Comparison of diabetic control in type 2 (non-insulin dependent) diabetic patients treated with different sulphonylureas

Current Position of Gliclazide and Sulfonylureas in the Contemporary Treatment Paradigm for Type 2 Diabetes: A Scoping Review

The increasing burden of type 2 diabetes (T2D), in relation to alarming rise in the prevalence; challenges in the diagnosis, prevention, and treatment; as well as the substantial impact of disease on longevity and quality of life, is a major concern in healthcare worldwide. Sulfonylureas (SUs) have been a cornerstone of T2D pharmacotherapy for over 60 years as oral antidiabetic drugs (OADs), while the newer generation SUs, such as gliclazide modified release (MR), are known to be associated with low risk of hypoglycemia in addition to the cardiovascular neutrality. This scoping review aimed to specifically address the current position of gliclazide MR among other SUs in the contemporary treatment paradigm for T2D and to provide a practical guidance document to assist clinicians in using gliclazide MR in real-life clinical practice. The main topics addressed in this paper include the role of early and sustained glycemic control and use of SUs in T2D management, the properties of gliclazide MR in relation to its effectiveness and safety, the use of gliclazide therapy in special populations, and the place of SUs as a class and gliclazide MR specifically in the current T2D treatment algorithm.

Real-world evidence on the effectiveness and safety of gliclazide MR 60 mg in Bangladeshi patients with Type II diabetes during fasting: a sub-analysis from the global DIA-RAMADAN study

Aim: Many Muslims with Type II diabetes (T2DM) fast during Ramadan, which can put them at increased risk of hypoglycemia. This sub-analysis of the global DIA-RAMADAN study assessed the effectiveness and safety of gliclazide modified release (MR) 60 mg in the Bangladeshi cohort. Materials & methods: DIA-RAMADAN was an international, prospective, observational study conducted in adult T2DM patients intending to fast and receiving gliclazide MR 60 mg once daily for ≥90 days before Ramadan. Dosing was switched from morning to evening at the start of Ramadan. The primary outcome was the proportion of patients with ≥1 symptomatic hypoglycemic event. Secondary outcomes included changes between inclusion (V0) and end of study visit (V1) in glycated hemoglobin (HbA1c), body weight and fasting plasma glucose (FPG). Results: Among the 98 Bangladeshi patients, 80 (81.6%) were at moderate/low-risk (category 3) for fasting and 18 (18.4%) were high-risk (category 2), as per International Diabetes Federation and Diabetes and Ramadan International Alliance (IDF-DAR) guidelines. Gliclazide MR was being prescribed as monotherapy to 59 (60.2%) patients and in combination with metformin to 39 (39.8%). There was no incidence of severe hypoglycemic events. Mean (±SD) HbA1c change from V0 was -0.1 ± 0.8% (p = 0.159). Mean (±SD) changes in FPG and body weight were -0.8 ± 39.7 mg/dl (p = 0.876) and -0.0 ± 1.5 kg (p = 0.810), respectively. Conclusion: In a real-world setting, this sub-analysis in Bangladeshi patients shows that patients with T2DM treated with gliclazide MR 60 mg can fast safely during Ramadan with a very low risk of hypoglycemia, while maintaining glycemic control and body weight.

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.

WITHDRAWN: Sulphonylurea monotherapy for patients with type 2 diabetes mellitus

The Cochrane Metabolic and Endocrine Disorders Group withdrew this review as of Issue 7, 2015 because of the involvement of one author (SS Lund) being employed in a pharmaceutical company. The authors of the review and the Cochrane Metabolic and Endocrine Disorders Group did not find that this was a breach of the rules of the Cochrane Collaboration at the time when it was published. However, after the publication of the review, the Cochrane Collaboration requested withdrawal of the review due to the employment of the author. A new protocol for a review to cover this topic will be published. This will have a new title and a markedly improved protocol fulfilling new and important developments and standards within the Cochrane Collaboration as well as an improved inclusion and search strategy making it necessary to embark on a completely new review project.

The editorial group responsible for this previously published document have withdrawn it from publication.

Safety and efficacy of gliclazide as treatment for type 2 diabetes: a systematic review and meta-analysis of randomized trials

Objective and Design

Gliclazide has been associated with a low risk of hypoglycemic episodes and beneficial long-term cardiovascular safety in observational cohorts. The aim of this study was to assess in a systematic review and meta-analysis of randomized controlled trials the safety and efficacy of gliclazide compared to other oral glucose-lowering agents (PROSPERO2013:CRD42013004156)

Data Sources

Medline, EMBASE, Clinicaltrials.gov, Trialregister.nl, Clinicaltrialsregister.eu and the Cochrane database.

