Comparative tolerability of sulphonylureas in diabetes mellitus

Thiolated Chitosans: Design and In Vivo Evaluation of a Mucoadhesive Buccal Peptide Drug Delivery System

PURPOSE

Intravenous application of pituitary adenylate cyclase-activating polypeptide (PACAP) has been identified as a promising strategy for the treatment of type 2 diabetes. To generate a more applicable formulation, it was the aim of this study to develop a sustained buccal delivery system for this promising therapeutic peptide.

METHODS

2-Iminothiolane was covalently bound to chitosan to improve the mucoadhesive and permeation-enhancing properties of chitosan used as drug carrier matrix. The resulting chitosan-4-thiobutylamidine conjugate was homogenized with the enzyme inhibitor and permeation mediator glutathione (gamma-Glu-Cys-Gly), Brij 35, and PACAP (formulation A). The mixture was lyophilized and compressed into flat-faced discs (18 mm in diameter). One formulation was additionally coated on one side with palm wax (formulation B). Tablets consisting of unmodified chitosan and PACAP (formulation C) or of unmodified chitosan, Brij 35, and PACAP (formulation D) served as controls. Bioavailability studies were performed in pigs by buccal administration of these test formulations. Blood samples were analyzed via an ELISA method.

RESULTS

Formulations A and B led to an absolute bioavailability of 1%, whereas PACAP did not reach the systemic circulation when administered via formulations C and D. Moreover, in the case of formulations A and B, a continuously raised plasma level of the peptide drug being in the therapeutic range could be maintained over the whole period of application (6 h). Formulations A and B were removed by moderate force from the buccal mucosa after 6 h, whereas formulations C and D detached from the mucosa 4 h after application.

CONCLUSION

The study reveals this novel mucoadhesive delivery system to be a promising approach for buccal delivery of PACAP.

Left ventricular diastolic dysfunction in diabetic patients: pathophysiology and therapeutic implications

Patients with signs and symptoms of heart failure and a preserved left ventricular (LV) systolic function may have significant abnormalities in diastolic function. This condition is called diastolic heart failure (DHF) and is observed in about 40% of patients with chronic heart failure (CHF). Diabetes mellitus is one of the major risk factors for DHF. Diastolic dysfunction is observed in about 40% of patients with diabetes mellitus and correlates with poor glycemic control. Suggested mechanisms for diastolic dysfunction in the diabetic heart are: (i) abnormalities in high-energy phosphate metabolism; (ii) impaired calcium transport; (iii) interstitial accumulation of advanced glycosylation end products; (iv) imbalance in collagen synthesis and degradation; (v) abnormal microvascular function, (vi) activated cardiac renin-angiotensin system; (vii) decreased adiponectin levels; and (viii) alteration in the metabolism of free fatty acids and glucose. Because most large, randomized clinical trials in CHF have enrolled only patients with systolic dysfunction, the specific management of diastolic dysfunction is largely unknown. The CHARM-Preserved (Candesartan in Heart Failure: Assessment of Reduction in Mortality and Morbidity-Preserved) trial, the only mega trial specific for DHF (LV ejection fraction >40%), showed that the angiotensin II type 1 receptor antagonist (angiotensin receptor blocker [ARB]) candesartan cilexetil reduced hospital admissions for CHF but not cardiovascular death. Currently, the pharmacologic treatment used in systolic heart failure is also recommended in DHF and includes administration of diuretics and nitrates for pulmonary congestion, and long-term management with ACE inhibitors, ARBs, aldosterone antagonists, and beta-adrenoceptor antagonists. Poor glycemic control is associated with a high incidence of heart failure in diabetic patients, but the preferable antihyperglycemic regimen for DHF in patients with diabetes mellitus needs to be determined in further studies.

Chlorpropamide 2-hydroxylation is catalysed by CYP2C9 and CYP2C19 in vitro: chlorpropamide disposition is influenced by CYP2C9, but not by CYP2C19 genetic polymorphism

AIMS

We evaluated the involvement of cytochrome P450 (CYP) isoforms 2C9 and 2C19 in chlorpropamide 2-hydroxylation in vitro and in chlorpropamide disposition in vivo.

