Efficacy of metformin in type II diabetes: results of a double-blind, placebo-controlled, dose-response trial

Role of metformin in the initiation of pharmacotherapy for type 2 diabetes: an Asian-Pacific perspective

Increases in the prevalence of type 2 diabetes of 30-60% will occur in many Asian-Pacific countries by 2025, driven by urbanisation, sedentary habits and energy-rich diets. Obesity, insulin resistance, metabolic syndrome and diabetes are closely interrelated. Optimal control of diabetes and associated risk factors has reduced the risk of diabetes-related complications. In the UK Prospective Diabetes Study (UKPDS), metformin reduced the risk of macrovascular complications and retrospective analyses have confirmed the efficacy of metformin in improving clinical outcomes in type 2 diabetic patients with a history of cardiovascular disease. This growing body of evidence has led to the recommendation of metformin as optimum initial pharmacotherapy in overweight type 2 diabetic patients. Obesity is less prevalent in the Asian-Pacific population than in Caucasian populations. Nevertheless, metformin has multiple beneficial metabolic effects, which provide sufficient rationale for it to be recommended as the initial oral anti-diabetic pharmacotherapy, alone or in combination, irrespective of body mass index. This recommendation is consistent with global guidelines and regional recommendations for the Asian-Pacific region from the International Diabetes Federation. These recommendations can serve as templates for development of local guidelines for Asian people with diabetes, given the ethnic and cultural diversity within the region.

Medikamentöse Therapie des Diabetes mellitus Typ 2

The sequelae and complications associated with type 2 diabetes mellitus can be reduced or inhibited by optimal therapy. Currently, a variety of medications are available for differentiated therapy, which should be used according to the German Diabetes Association Guidelines. Changes in lifestyle represent the basic therapeutic principle, and it is mandatory to continuously maintain these measures throughout life. If this is not adequately effective (HBA(1c) <6.5%), treatment with oral antidiabetic drugs (OAD) is necessary. Over time OAD monotherapy frequently fails, so that a combination of several oral antidiabetics is needed. The choice of oral antidiabetics is particularly dependent on the patient's body mass index and associated diseases. If combination therapy with OAD is not successful in achieving HbA1c values <6.5%, insulin therapy is required either in combination with OADs as a bedtime regimen or as intensive insulin therapy using both basal and short-term acting insulins.

Relative bioavailability and bioequivalence of metforphin hydrochloride extended-released and immediate-released tablets in healthy Chinese volunteers

The aim of the present study was to investigate the relative bioavailability and bioequivalence of a new tablet formulation of metformin hydrochloride with reference to a standard product in healthy Chinese adult male volunteers. Two randomized, comparative, two-way crossover studies were therefore conducted. In study 1, which was a single-dose study, 20 subjects received 1000 mg metformin hydrochloride test product extended-release (MXR) tablets followed by the same amount of metformin hydrochloride reference product immediate-release (MIR) tablets with a 7-day washout period between the two doses. In study 2, which was a multiple-dose study, 22 subjects received MXR 1000 mg/d for 9 consecutive days followed by MIR 1000 mg/d with a 14-day washout period between the doses of the test and reference product. The serum metformin concentrations were monitored using a selective and sensitive high-performance liquid chromatography (HPLC) method with ultraviolet (UV) detection. The pharmacokinetic parameters were calculated using a 3P97 program. Analysis of variance (ANOVA) of the half-life of the absorption phase (t(1/2ka)), the half-life of the elimination phase (t(1/2ke)) and the mean retention time (MRT) and the Wilcoxon Signed Rank test of T(max) for the two preparations were significantly different. A significant difference was found in the ANOVA for C(max) in the single-dose study, while this was not the case in the multiple-dose study. Two one-sided t-tests showed that there were no significant differences in the area under the concentration-time curve (AUC) values between the two formulations. The present study indicates that the test preparation was bioequivalent to the reference preparation when both MXR and MIR were investigated in healthy Chinese adult male volunteers. And on the basis of the mean AUC(0-t), AUC(0-infinity) and AUC(ss), the relative bioavailability of the MXR was found to be 107.80%, 111.89% and 110.61% respectively compared with MIR.