Selection

Included were randomized studies of at least 12 weeks duration with the following outcomes: HbA1c change, incidence of severe hypoglycemia, weight change, cardiovascular events and/or mortality when comparing gliclazide with other oral blood glucose lowering drugs. Bias was assessed with the Cochrane risk of bias tool. The inverse variance random effects model was used.

Results

Nineteen trials were included; 3,083 patients treated with gliclazide and 3,155 patients treated with other oral blood glucose lowering drugs. There was a considerable amount of heterogeneity between and bias in studies. Compared to other glucose lowering agents except metformin, gliclazide was slightly more effective (−0.13% (95%CI: −0.25, −0.02, I² 55%)). One out of 2,387 gliclazide users experienced a severe hypoglycemic event, whilst also using insulin. There were 25 confirmed non-severe hypoglycemic events (2.2%) in 1,152 gliclazide users and 22 events (1.8%) in 1,163 patients in the comparator group (risk ratio 1.09 (95% CI: 0.20, 5.78, I² 77%)). Few studies reported differences in weight and none were designed to evaluate cardiovascular outcomes.

Conclusions

The methodological quality of randomized trials comparing gliclazide to other oral glucose lowering agents was poor and effect estimates on weight were limited by publication bias. The number of severe hypoglycemic episodes was extremely low, and gliclazide appears at least equally effective compared to other glucose lowering agents. None of the trials were designed for evaluating cardiovascular outcomes, which warrants attention in future randomized trials.

Sulphonylurea monotherapy for patients with type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a growing health problem worldwide. Whether sulphonylureas show better, equal or worse therapeutic effects in comparison with other antidiabetic interventions for patients with T2DM remains controversial.

OBJECTIVES

To assess the effects of sulphonylurea monotherapy versus placebo, no intervention or other antidiabetic interventions for patients with T2DM.

SEARCH METHODS

We searched publications in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, LILACS and CINAHL (all until August 2011) to obtain trials fulfilling the inclusion criteria for our review.

SELECTION CRITERIA

We included clinical trials that randomised patients 18 years old or more with T2DM to sulphonylurea monotherapy with a duration of 24 weeks or more.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the risk of bias. The primary outcomes were all-cause and cardiovascular mortality. Secondary outcomes were other patient-important outcomes and metabolic variables. Where possible, we used risk ratios (RR) with 95% confidence intervals (95% CI) to analyse the treatment effect of dichotomous outcomes. We used mean differences with 95% CI to analyse the treatment effect of continuous outcomes. We evaluated the risk of bias. We conducted trial sequential analyses to assess whether firm evidence could be established for a 10% relative risk reduction (RRR) between intervention groups.