METHODS

To identify CYP isoforms(s) that catalyse 2-hydroxylation of chlorpropamide, the incubation studies were conducted using human liver microsomes and recombinant CYP isoforms. To evaluate whether genetic polymorphisms of CYP2C9 and/or CYP2C19 influence the disposition of chlorpropamide, a single oral dose of 250 mg chlorpropamide was administered to 21 healthy subjects pregenotyped for CYP2C9 and CYP2C19.

RESULTS

In human liver microsomal incubation studies, the formation of 2-hydroxychlorpropamide (2-OH-chlorpropamide), a major chlorpropamide metabolite in human, has been best described by a one-enzyme model with estimated K(m) and V(max) of 121.7 +/- 19.9 microm and 16.1 +/- 5.0 pmol min(-1) mg(-1) protein, respectively. In incubation studies using human recombinant CYP isoforms, however, 2-OH-chlorpropamide was formed by both CYP2C9 and CYP2C19 with similar intrinsic clearances (CYP2C9 vs. CYP2C19: 0.26 vs. 0.22 microl min(-1) nmol(-1) protein). Formation of 2-OH-chlorpropamide in human liver microsomes was significantly inhibited by sulfaphenazole, but not by S-mephenytoin, ketoconazole, quinidine, or furafylline. In in vivo clinical trials, eight subjects with the CYP2C9*1/*3 genotype exhibited significantly lower nonrenal clearance [*1/*3 vs.*1/*1: 1.8 +/- 0.2 vs. 2.4 +/- 0.1 ml h(-1) kg(-1), P < 0.05; 95% confidence interval (CI) on the difference 0.2, 1.0] and higher metabolic ratios (of chlorpropamide/2-OH-chlorpropamide in urine: *1/*3 vs.*1/*1: 1.01 +/- 0.19 vs. 0.56 +/- 0.08, P < 0.05; 95% CI on the difference - 0.9, - 0.1) than did 13 subjects with CYP2C9*1/*1 genotype. In contrast, no differences in chlorpropamide pharmacokinetics were observed for subjects with the CYP2C19 extensive metabolizer vs. poor metabolizer genotypes.

CONCLUSIONS

These results suggest that chlorpropamide disposition is principally determined by CYP2C9 activity in vivo, although both CYP2C9 and CYP2C19 have a catalysing activity of chlorpropamide 2-hydroxylation pathway.

In vitro evaluation of various buccal permeation enhancing systems for PACAP (pituitary adenylate cyclase-activating polypeptide)

PURPOSE

Buccal administration of pituitary adenylate cyclase-activating polypeptide (PACAP) could represent a new possibility for the treatment of type 2 diabetes. In this study the effect of various buccal permeation enhancers on PACAP and FD-4 was evaluated.

METHODS

The permeation-enhancing properties of the well-established permeation enhancers sodium deoxycholate (Na DOC) and cetrimide on the permeation of PACAP were investigated on freshly excised porcine buccal mucosa in Ussing chambers. Furthermore, the effect of chitosan and that of chitosan-4-thiobutylamidine conjugate (chitosan-TBA) optionally in combination with reduced glutathione (GSH) on the permeation of PACAP across the buccal mucosa was studied.

RESULTS

The apparent permeability coefficient (P(app)) of PACAP in buffer only was 5.7 +/- 3.1x10(-8) cm/s. In the presence of 5% (m/v) Na DOC, the enhancement of the permeation was 18.6-fold, whereas due to the addition of 5% (m/v) cetrimide an enhancement ratio of 46.5 was obtained. In the presence of the chitosan-TBA conjugate (1%), a 38.9-fold increased permeation was achieved, whereas unmodified chitosan (1%) did not show any effect. The combination of chitosan-TBA conjugate (1%) with GSH (2%) led to an increase in P(app) up to 441.7 +/- 89.9x10(-8) cm/s, which represents a 77.5-fold improvement. The P(app) of GSH per se was only 1.0 +/- 0.2x10(-9) cm/s, showing that GSH remains concentrated on the surface of the buccal mucosa. Results were confirmed by additional permeation studies performed with FD-4 used as hydrophilic macromolecular test compound.