Contraindications to metformin therapy among patients with type 2 diabetes mellitus

OBJECTIVE

The biguanide, metformin, is a commonly prescribed oral antihyperglycemic agent. However, there are several clinical conditions that are considered as contraindications to the use of metformin among patients with type 2 diabetes mellitus. The aim of this study was to investigate the presence and nature of contraindications to metformin therapy among patients with type 2 diabetes mellitus.

METHOD

A retrospective study of the medical files of diabetic patients available at Alwosta clinic, north Palestine was carried out. Information about disease and medication profile of the patients was retrieved and analyzed using SPSS during the study period in 2004/2005. Focus was on metformin users who have contraindications to metfromin therapy.

MAIN OUTCOME MEASURE

Presence and number of contraindications to metformin therapy.

RESULTS

Two hundred and seventy-two type 2 diabetic patients were identified. One hundred and twenty four of those diabetic patients were metformin users. Approximately, 60% of patients in the metformin group had a least one contraindication. Congestive heart failure and renal impairment were the most quantitatively present contraindications.

CONCLUSION

Contraindications to metformin therapy are common among type 2 diabetic patients and mostly disregarded. Patients have to be critically assessed before starting therapy and in case of metformin prescribing; dose should be adjusted based on the presence of risk factors for metformin adverse effects.

Traitement médicamenteux du diabète de type 2 (première partie)

Drug treatment of 2 diabetes is intended to normalize glycosylated hemoglobin levels (HbA(1c)<6.5%) and thereby prevent the development of micro- and macrovascular complications. Oral antidiabetic agents target the metabolic abnormalities that cause diabetes. The two principal families of oral antidiabetic agents - insulin sensitizers and insulin secretagogues - can be taken together. Thiazolidinediones or glitazones (insulin sensitizers) improve peripheral tissue sensitivity to insulin. Metformin (an insulin sensitizer) reduces hepatic glucose production. Sulfonylureas and meglitinides (insulin secretagogues) stimulate insulin secretion and can cause hypoglycemia. GLP-1 (Glucagon-Like Peptide-1) analogs and DPP-IV (dipeptidyl-peptidase-IV) inhibitors are new drug classes currently under development.

Trends in the prescribing of oral agents for the management of type 2 diabetes mellitus in the United States, 1990-2001: does type of insurance influence access to innovation?

PURPOSE

The objectives of the present study were (1) to discern trends in the prescribing of oral pharmacotherapy for the management of type 2 diabetes mellitus (DM) in the United States during the years 1990 through 2001 and (2) to examine the mediating role of primary health insurance coverage on patients' access to pharmaceutical innovation for the management of type 2 DM.

METHODS

Data from the US National Ambulatory Medical Care Survey (NAMCS) for the years 1990 through 2001 were used for this analysis.

RESULTS

National estimates of the number of office-based visits documenting a diagnosis of type 2 DM and the prescribing of an oral medication for glycemic control increased from 7 871 283 in 1990 to 13 730 886 in 2001 (a 74.4% increase). A significantly higher proportion of patients covered by private health insurance were prescribed a newer agent, either alone or as part of a combination regimen of oral agents, as compared to patients covered by either Medicare or Medicaid (chi(2) < or = .001).

CONCLUSIONS

Over the time frame of 1995 through 2001, access to pharmaceutical innovation for the management of type 2 DM was mediated by the patient's primary source of health insurance coverage. Future research will need to discern the effect of observed differences in the prescribing of oral agents for the management of type 2 DM on both clinical and economic outcomes and, in light of ongoing discussion regarding health care reform in the United States, to foster clinically rational and equitable access to pharmaceutical innovation.

Acute effects of metformin therapy include improvement of insulin resistance and ovarian morphology

OBJECTIVE

To evaluate the acute effects of metformin therapy on biochemical markers and polycystic ovarian morphology among insulin-resistant (IR) and noninsulin-resistant (NIR) patients with polycystic ovary syndrome (PCOS).

DESIGN

Prospective interventional study.

SETTING

Reproductive endocrinology clinic in a university hospital.

PATIENT(S)

Five IR and five NIR patients with PCOS. The mean age of patients was 29.5 +/- 4.8 years (range, 23-36 years).