MAIN RESULTS

We included 72 randomised controlled trials (RCTs) with 22,589 participants; 9707 participants randomised to sulphonylureas versus 12,805 participants randomised to control interventions. The duration of the interventions varied from 24 weeks to 10.7 years. We judged none of the included trials as low risk of bias for all bias domains. Patient-important outcomes were seldom reported.First-generation sulphonylureas (FGS) versus placebo or insulin did not show statistical significance for all-cause mortality (versus placebo: RR 1.46, 95% CI 0.87 to 2.45; P = 0.15; 2 trials; 553 participants; high risk of bias (HRB); versus insulin: RR 1.18, 95% CI 0.88 to 1.59; P = 0.26; 2 trials; 1944 participants; HRB). FGS versus placebo showed statistical significance for cardiovascular mortality in favour of placebo (RR 2.63, 95% CI 1.32 to 5.22; P = 0.006; 2 trials; 553 participants; HRB). FGS versus insulin did not show statistical significance for cardiovascular mortality (RR 1.36, 95% CI 0.68 to 2.71; P = 0.39; 2 trials; 1944 participants; HRB). FGS versus alpha-glucosidase inhibitors showed statistical significance in favour of FGS for adverse events (RR 0.63, 95% CI 0.52 to 0.76; P = 0.01; 2 trials; 246 participants; HRB) and for drop-outs due to adverse events (RR 0.28, 95% CI 0.12 to 0.67; P = 0.004; 2 trials; 246 participants; HRB).Second-generation sulphonylureas (SGS) versus metformin (RR 0.98, 95% CI 0.61 to 1.58; P = 0.68; 6 trials; 3528 participants; HRB), thiazolidinediones (RR 0.92, 95% CI 0.60 to 1.41; P = 0.70; 7 trials; 4955 participants; HRB), insulin (RR 0.96, 95% CI 0.79 to 1.18; P = 0.72; 4 trials; 1642 participants; HRB), meglitinides (RR 1.44, 95% CI 0.47 to 4.42; P = 0.52; 7 trials; 2038 participants; HRB), or incretin-based interventions (RR 1.39, 95% CI 0.52 to 3.68; P = 0.51; 2 trials; 1503 participants; HRB) showed no statistically significant effects regarding all-cause mortality in a random-effects model. SGS versus metformin (RR 1.47; 95% CI 0.54 to 4.01; P = 0.45; 6 trials; 3528 participants; HRB), thiazolidinediones (RR 1.30, 95% CI 0.55 to 3.07; P = 0.55; 7 trials; 4955 participants; HRB), insulin (RR 0.96, 95% CI 0.73 to 1.28; P = 0.80; 4 trials; 1642 participants; HRB) or meglitinide (RR 0.97, 95% CI 0.27 to 3.53; P = 0.97; 7 trials, 2038 participants, HRB) showed no statistically significant effects regarding cardiovascular mortality. Mortality data for the SGS versus placebo were sparse. SGS versus thiazolidinediones and meglitinides did not show statistically significant differences for a composite of non-fatal macrovascular outcomes. SGS versus metformin showed statistical significance in favour of SGS for a composite of non-fatal macrovascular outcomes (RR 0.67, 95% CI 0.48 to 0.93; P = 0.02; 3018 participants; 3 trials; HRB). The definition of non-fatal macrovascular outcomes varied among the trials. SGS versus metformin, thiazolidinediones and meglitinides showed no statistical significance for non-fatal myocardial infarction. No meta-analyses could be performed for microvascular outcomes. SGS versus placebo, metformin, thiazolidinediones, alpha-glucosidase inhibitors or meglitinides showed no statistical significance for adverse events. SGS versus alpha-glucosidase inhibitors showed statistical significance in favour of SGS for drop-outs due to adverse events (RR 0.48, 95% CI 0.24 to 0.96; P = 0.04; 9 trials; 870 participants; HRB). SGS versus meglitinides showed no statistical significance for the risk of severe hypoglycaemia. SGS versus metformin and thiazolidinediones showed statistical significance in favour of metformin (RR 5.64, 95% CI 1.22 to 26.00; P = 0.03; 4 trials; 3637 participants; HRB) and thiazolidinediones (RR 6.11, 95% CI 1.57 to 23.79; P = 0.009; 6 trials; 5660 participants; HRB) for severe hypoglycaemia.Third-generation sulphonylureas (TGS) could not be included in any meta-analysis of all-cause mortality, cardiovascular mortality or non-fatal macro- or microvascular outcomes. TGS versus thiazolidinediones showed statistical significance regarding adverse events in favour of TGS (RR 0.88, 95% CI 0.78 to 0.99; P = 0.03; 3 trials; 510 participants; HRB). TGS versus thiazolidinediones did not show any statistical significance for drop-outs due to adverse events. TGS versus other comparators could not be performed due to lack of data.For the comparison of SGS versus FGS no meta-analyses of all-cause mortality, cardiovascular mortality, non-fatal macro- or microvascular outcomes, or adverse events could be performed.Health-related quality of life and costs of intervention could not be meta-analysed due to lack of data.In trial sequential analysis, none of the analyses of mortality outcomes, vascular outcomes or severe hypoglycaemia met the criteria for firm evidence of a RRR of 10% between interventions.

AUTHORS' CONCLUSIONS

There is insufficient evidence from RCTs to support the decision as to whether to initiate sulphonylurea monotherapy. Data on patient-important outcomes are lacking. Therefore, large-scale and long-term randomised clinical trials with low risk of bias, focusing on patient-important outcomes are required.

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.