CONCLUSIONS

Based on their permeation-enhancing properties, chitosan-TBA conjugates represent a promising tool for the buccal administration of peptide drugs, e.g., PACAP.

Trends in the prevalence and management of diagnosed type 2 diabetes 1994-2001 in England and Wales

BACKGROUND

Type 2 diabetes is an important cause of morbidity and mortality. Its prevalence appears to be increasing. Guidelines exist regarding its management. Recommendations regarding drug therapy have changed. Little is known about the influence of these guidelines and changed recommendations on the actual management of patients with type 2 diabetes. This study aims to document trends in the prevalence, drug treatment and recording of measures related to the management of type 2 diabetes; and to assess whether recommended targets can be met.

METHODS

The population comprised subjects registered between 1994 and 2001 with 74 general practices in England and Wales which routinely contribute to the Doctors' Independent Network database. Approximately 500,000 patients and 10,000 type 2 diabetics were registered in each year.

RESULTS

Type 2 diabetes prevalence rose from 17/1000 in 1994 to 25/1000 in 2001. Drug therapy has changed: use of long acting sulphonylureas is falling while that of short acting sulphonylureas, metformin and newer therapies including glitazones is increasing. Electronic recording of HbA1c, blood pressure, cholesterol and weight have risen steadily, and improvements in control of blood pressure and cholesterol levels have occurred. However, glycaemic control has not improved, and obesity has increased. The percentage with a BMI under 25 kg/m2 fell from 27.0% in 1994 to 19.4% in 2001 (p < 0.001).

CONCLUSION

Prevalence of type 2 diabetes is increasing. Its primary care management has changed in accordance with best evidence. Monitoring has improved, but further improvement is possible. Despite this, glycaemic control has not improved, while the prevalence of obesity in the diabetic population is rising.

Polypharmacy and Possible Drug-Drug Interactions Among Diabetic Patients Receiving Home Health Care Services

OBJECTIVES

In this study, we examined the drug regimens of diabetic patients receiving home health care services to measure the prevalence of polypharmacy and to assess the likelihood of drug-drug interactions, a consequence of polypharmacy.

DESIGN

The sample consisted of 139 diabetic patients who received home health care services from one home health agency in a large mid-Atlantic city. The data were collected from March 1, 1998 to September 30, 1999. Information regarding medications was collected by the home health nurse during the initial home visit and was recorded on the medication sheet in the patient's clinical record. Any changes in medications were noted on the medication sheets.

METHODS

We identified all systemic medications prescribed for 139 home health patients. To assess drug-drug interactions, we used Micromedex formulary DRUG-REAX System.

OUTCOMES

We calculated (1) the number of systemic medications taken, and (2) the number of possible severe, moderate, and mild drug-drug interactions.

RESULTS

We found that the average number of medications taken was 8.9 (SD 3.4) prescribed medications per day. Our results show that 38.8% of the patients in the sample could potentially be subject to at least one severe drug-drug interaction. Nearly all of the patients (92.8%) were at risk for moderate drug-drug interactions, and 70.5% could have mild drug- drug interactions.

CONCLUSION

We conclude that polypharmacy is a concern for home health care patients with diabetes and the potential for drug-drug interactions is substantial. Our results indicate that the drug regimens of diabetic patients should be monitored systematically to avoid adverse events such as hospitalization. Family practitioners and home health care takers are in a unique position to identify polypharmacy and to modify drug regimens.