INTERVENTION

Metformin therapy, using 850 mg orally per day for 1 week.

MAIN OUTCOME MEASURE(S)

Serum levels of T, FSH, and LH, fasting glucose/insulin ratio, levels of anti-Müllerian hormone (AMH) and inhibin B, and antral follicle count.

RESULT(S)

Levels of AMH and inhibin B were statistically significantly higher in patients with PCOS compared to controls (2.81 +/- 1.79 ng/mL versus 0.95 +/- 1.17 ng/mL, and 56.24 +/- 29.39 pg/mL versus 17.89 +/- 12.87 pg/mL, respectively). Levels of AMH and inhibin B were similar among IR and NIR patients with PCOS (2.77 +/- 1.92 ng/mL versus 2.85 +/- 1.89 ng/mL, and 53.96 +/- 28.58 pg/mL versus 58.51 +/- 33.28 pg/mL, respectively). One week of metformin therapy did not alter either AMH or inhibin B levels. However, there was a statistically significant increase in glucose/insulin ratios (4.59 +/- 1.57 versus 6.35 +/- 3.6), and a significant decrease in the number of antral follicles after 1 week of metformin therapy (38.8 +/- 19.3 versus 23.1 +/- 7.4).

CONCLUSION(S)

Levels of AMH and inhibin B are significantly increased in patients with PCOS compared to controls, but are not associated with insulin resistance. Low-dose metformin therapy improves IR and polycystic ovary morphology, even though levels of T, AMH, and inhibin B remain unchanged.

Comparison of glargine insulin versus rosiglitazone addition in poorly controlled type 2 diabetic patients on metformin plus sulfonylurea

OBJECTIVE

We sought to examine the mechanisms by which the addition of glargine insulin or rosiglitazone improves glycemic control in type 2 diabetic subjects poorly controlled on maximally effective doses of metformin plus sulfonylurea.

RESEARCH DESIGN AND METHODS

Subjects (aged 47 +/- 11 years, BMI 31 +/- 5 kg/m(2), HbA(1c) [A1C] 9.4 +/- 1.3%) received bedtime glargine insulin (titrated based on the fasting plasma glucose [FPG], n = 10) or rosiglitazone (4 mg twice daily, n = 10). At baseline and after 4 months, A1C was measured and an oral glucose tolerance test and a 3-h euglycemic insulin (80 mU/m(2) per min) clamp with [3-(3)H]glucose were performed.

RESULTS

A1C and FPG decreased similarly in the glargine insulin (9.1 +/- 0.4 to 7.6 +/- 0.3% and 212 +/- 14 to 139 +/- 5 mg/dl, respectively, both P < 0.0001) and rosiglitazone (9.4 +/- 0.3 to 7.6 +/- 0.4% and 223 +/- 14 to 160 +/- 19 mg/dl, respectively, both P < 0.005) groups. After 4 months, endogenous glucose production (EGP) declined similarly with glargine insulin (2.27 +/- 0.10 to 1.73 +/- 0.12 mg . kg(-1) . min(-1), P < 0.0001) and rosiglitazone (2.21 +/- 0.12 to 1.88 +/- 0.12 mg . kg(-1) . min(-1), P = 0.01). The hepatic insulin resistance index declined in the rosiglitazone group (32 +/- 3 to 21 +/- 1 mg . kg(-1) . min(-1) x microU/ml, P = 0.03 vs. baseline and P < 0.05 vs. glargine insulin) and did not change in the glargine group (22 +/- 5 to 20 +/- 3 mg . kg(-1) . min(-1) x microU/ml, P = NS). At 4 months, glargine insulin (3.6 +/- 0.5 to 4.2 +/- 0.4 mg . kg(-1) . min(-1), P < 0.01) and rosiglitazone (2.7 +/- 0.3 to 3.8 +/- 0.3 mg . kg(-1) . min(-1), P < 0.0005) increased R(d), but the increment was greater in the rosiglitazone group (P < 0.05). Diastolic blood pressure was reduced only by rosiglitazone (P < 0.01).

CONCLUSIONS

Triple therapy with glargine insulin or rosiglitazone similarly reduced A1C, primarily by suppressing basal EGP (hepatic). Glargine insulin reduced basal EGP by increasing plasma insulin levels, while rosiglitazone decreased basal hepatic glucose production by improving hepatic insulin sensitivity.