Gliquidone Contributes to Improvement of Type 2 Diabetes Mellitus Management

Diabetes mellitus is a global health problem of steadily increasing proportions, with approximately 95% of patients being affected by the type 2 form of the disease. The growing challenge to healthcare systems presented by this disorder has prompted ongoing research into novel therapies with which to improve management. The sulfonylureas constitute a long-established group of drugs with a proven track record in the treatment of type 2 diabetes, but efforts to improve the overall metabolic profile and safety of these agents have led over time to the addition of newer agents such as the second-generation benzenesulfonylurea gliquidone. Gliquidone has extrapancreatic effects that result in increased numbers of insulin receptors in peripheral tissues. The drug is rapidly and almost completely absorbed after oral administration, and has a short elimination half-life (around 1.5 hours). Metabolism is maintained in patients with hepatic insufficiency, and accumulation does not take place in patients with impaired renal function. Plasma glucose levels are controlled for several hours as a result of glucose-induced insulin secretion, and beneficial effects on plasma lipids have been described. In clinical studies, gliquidone has been associated with less hypoglycaemia than glibenclamide (glyburide), and with metabolic control at least as good as that seen with a number of other sulfonylureas. Beneficial effects on platelet aggregation have been documented, and the drug is described by WHO as the preferred sulfonylurea for patients with mild to moderate renal insufficiency. Importantly, in the light of the well documented consequences of increased bodyweight and the large growth in obesity worldwide, gliquidone is not associated with significant bodyweight gain. Thus, gliquidone is a sulfonylurea with proven efficacy and good safety and metabolic profiles that is only rarely associated with hypoglycaemia. In particular, the metabolism and route of excretion of the drug allow its use in patients who have or may be at risk of diabetic nephropathy.

Gliclazide modified release: from once-daily administration to 24-hour blood glucose control

Although sulfonylureas have been used for more than 40 years, it is only recently that their molecular mechanisms of action have been elucidated. Gliclazide modified release, whose introduction comes soon after the sequencing and cloning of the sulfonylurea receptor, is the first sulfonylurea for which it is possible to detail its action from the moment of oral administration through to its effects on long-term glycemic control. Piecing together these steps for this new agent underlines the rationality of its development and the important differences from other members of the sulfonylurea class. Employing an innovative pharmaceutical form based on a hydrophilic matrix to deliver this short-acting sulfonylurea, gliclazide modified release is associated with an unsurpassed efficacy:acceptability ratio, with the potential additional advantages inherent in reduced dosage and once-daily administration.

The use of sulphonylureas in the elderly

Type 2 diabetes mellitus is a heterogeneous disorder characterised by defects in insulin secretion as well as reduced insulin action. During aging, glucose intolerance will gradually develop, and this is manifested primarily by an increase in the postprandial blood glucose response while fasting blood glucose levels are often less elevated. Abnormal beta-cell secretion of insulin is a main feature of this. Treatment of elderly patients with type 2 diabetes mellitus focuses on reduction of (hyperglycaemic) complaints and prevention of the development or progression of secondary complications. Although regular physical activity and dietary measures, aiming at bodyweight normalisation, are the cornerstones of therapy, pharmacological treatment with oral blood glucose lowering-agents often proves necessary to control the hyperglycaemia. In the United Kingdom Prospective Diabetes Study (UKPDS) it was clearly shown that patients with type 2 diabetes mellitus who were intensively treated with oral blood glucose-lowering agents or insulin developed less microvascular complications. The question whether achievement of strict metabolic control is also of benefit in elderly patients, is still unanswered. Sulphonylureas are drugs which stimulate insulin secretion by enhancing the release of insulin from the pancreatic beta-cells without an effect on insulin synthesis. They are frequently used in the treatment of type 2 diabetes mellitus, and several preparations are available. In general, there are no major differences in effectiveness between the various sulphonylureas. Long term treatment with sulphonylureas will decrease fasting and postprandial plasma glucose levels by 3 to 5 mmol/L, and glycosylated haemoglobin by 20%. However, after its initial decline, plasma glucose level will often go up slightly during the following months to years. Sulphonylureas are usually well tolerated. Hypoglycaemia is the most frequently occurring adverse effect, which may be very serious and damaging in the elderly. It has been associated primarily with long-acting sulphonylureas, like chlorpropamide and glibenclamide (glyburide). Hypoglycaemic episodes may trigger serious events like myocardial infarction or stroke. Therefore, shorter-acting compounds like tolbutamide and gliclazide have been relatively well tolerated and appear to be the best choice to treat elderly patients. It is advisable to start with a low dose and increase the dose, when needed, in small steps. The efficacy of sulphonylureas is much greater when they are taken before a meal. Because of the fact that type 2 diabetes mellitus is a progressive disease, and residual beta-cell function decreases with time, insulin therapy may ultimately be warranted in a significant number of patients.