Deadly pediatric poisons: nine common agents that kill at low doses

More than 97% of pediatric exposures reported to the AAPCC in 2001 had either no effect or mild clinical effects. Despite the large number of exposures, only 26 of the 1074 reported fatalities occurred in children younger than age 6. These findings reflect the fact that, in contrast to adolescent or adult ingestions, pediatric ingestions are unintentional events secondary to development of exploration behaviors and the tendency to place objects in the mouth. Ingested substances typically are nontoxic or ingested in such small quantities that toxicity would not be expected. As a result, it commonly is believed that ingestion of one or two tablets by a toddler is a benign act and not expected to produce any consequential toxicity. Select agents have the potential to produce profound toxicity and death, however, despite the ingestion of only one or two tablets or sips. Although proven antidotes are a valuable resource, their value is diminished if risk after ingestion is not adequately appreciated and assessed. Future research into low-dose, high-risk exposures should be directed toward further clarification of risk, improvements in overall management strategies,and, perhaps most importantly, prevention of toxic exposure through parental education and appropriate safety legislation.

The role of sulphonylureas in the management of type 2 diabetes mellitus

The sulphonylureas act by triggering insulin release from the pancreatic beta cell. A specific site on the adenosine triphosphate (ATP)-sensitive potassium channels is occupied by sulphonylureas leading to closure of the potassium channels and subsequent opening of calcium channels. This results in exocytosis of insulin. The meglitinides are not sulphonylureas but also occupy the sulphonylurea receptor unit coupled to the ATP-sensitive potassium channel. Glibenclamide (glyburide), gliclazide, glipizide and glimepiride are the primary sulphonylureas in current clinical use for type 2 diabetes mellitus. Glibenclamide has a higher frequency of hypoglycaemia than the other agents. With long-term use, there is a progressive decrease in the effectiveness of sulphonylureas. This loss of effect is the result of a reduction in insulin-producing capacity by the pancreatic beta cell and is also seen with other antihyperglycaemic agents. The major adverse effect of sulphonylureas is hypoglycaemia. There is a theoretical concern that sulphonylureas may affect cardiac potassium channels resulting in a diminished response to ischaemia. There are now many choices for initial therapy of type 2 diabetes in addition to sulphonylureas. Metformin and thiazolidinediones affect insulin sensitivity by independent mechanisms. Disaccharidase inhibitors reduce rapid carbohydrate absorption. No single agent appears capable of achieving target glucose levels in the majority of patients with type 2 diabetes. Combinations of agents are successful in lowering glycosylated haemoglobin levels more than with a single agent. Sulphonylureas are particularly beneficial when combined with agents such as metformin that decrease insulin resistance. Sulphonylureas can also be given with a basal insulin injection to provide enhanced endogenous insulin secretion after meals. Sulphonylureas will continue to be used both primarily and as part of combined therapy for most patients with type 2 diabetes.

Hospital hypoglycemia: not only treatment but also prevention

OBJECTIVE

To propose a strategy, applicable on general hospital wards, for prevention of hypoglycemia in hospitalized patients.

RESULTS

Although the mortality rate among hospitalized patients with hypoglycemia has been shown to be 22.2 to 27% in series that included patients with diabetes, some investigators have shown that hypoglycemia is not an independent predictor of mortality. Outside the critical care setting, the comparative risks of hyperglycemia and hypoglycemia and the relationship of hospital hypoglycemia to intensification of glycemic control have not been determined. The reported incidence of hospital hypoglycemia ranges from 1.2% for hospitalized adults to 20% for nonpregnant patients with diabetes admitted without a metabolic emergency. Among patients receiving antihyperglycemic therapy, the literature describes precipitating events--usually a sudden change of caloric exposure-- and predisposing conditions for hypoglycemic episodes.

CONCLUSION

Hospital hypoglycemia is predictable, and it is preventable by measures other than undertreatment of hyperglycemia. Physician orders for antihyperglycemic therapy should be written and, if necessary, be revised so as to respond to the presence of predisposing conditions for hypoglycemia. A ward-based protocol or hospital-wide policy should establish the appropriate response to triggering events. Within the time frame of action of previously administered antihyperglycemic drugs (after abrupt interruption of caloric exposure), the threshold for preventive intravenous administration of dextrose is a glucose concentration of 120 mg/dL.