Acidose lactique et metformine

OBJECTIVE

The aims of this review are to precise the pathophysiological mechanisms leading to biguanide-associated lactic acidosis, to give elements of diagnosis, and to underline the precautionary conditions for prescribing these drugs by an improvement in physicians and patient's education.

DATA SOURCES

A PubMed database research in English and French language reports published until December 2005. The keywords were: lactic acidosis, metformin, biguanide, diabetes mellitus.

DATA EXTRACTION

Data in selected articles were reviewed, clinical and basic science research relevant informations were extracted.

DATA SYNTHESIS

Metformin, which is an oral antidiabetic agent, is the only one biguanide available in France. It acts by enhancing the sensitivity to insulin by a decrease in the hepatic glucose production and an increase in its peripheral use. In term of glycemic control, it has the same efficiency than the other hypoglycemic agents. It represents the treatment of choice for overweight type 2 diabetic patients because of its beneficial effects on the weight loss and on the cardiovascular complications. The incidence of metformin-associated lactic acidosis is very low when contra-indications and appropriate rules for prescribing this drug are respected. The relationship between metformin and lactic acidosis remains largely controversial. In practical, we can distinguish three situations which have different prognosis. In the first case, metformin seems to be responsible for lactic acidosis because of self-poisoning or accidental overdose, and prognosis is good. In the second case, the association between metformin and lactic acidosis is coincidental rather than causal, and may be induced by an underlying organ failure. In the last case there is a cause of lactic acidosis which is worsened by a precipitating factor leading to metformin accumulation. The 2 latter situations are very severe as mortality rate is about 50%. Symptomatic treatments and renal replacement therapy which allows metformin removal are the curative treatment. Prevention is essential. It requires the respect of metformin contraindications and a better education of physicians and patients for a safe prescription.

CONCLUSION

Due to its beneficial effects, metformin is the gold standard treatment for overweight type 2 diabetic patients. The essential precautionary conditions for prescribing metformin as well as the respect of its contra-indications permit largely to prevent lactic acidosis. This complication is serious when it is associated with intercurrent illnesses and metformin accumulation. The curative treatment is based on renal replacement therapy. Prevention only rests on the respect of the contra-indications. Education of physicians and patients concerning the rules of prescription remains essential.

Effect of metformin plus roziglitazone compared with metformin alone on glycaemic control in well-controlled Type 2 diabetes

AIMS

To investigate the effect of metformin plus roziglitazione (RSGMET) compared with metformin alone (MET) on glycaemic control in well-controlled Type 2 diabetes.

METHODS

Subjects (drug naïve or those on glucose-lowering monotherapy) were randomized (n = 526), following a 4-week placebo run-in period, to RSGMET [4 mg rosiglitazone (RSG)/500 mg MET] or MET 500 mg. From weeks 2-18, medication was escalated every 4 weeks (based on gastrointestinal tolerability), then remained at RSGMET 8 mg/2 g or MET 3 g for 14 weeks.

RESULTS

RSGMET reduced HbA(1c) from 7.2 +/- 0.6 to 6.7 +/- 0.8% at week 32, compared with a reduction from 7.2 +/- 0.6 to 6.8 +/- 0.9% with MET (treatment difference -0.13%; P = 0.0357). More subjects achieved an HbA(1c) value of </= 6.5% at week 32 with RSGMET (51.6 vs. 43.7%), but the treatment difference was not significant (odds ratio 1.37, P = 0.0949). RSGMET produced larger reductions from baseline in mean fasting plasma glucose (adjusted difference -0.62 mmol/l, P < 0.0001), with the odds ratio of achieving a target of < 7.0 mmol/l being 2.33 (P < 0.0001). Statistically significant differences in favour of RSGMET relative to MET were seen for homeostatic model assessment (HOMA)-derived estimates of insulin sensitivity and pancreatic B-cell function, C-reactive protein (CRP), and systolic blood pressure. Overall rates of gastrointestinal adverse events (relevant to the known profile of MET) were comparable, but with a lower incidence of diarrhoea (8 vs. 18%) with RSGMET. Hypoglycaemia was reported in </= 7% subjects per group.