Comparison of acarbose and metformin in patients with Type 2 diabetes mellitus insufficiently controlled with diet and sulphonylureas: a randomized, placebo-controlled study

AIMS

To compare the efficacy and safety of acarbose and metformin when added to sulphonylurea therapy in diabetic patients insufficiently controlled with sulphonylureas alone.

METHODS

A 12-week, single-centre, placebo-controlled study, with 89 patients randomized to receive acarbose (100 mg t.d.s.), metformin (850 mg b.d.) or placebo in addition to their sulphonylurea therapy. The study was double-blinded with respect to acarbose/placebo and single-blinded for metformin/ acarbose and metformin/placebo. Patients started a strict dietary regimen 1 week before receiving their first dose of acarbose, metformin or placebo. This regimen was individually adjusted to metabolic status and energy requirements.

RESULTS

The primary endpoint, HbA1c, decreased from baseline in all three groups after 12 weeks. The decrease was greater in the two groups receiving active therapy compared with placebo (acarbose -2.3+/-0.32%; metformin -2.5+/-0.16%; placebo -1.3+/-0.34%). There was no significant difference between acarbose and metformin (P=0.65). Differences between both active therapies and placebo were statistically significant (acarbose P < or = 0.01; metformin P < or = 0.004). Reductions in body weight over the treatment period were seen in all three groups and were greatest in the acarbose group (median weight reduction: acarbose 3.5 kg; metformin, 1.0 kg; placebo 1.4 kg). There were no significant differences in the incidence of gastrointestinal side-effects between the three groups and all regimens were generally well tolerated.

CONCLUSION

The results of the study demonstrate the equivalence of acarbose and metformin for improving metabolic control in patients insufficiently controlled with diet and sulphonylureas.

Individual sulfonylureas and serious hypoglycemia in older people

OBJECTIVE

To compare the risk of serious hypoglycemia associated with the use of individual sulfonylureas in older people.

DESIGN

A retrospective cohort study.

SETTING

The Tennessee Medicaid Program.

PATIENTS

A total of 13,963 Medicaid enrollees, aged 65 years or older, who were prescribed one of six sulfonylureas from 1985 to 1989.

MAIN OUTCOME MEASURE

Hospitalization, emergency room admission, or death associated with neuroglycopenic or autonomic symptoms, myocardial infarction, stroke, or injury, with a concomitant blood glucose determination of less than 2.8 mmol/L (50 mg/dL).

RESULTS

We identified 255 persons with a first episode of serious hypoglycemia during 20,715 person-years of sulfonylurea use. The crude rate (per 1000 person-years) of serious hypoglycemia was highest in glyburide users, 16.6 (95% confidence interval [CI], 13.2 to 19.9 and lowest among users of tolbutamide, 3.5 (95% CI, 1.2 to 5.9). Users of tolbutamide, tolazamide, and glipizide had lower risks of serious hypoglycemia than users of chlorpropamide, whereas the risk of serious hypoglycemia among glyburide users did not differ from that of chlorpropamide users. Among second generation sulfonylureas, the adjusted relative risk of severe hypoglycemia among glyburide users, compared with glipizide users, was 1.9 (95% CI, 1.2 to 2.9). An increased risk of serious hypoglycemia associated with use of glyburide compared with glipizide occurred in all strata, including those defined by gender, race, nursing home residence, dose, and duration of use.

CONCLUSIONS

Significant differences in risk of serious hypoglycemia were observed among users of individual agents. This may be explained by duration, timing, or potency of hypoglycemic action. These data confirm previous findings that chlorpropamide use is associated with high risk of hypoglycemia and indicate that among second generation sulfonylureas, glipizide is less associated with hypoglycemia than is glyburide. More information comparing the effectiveness of glycemic control among individual sulfonylureas is needed to assist prescribers in selecting a specific agent for use in clinical practice.