Sulfonylurea treatment of type 2 diabetes mellitus: focus on glimepiride

Sulfonylureas, which have evolved through two generations since their introduction nearly 50 years ago, remain the most frequently prescribed oral agents for treatment of patients with type 2 diabetes mellitus. Glyburide, glipizide, and glimepiride, the newest sulfonylureas, are as effective at lowering plasma glucose concentrations as first-generation agents but are more potent, better tolerated, and associated with a lower risk of adverse effects. Differences in their binding affinity to the beta-cell sulfonylurea receptor have been described, with preservation of cardioprotective responses to ischemia with glimepiride. Clinical studies have shown glimepiride to be safe and effective in reducing fasting and postprandial glucose levels, as well as glycosylated hemoglobin concentrations, with dosages of 1-8 mg/day. In comparative trials, glimepiride was as effective in lowering glucose levels as glyburide and glipizide, but glimepiride was associated with a reduced likelihood of hypoglycemia and a smaller increase in fasting insulin and C-peptide levels than glyburide, and a more rapid lowering of fasting plasma glucose levels than glipizide. Glimepiride also improves first-phase insulin secretion, which plays an important role in reducing postprandial hyperglycemia. Insulin secretagogues, specifically glimepiride, merit consideration as first-line therapy for patients with type 2 diabetes.

The Effect of Deinsuring Chlorpropamide on the Prescribing of Oral Antihyperglycemics for Nova Scotia Seniors’ Pharmacare Beneficiaries

On behalf of the Nova Scotia Seniors' Pharmacare Program, the Drug Evaluation Alliance of Nova Scotia developed a multicomponent intervention plan to facilitate the removal of chlorpropamide as an insured benefit. Chlorpropamide has caused serious hypoglycemia in seniors to a greater extent than some other agents. Pharmacy administrative claims were used to compute monthly use rates for insulin and each oral antihyperglycemic drug from January 1, 2000-December 30, 2002, in an intervention cohort (patients receiving chlorpropamide) and a control cohort (patients receiving an antihyperglycemic agent other than chlorpropamide). Initially, 630 patients were receiving chlorpropamide therapy. By the time chlorpropamide was deinsured, only 10% of the treatment cohort continued receiving chlorpropamide; shortly after deinsurance, no beneficiaries continued receiving the drug. The antihyperglycemics with the greatest increase in prescription were glyburide and gliclazide. The deinsuring of chlorpropamide and the educational strategies that accompanied it resulted in the selection of more appropriate antihyperglycemics for Nova Scotia seniors.

Culture-specific diabetes care for Surinam South Asians with a low socio-economic position: who benefits?

The South Asians in The Netherlands have a high diabetes prevalence in combination with a low socio-economic position. A new, culture-specific type of care was developed. This intervention study investigates which patient characteristics are associated with success and whether those in the lowest socio-economic position have been reached. Before and after the end of the intensive guidance, the HbAlc of the patients (n=101) was measured. The following variables were significantly related to success (defined as a decrease in HbAlc > or = 0.8%): a high initial HbAlc, a low BMI and presence of complications. The average improvement in HbAlc was significant only in the group with a higher socio-economic position. Although the patients with the lowest socio-economic position did not sufficiently benefit from this intervention, an overall improvement was achieved in this poorly educated study population. The further improvements in the care after the completion of this study should be evaluated.

Comparison of glycaemic control and cardiovascular risk profile in patients with type 2 diabetes during treatment with either repaglinide or metformin

OBJECTIVE

To compare glycaemic control and cardiovascular risk profile in patients with type 2 diabetes following 12 months' treatment with either repaglinide or metformin.

STUDY DESIGN AND METHODS

This was an open uncontrolled randomised study in n=112 patients with inadequately controlled type 2 diabetes not previously treated with oral hypoglycaemic agents. Patients beginning treatment with either repaglinide or metformin entered an 8-week titration period (to optimise dosage: repaglinide, 2-4 mg/day; metformin, 1500-2500 mg/day) followed by a 12-month treatment period. Glycaemic control and cardiovascular risk factors were determined at baseline and at the end of the treatment period.

