed with the purpose of providing a critical clinical appraisal of the role of sulfonylureas in the modern treatment of type 2 diabetes.

Glucose concentration-dependent potentiation of insulin secretion by a new chemical entity, KCP256

The insulinotropic activity of KCP256 [(R)-8-benzyl-2-cyclopentyl-7, 8-dihydro-4-propyl-1H-imidazo[2,1-i]purin-5(4H)-one hydrochloride] was examined using MIN6 cells (a pancreatic beta-cell line) and pancreatic islets isolated from rats. Unlike sulfonylurea anti-diabetic drugs, KCP256 dose-dependently (0.1-10 microM) enhanced insulin secretion from MIN6 cells and its insulinotropic effect was exerted only at high concentrations of glucose (8.3-22 mM) but not at low concentrations of glucose (3.3-5.5 mM). Furthermore, the action mechanism of KCP256 was different because, unlike sulfonylurea drugs, KCP256 did not displace the binding of [3H]glibenclamide, and did not inhibit the 86Rb+ efflux nor K(ATP) channel activity. In isolated islets, KCP256 also enhanced insulin secretion in a dose- and a glucose-concentration-dependent manner. Plasma levels of insulin after glucose challenge in KCP256-administrated rats were higher than those in vehicle-administrated animals, indicating that KCP256 can enhance insulin secretion in vivo. Since the insulinotropic activity of KCP256 only occurs at high concentrations of glucose, this novel drug may exhibit a decreased risk of drug-induced hypoglycemia compared with sulfonylurea drugs when treating patients with diabetes.

K579, a slow-binding inhibitor of dipeptidyl peptidase IV, is a long-acting hypoglycemic agent

Dipeptidyl peptidase IV inhibitors are expected to be categorized in a new type of antidiabetic drugs. We had developed a long-acting dipeptidyl peptidase IV inhibitor, K579 [(S)-1-[4-methyl-1-(2-pyrimidinyl)-4-piperidylamino]acetyl-2-pyrrolidinecarbonitrile]. The aim of present study was to characterize the pharmacological profiles of K579. In normal rats, K579 suppressed the blood glucose elevation after an oral glucose tolerance test with the increment of plasma insulin and active forms of glucagon-like peptide-1 (GLP-1). During repetitive glucose loading using Zucker fatty rats, pretreatment with K579 attenuated the glucose excursion after the second glucose loading as well as the first glucose loading without inducing hypoglycemia. The kinetic study using cell extract revealed that K579 was a more potent and slower binding inhibitor than the existing dipeptidyl peptidase IV inhibitor (NVP-DPP728, 1-[[[2-[(5-cyanopyridin-2-yl)amino]ethyl]amino]acetyl]-2-cyano-(S)-pyrrolidine). These profiles of K579 might be advantageous over the existing dipeptidyl peptidase IV inhibitor with respect to less dosing frequency.

Towards Single-Tablet Therapy for Type 2 Diabetes Mellitus

Type 2 diabetes mellitus emerges as a result of multiple pathophysiologic changes. If the pharmacotherapy of type 2 diabetes should be tailored to the underlying pathophysiology, it would be necessary to use a combination of agents with complementary mechanisms of action. The two principal defects in type 2 diabetes are insulin deficiency and insulin resistance. Therefore, combining an insulin-providing agent with an insulin-sensitizing agent will augment the efficacy of current antihyperglycemic agents. This is the rationale for the development and marketing of sulfonylurea/metformin combination tablets.Randomized double-blind clinical trials have shown the safety and efficacy of these fixed combination tablets in both drug-naive individuals as well as in those individuals not achieving glycemic goals on sulfonylurea or metformin monotherapy. These studies have also shown that these tablets may be associated with better postprandial glycemic control compared with monotherapy. However, the risk of hypoglycemia is increased with the use of combination tablets, especially in drug-naive individuals with baseline glycosylated hemoglobins of <8.0%. Combining two insulin-sensitizing agents that have different mechanisms of action and that target different biochemical pathways, would also enhance efficacy. This can be accomplished by combining metformin with rosiglitazone or pioglitazone. The recently developed fixed formulation tablet of metformin/rosiglitazone is available for use as second-line therapy in individuals who have not reached their glycemic goals while on metformin. The advantages of combining several agents in one tablet include convenience and enhanced adherence to therapy. The main disadvantage is the loss of administration flexibility.

Thiazolidinediones in type 2 diabetes mellitus: current clinical evidence

Type 2 diabetes mellitus is characterised by insulin resistance as well as progressive pancreatic beta cell dysfunction. The cornerstone of current oral blood-glucose lowering therapy consists of metformin, which primarily lowers hepatic glucose production, and the sulphonylureas that act by stimulating pancreatic beta-cells to secrete insulin. Recently, a novel class of agents, the thiazolidinediones, has been introduced that favourably influence insulin sensitivity and possibly also pancreatic beta-cell function. The thiazolidinediones are synthetic ligands that bind to the nuclear peroxisome proliferator-activated receptor-gamma and exert their action by activating transcription of genes that, among others, regulate adipocyte differentiation and adipogenesis as well as glucose and lipid metabolism. To date, the precise mechanisms underlying the actions of thiazolidinediones are largely unknown. When given as monotherapy or in combination with sulphonylureas, metformin or insulin in patients with type 2 diabetes, the currently available thiazolidinediones (rosiglitazone and pioglitazone) ameliorate glycaemic control, by lowering fasting and postprandial blood glucose levels, and improve insulin sensitivity in placebo-controlled trials. They seem to have differential effects on dyslipidaemia in patients with type 2 diabetes; rosiglitazone increases total cholesterol as well as high-density lipoprotein (HDL) and low-density lipoprotein cholesterol levels and affects plasma triglyceride levels depending on the baseline values, whereas pioglitazone lowers triglycerides and increases HDL cholesterol levels. The adverse events of both agents that occur with greater frequency than in patients treated with placebo are fluid retention and oedema. As demonstrated, mainly in preclinical studies to date, rosiglitazone and pioglitazone possess beneficial effects on other cardiovascular risk factors associated with the insulin resistance syndrome. Thus, these agents were shown to decrease blood pressure, enhance myocardial function and fibrinolysis, as well as possess anti-inflammatory and other beneficial vascular effects. Long-term efficacy and surveillance of this promising class of drugs in patients, however, still need to be demonstrated in outcome trials.