Comparison of efficacy, secondary failure rate, and complications of sulfonylureas

The data from three clinical trials are presented, comparing the efficacy of different sulfonylureas in the treatment of type II diabetes. In a multicenter study, gliclazide improved control in 49% of patients who had failed on other drugs. When five groups of type II diabetic patients were treated concurrently with five randomly allocated different sulfonylureas over 1 year, the percentage of patients achieving normal HbA1 levels was best with gliclazide (80%) and glibenclamide (74%), when compared with chlorpropamide (17%), glipizide (40%), and gliquidone (40%). Secondary failure rate over 5 years was assessed in 248 type II diabetic patients randomly allocated to three different sulfonylureas and found to be lowest with gliclazide (7%) compared with glibenclamide (17.9%): p < 0.1) and glipizide (25.6%: p < 0.005). The incidence of hypoglycemia was significantly higher with glibenclamide than with gliclazide (p < 0.05). The differences in efficacy and secondary failure rate between sulfonylureas may be related to the mechanism of insulin release from the beta-cell and the more physiological action of gliclazide could partly explain this. These trials suggest that gliclazide is a potent sulfonylurea with a low rate of secondary failure and a low incidence of side effects and may be a better choice in long-term sulfonylurea therapy.

Gliclazide. An update of its pharmacological properties and therapeutic efficacy in non-insulin-dependent diabetes mellitus

Gliclazide is a second generation sulphonylurea oral hypoglycaemic agent used in the treatment of non-insulin-dependent diabetes mellitus (NIDDM). It improves defective insulin secretion and may reverse insulin resistance observed in patients with NIDDM. These actions are reflected in a reduction in blood glucose levels which is maintained during both short and long term administration, and is comparable with that achieved by other sulphonylurea agents. Gradually accumulating evidence suggests that gliclazide may be useful in patients with diabetic retinopathy, due to its haemobiological actions, and that addition of gliclazide to insulin therapy enables insulin dosage to be reduced. Thus, gliclazide is an effective agent for the treatment of the metabolic defects associated with NIDDM and may have the added advantage of potentially slowing the progression of diabetic retinopathy. These actions, together with its good general tolerability and low incidence of hypoglycaemia have allowed gliclazide to be well placed within the array of oral hypoglycaemic agents available for the control of NIDDM.

The mode of action and clinical pharmacology of gliclazide: a review

Gliclazide is a sulphonylurea drug with an intermediate half-life of around 11 hours. It is extensively metabolised, and renal clearance accounts for only 4% of total drug clearance. The molecule contains an azabicyclo-octyl group which confers special properties on the basic sulphonylurea moiety. Gliclazide stimulates insulin secretion through the beta cell sulphonylurea receptor, and possibly through a direct effect on intracellular calcium transport. It specifically improves the abnormal first phase insulin release in type 2 diabetes, and also has an effect on the second phase. This pattern of insulin release is thought to explain the lower incidence of hypoglycaemic episodes and weight gain compared with some other sulphonylureas. There is also a reduction in hepatic glucose production and improvement in glucose clearance, without changes in insulin receptors. This suggests a possible post-receptor effect on insulin action, perhaps by stimulation of hepatic fructose-2,6-bisphosphatase and muscle glycogen synthase. Gliclazide reduces platelet adhesion, aggregation and hyperactivity and increases fibrinolysis. These actions, thought to be independent of its hypoglycaemic activity, may make gliclazide useful in halting the progression of diabetic microangiopathy.

Efficacy of gliclazide in comparison with other sulphonylureas in the treatment of NIDDM

Three studies were performed to assess the efficacy of various sulphonylureas in the management of diet-failed NIDDM patients. In the first study, 224 patients inadequately controlled by diet alone or with oral hypoglycaemics received gliclazide in addition to diet or in place of existing drugs for three months. The dosage was adjusted to obtain adequate control or up to the maximum recommended dosage. Good glycaemic control was achieved in 65% of patients. Conversion from other oral hypoglycaemics to gliclazide led to an improvement in control except in cases previously treated with glibenclamide. In the second study, diabetic control was compared in 112 NIDDM patients treated concurrently for one year with chlorpropamide, glipizide, gliquidone, glibenclamide or gliclazide. On the basis of HbA1 levels, the best results were obtained with glibenclamide and gliclazide, leading to normal HbA1 levels in 74% and 80% of patients, respectively. In the third study, secondary failure rates were assessed in 248 NIDDM patients treated for five years with gliclazide, glibenclamide or glipizide. Gliclazide had the lowest secondary failure rate (7%) and was significantly better than glipizide (25.6% failures in five years), but the difference relative to glibenclamide (17.9%) just failed to reach the threshold of significance. The results of these studies show that gliclazide is a potent hypoglycaemic agent which compares favourably with others of its type. It has a low incidence of side effects, few problems with hypoglycaemia, and retains its efficacy longer than other sulphonylureas. Gliclazide may therefore be considered a first choice for the therapy of diet-failed NIDDM patients.