RESULTS

Mean (S.D.) final drug doses were 3 (+/-1) mg/day in the repaglinide group and 2000 (+/-500) mg/day in the metformin group. Significant improvements in glycaemic control [glycated haemoglobin, fasting and 2-h postprandial plasma glucose (PPG)] were demonstrated in both treatment groups. The decrease in PPG was significantly greater in the repaglinide group (P<0.05). During the treatment period, fasting plasma insulin (FPI) decreased significantly in both groups, more so with metformin (P<0.05). Two-hour postprandial plasma insulin (PPI) levels decreased only in the metformin group (P<0.05). Significant improvements between baseline and final visit were demonstrated in one or both groups in the following cardiovascular risk factors: total cholesterol, low-density lipoprotein cholesterol (LDL-C), triglycerides, plasminogen activator inhibitor, lipoprotein(a) and homocysteine. No changes were observed in high-density lipoprotein cholesterol (HDL-C), apolipoprotein A-I, apolipoprotein B, fibrinogen, body mass index (BMI) or blood pressure.

CONCLUSIONS

The use of repaglinide or metformin in drug therapy-nai;ve patients with type 2 diabetes over a 12-month period is associated with improvements in both glycaemic control and cardiovascular risk profile. The latter cannot necessarily be attributed to the pharmacotherapy per se, but provides reassurance in the context of initiating oral hypoglycaemic drug therapy with these agents.

Imidazoline NNC77-0074 stimulates insulin secretion and inhibits glucagon release by control of Ca(2+)-dependent exocytosis in pancreatic alpha- and beta-cells

We have investigated the effects of the novel imidazoline compound (+)-2-(2-(4,5-dihydro-1H-imidazol-2-yl)-thiopene-2-yl-ethyl)-pyridine (NNC77-0074) on stimulus-secretion coupling in isolated pancreatic alpha- and beta-cells. NNC77-0074 stimulated glucose-dependent insulin secretion in intact mouse pancreatic islets. No effect was observed at </=2.5 mM glucose and maximal stimulation occurred at 10-15 mM glucose. NNC77-0074 produced a concentration-dependent stimulation of insulin secretion. Half-maximal (EC(50)) stimulation was observed at 24 microM and at maximally stimulatory concentrations insulin release was doubled. The stimulatory action of NNC77-0074 on insulin secretion was not associated with membrane depolarisation or a change in the activity of ATP-sensitive K(+) channels. Using capacitance measurements, we found that NNC77-0074 stimulated depolarisation-induced exocytosis 2.6-fold without affecting the whole-cell Ca(2+) current when applied via the extracellular medium. The concentration dependence of the stimulatory action was determined by intracellular application of NNC77-0074 through the recording pipette. NNC77-0074 stimulated exocytosis half-maximal at 44 nM and at maximally stimulatory concentrations the rate of exocytosis was increased twofold. NNC77-0074 stimulated depolarised-induced insulin secretion from islets exposed to diazoxide and high external KCl (EC(50)=0.45 microM). The stimulatory action of NNC77-0074 was dependent on protein kinase C activity. NNC77-0074 potently inhibited glucagon secretion from rat islets (EC(50)=11 nM). This was not associated with a change in spontaneous electrical activity and ATP-sensitive K(+) channel activity but resulted from a reduction of the rate of Ca(2+)-dependent exocytosis in single rat alpha-cells (EC(50)=9 nM). Inhibition of exocytosis by NNC77-0074 was pertussis toxin-sensitive and mediated by activation of the protein phosphatase calcineurin. In rat somatotrophs, PC12 cells and mouse cortical neurons NNC77-0074 did not stimulate Ca(2+)-evoked exocytosis, whereas the other imidazoline compounds phentolamine and efaroxan produced 2.5-fold stimulation of exocytosis. Our data suggest that the imidazoline compound NNC77-0074 constitutes a novel class of antidiabetic compounds that stimulates glucose-dependent insulin release while inhibiting glucagon secretion. These actions are exclusively exerted by modulation of exocytosis of the insulin- and glucagon-containing granules.