CONCLUSIONS

RSGMET provided similar short-term glycaemic control to MET with greater improvements in estimates of insulin sensitivity, B-cell function and CRP, with less diarrhoea and low risk of biochemical hypoglycaemia, suggesting that early use of combination therapy may be appropriate.

Obesity

There is a widespread epidemic of obesity in the United States, which has been associated with an increased risk of diabetes mellitus, cancer, and cardiovascular diseases. Although lifestyle modifications and long-term dietary vigilance remain cornerstones of weight reduction treatment, the continued availability of U.S. Food and Drug Administration-approved pharmacotherapies has expanded the options available for the management of obesity. These agents include anorexiants, thermogenic drugs, and lipid-partitioning drugs. As knowledge regarding the possible causes of obesity increases, there are new drugs under investigation, which include beta3-adrenergic receptor agonists, modifiers of leptin, and cannabinoid receptor-1 antagonists (rimonabant). Also under investigation are antidiabetic agents (metformin, exenatide), anticonvulsant drugs (topiramate, zonisamide), antidepressants (bupropion, fluoxetine), and growth hormones. New targets for pharmacotherapy include uncoupling proteins, fatty acid synthase, neuropeptide Y, melanocortin, ghrelin, various regulatory gut peptides, and ciliary neurotropic factor. Pharmacologic agents are in clinical development that target these substances.

Effect of clomifene citrate plus metformin and clomifene citrate plus placebo on induction of ovulation in women with newly diagnosed polycystic ovary syndrome: randomised double blind clinical trial

OBJECTIVE

To compare the effectiveness of clomifene citrate plus metformin and clomifene citrate plus placebo in women with newly diagnosed polycystic ovary syndrome.

DESIGN

Randomised clinical trial.

SETTING

Multicentre trial in 20 Dutch hospitals.

PARTICIPANTS

228 women with polycystic ovary syndrome.

INTERVENTIONS

Clomifene citrate plus metformin or clomifene citrate plus placebo.

MAIN OUTCOME MEASURE

The primary outcome measure was ovulation. Secondary outcome measures were ongoing pregnancy, spontaneous abortion, and clomifene resistance.

RESULTS

111 women were allocated to clomifene citrate plus metformin (metformin group) and 114 women were allocated to clomifene citrate plus placebo (placebo group). The ovulation rate in the metformin group was 64% compared with 72% in the placebo group, a non-significant difference (risk difference - 8%, 95% confidence interval - 20% to 4%). There were no significant differences in either rate of ongoing pregnancy (40% v 46%; - 6%, - 20% to 7%) or rate of spontaneous abortion (12% v 11%; 1%, - 7% to 10%). A significantly larger proportion of women in the metformin group discontinued treatment because of side effects (16% v 5%; 11%, 5% to 16%).

CONCLUSION

Metformin is not an effective addition to clomifene citrate as the primary method of inducing ovulation in women with polycystic ovary syndrome.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN55906981 [controlled-trials.com].

Efficacy, tolerability, and safety of a novel once-daily extended-release metformin in patients with type 2 diabetes

OBJECTIVE

The purpose of this study was to determine the efficacy and safety of a novel extended-release metformin in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Adults with type 2 diabetes (newly diagnosed, treated with diet and exercise only, or previously treated with oral diabetic medications) were randomly assigned to receive one of three extended-release metformin treatment regimens (1,500 mg/day q.d., 1,500 mg/day twice daily, or 2,000 mg/day q.d.) or immediate-release metformin (1,500 mg/day twice daily) in a double-blind 24-week trial.

RESULTS

Significant decreases (P < 0.001) in mean HbA(1c) (A1C) levels were observed by week 12 in all treatment groups. The mean changes from baseline to end point in the two groups given 1,500 mg extended-release metformin (-0.73 and -0.74%) were not significantly different from the change in the immediate-release metformin group (-0.70%), whereas the 2,000-mg extended-release metformin group showed a greater decrease in A1C levels (-1.06%; mean difference [2,000 mg extended-release metformin - immediate-release metformin]: -0.36 [98.4% CI -0.65 to -0.06]). Rapid decreases in fasting plasma glucose levels were observed by week 1, which continued until week 8, and were maintained for the duration of the study. The overall incidence of adverse events was similar for all treatment groups, but fewer patients in the extended-release metformin groups discontinued treatment due to nausea during the initial dosing period than in the immediate-release metformin group.