Nateglinide improves glycaemic control when added to metformin monotherapy: results of a randomized trial with type 2 diabetes patients

AIMS/HYPOTHESIS

This study evaluated the addition of nateglinide, a d-phenylalanine derivative that restores early phase insulin release, to metformin in type 2 diabetes patients stabilized on high-dose metformin.

METHODS

This multicentre, double-blind, parallel group trial included 467 metformin-treated patients with glycosylated haemoglobin (HbA1c) between 6.8% and 11%. Patients were randomized to add nateglinide 60 mg, 120 mg or placebo before three meals to metformin 1000 mg b.i.d. for 24 weeks.

RESULTS

HbA1c was significantly reduced with nateglinide 60 mg and 120 mg plus metformin compared with metformin control (-0.36%, p = 0.003; -0.59%, p < 0.001 respectively). Greater benefits occurred if patients had elevated HbA1c at baseline (-1.38% with nateglinide 120 mg in patients with HbA1c > 9.5%). A modest fasting plasma glucose reduction was observed. Most symptoms suggestive of hypoglycaemia occurred in patients with low HbA1c levels (<or= 8%) at baseline, although no confirmed cases of hypoglycaemia occurred with nateglinide 60 mg in this patient group. Events suggestive of hypoglycaemia were confirmed in 1.1% of cases (plasma glucose <or= 3.3 mmol/l). Weight gain over 24 weeks was 0.9 kg with nateglinide 120 mg vs. metformin alone, and plasma lipids remained unchanged.

CONCLUSIONS/INTERPRETATION

In patients stabilized on high-dose metformin, the addition of nateglinide improved glycaemic control. The combination of these agents was well tolerated and both doses of nateglinide proved effective. The efficacy of nateglinide 60 mg and the low rate of hypoglycaemia observed at this dose make it suitable for patients close to their therapeutic target on metformin monotherapy.

Oral agents for the treatment of type 2 diabetes mellitus: pharmacology, toxicity, and treatment

Currently available oral agents for the treatment of type 2 diabetes mellitus include a variety of compounds from 5 different pharmacologic classes with differing mechanisms of action, adverse effect profiles, and toxicities. The oral antidiabetic drugs can be classified as either hypoglycemic agents (sulfonylureas and benzoic acid derivatives) or antihyperglycemic agents (biguanides, alpha-glucosidase inhibitors, and thiazolidinediones). In this review, a brief discussion of the pharmacology of these agents is followed by an examination of the adverse effects, drug-drug interactions, and toxicities. Finally, treatment of sulfonylurea-induced hypoglycemia is described, including general supportive care and the management of pediatric sulfonylurea ingestions. The adjunctive roles of glucagon, diazoxide, and octreotide for refractory hypoglycemia are also discussed.

Non insulin-dependent diabetes mellitus (type 2) secondary failure. Metformin-glibenclamide treatment

The goal of sulphonylurea (S) treatment in Non-Insulin-Dependent Diabetes Mellitus (NIDDM - type 2 diabetes) subjects should be to obtain a satisfactory glycemic control (fasting glycemic levels &#x003C; 140 mg&#x0025;). The loss of an adequate blood glucose control after an initial variable period of S is known as secondary failure (SF). The number of SF are extremely variable among different trials for many reasons, some of which are patient-related: increased food intake, weight gain, non-compliance, poor physical activity, stress, diseases and&#x00F7;or impaired pancreatic beta cell function, desensitization after S chronic therapy, reduced absorption, concomitant therapies. Many therapeutic strategies have been proposed to achieve an adequate metabolic control in type 2 diabetes patients: switch to intensive insulin therapy and subsequent return to S therapy; association with insulin; association with sulphonylureas plus biguanides. The association biguanides and S, in particular glibenclamide plus metformin, is now widely used by diabetologists in SF since glibenclamide improves insulin secretion while metformin exerts its antidiabetic.