CONCLUSIONS

Once- or twice-daily extended-release metformin was as safe and effective as twice-daily immediate-release metformin and provided continued glycemic control for up to 24 weeks of treatment.

Metformin extended release for the treatment of Type 2 diabetes mellitus

Metformin extended release (ER) (Glumetza, Depomed, Inc.) is a recently approved formulation that provides effective and well-tolerated glycaemic control with once-daily dosing. Metformin ER has similar bioavailability to conventional immediate-release (IR) formulations. In controlled clinical trials, metformin ER provided effective glycaemic control for 24 weeks when administered either as monotherapy or in combination with sulfonylurea. Good glycaemic control was maintained for an additional 24 weeks during an open-label extension study. Once-daily dosing with metformin ER 1500 mg/day was as effective as twice-daily dosing with metformin IR at the same total daily dose. Metformin ER was well tolerated at doses of 1500 or 2000 mg/day, with no increase in the frequency or severity of adverse events at the higher dose.

Rosiglitazone/metformin fixed-dose combination compared with uptitrated metformin alone in type 2 diabetes mellitus: a 24-week, multicenter, randomized, double-blind, parallel-group study

BACKGROUND

Management of type 2 diabetes mellitus (DM) that involves uptitration of monotherapy to the maximum dose has been associated with delays in achieving glycemic control and an increased number of adverse events (AEs). Studies have reported the benefits of adding a thiazolidinedione to metformin (MET), but none has compared the effect of adding a thiazolidinedione to MET versus increasing the daily dose of MET to 3 g.

OBJECTIVE

The goal of this study was to investigate the benefits of fixed-dose combination rosiglitazone and MET (RSG/MET) compared with high-dose MET monotherapy in patients with type 2 DM.

METHODS

This was a 24-week, multicenter, randomized, double-blind, parallel-group study. Patients previously treated with MET entered a 4-week, single-blind, run-in period with MET 2 g/d and were then randomized to RSG/MET 4 mg/2 g per day or MET 2.5 g/d. At week 8, medication was escalated to RSG/MET 8 mg/2 g per day or MET 3 g/d. The primary efficacy end point was change in glycosylated hemoglobin (HbA1c) at week 24. Tolerability was assessed, including the frequency and severity of AEs.

RESULTS

A total of 568 patients comprised the safety population (MET, 280; RSG/MET, 288) and 551 formed the intent-to-treat group (MET, 272; RSG/MET, 279). Baseline characteristics of the safety population were comparable in the 2 groups; body mass index (mean [SD]) was 32.2 (4.8) kg/m(2) and 32.1 (4.9) kg/m(2) in the RSG/MET and MET groups, respectively. RSG/MET reduced HbA(1c) (mean [SD]) from 7.4% (1.0%) to 7.1% (1.1%) at week 24, compared with a reduction from 7.5% (1.0%) to 7.4% (1.1%) with MET (treatment difference, -0.22%; P = 0.001). Fasting plasma glucose (mean [SD]) was reduced from 166.2 (29) to 144.1 (33) mg/dL with RSG/MET and from 169.3 (33) to 164.0 (37) mg/dL with MET (treatment difference, -18.3 mg/dL; P < 0.001). In addition, 54% of patients treated with RSG/MET achieved HbA(1c) levels <7.0%, compared with 36% with MET (odds ratio, 2.42; P < 0.001). RSG/MET increased homeostasis model assessment (HOMA) estimates of insulin sensitivity by 34.4% versus 6.5% with MET (treatment difference, 24.8%; P < 0.001). HOMA beta-cell function increased by 15.9% with RSG/MET versus 2.5% with MET (treatment difference, 14.0%; P < 0.001). RSG/MET decreased C-reactive protein by a mean of 39.4% versus 16.0% with MET (treatment difference, -33.8%; P < 0.001). RSG/MET was generally well tolerated, with the majority of AEs mild to moderate in nature. Serious AEs were reported in 3% of patients receiving RSG/MET and 2% with MET. Overall rates of gastrointestinal AEs were 23% with RSG/MET and 26% with MET; however, there was an increased incidence of diarrhea (14% vs 6%) and abdominal pain (9% vs 6%) with MET. There was a mean (SE) increase in weight with RSG/MET (1.3 [0.22] kg) and a mean decrease (-0.9 [0.26] kg) with MET. Patients receiving RSG/MET reported improvements in treatment satisfaction compared with MET.

CONCLUSIONS

In this study, the RSG/MET fixed-dose combination (8 mg/2 g per day) was an effective and well-tolerated treatment for type 2 DM and enabled more patients to reach glycemic targets than high-dose MET (3 g/d).

Risk of fatal and nonfatal lactic acidosis with metformin use in type 2 diabetes mellitus

BACKGROUND

Metformin is an oral anti-hyperglycemic agent used in the treatment of type 2 diabetes mellitus. The results of the UK Prospective Diabetes Study indicate that metformin treatment is associated with a reduction in total mortality compared to other anti-hyperglycemic treatments. Metformin, however, is thought to increase the risk of lactic acidosis, and is considered to be contraindicated in many chronic hypoxemic conditions that may be associated with lactic acidosis, such as cardiovascular, renal, hepatic and pulmonary disease, and advancing age.

OBJECTIVES

To assess the incidence of fatal and nonfatal lactic acidosis with metformin use compared to placebo and other glucose-lowering treatments in patients with type 2 diabetes mellitus. A secondary objective was to evaluate the blood lactate levels for those on metformin treatment compared to placebo or non-metformin therapies.

SEARCH STRATEGY

A search was performed of The Cochrane Library (up to 8/2005), MEDLINE (up to 8/2005), EMBASE (up to 11/2000), OLD MEDLINE, and REACTIONS (up to 8/2005), in order to identify all studies of metformin treatment from 1966 to August 2005. The Cumulated Index Medicus was used to search relevant articles from 1959 to 1965. The search was augmented by scanning references of identified articles, and by contacting principal investigators. Date of latest search: August 2005.

SELECTION CRITERIA

Prospective trials in patients with type 2 diabetes that lasted longer than one month were included if they evaluated metformin, alone or in combination with other treatments, compared to placebo or any other glucose-lowering therapy. Observational cohort studies of metformin treatment lasting greater than one month were also included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected trials to be included, assessed study quality and extracted data. The incidence of fatal and nonfatal lactic acidosis was recorded as cases per patient-years, for metformin treatment and for placebo or other treatments. The upper limit for the true incidence of cases in the metformin and non-metformin groups were calculated using Poisson statistics. In a second analysis lactate levels were measured as a net change from baseline or as mean treatment values (basal and stimulated by food or exercise) for treatment and comparison groups. The pooled results were recorded as a weighted mean difference (WMD) in mmol/L, using the fixed effect model for continuous data.

MAIN RESULTS

Pooled data from 206 comparative trials and cohort studies revealed no cases of fatal or nonfatal lactic acidosis in 47,846 patient-years of metformin use or in 38,221 patients-years in the non-metformin group. Using Poisson statistics with 95% confidence intervals the upper limit for the true incidence of metformin-associated lactic acidosis was 6.3 cases per 100,000 patient-years, and the upper limit for the true incidence of lactic acidosis in the non-metformin group was 7.8 cases per 100,000 patient-years. There was no difference in lactate levels, either as mean treatment levels or as a net change from baseline, for metformin compared to placebo or other non-biguanide therapies. The mean lactate levels were slightly lower for metformin treatment compared to phenformin (WMD -0.75 mmol/L, 95% CI -0.86 to -0.15).

AUTHORS' CONCLUSIONS

There is no evidence from prospective comparative trials or from observational cohort studies that metformin is associated with an increased risk of lactic acidosis, or with increased levels of lactate, compared to other anti-hyperglycemic treatments if prescribed under the study conditions.

A model of long-term metabolic progression of type 2 diabetes mellitus for evaluating treatment strategies

AIM

To develop a novel metabolic computer model of the natural lifetime progression of type 2 diabetes that generates dynamic risk factor trajectories consistent with prespecified lifetime therapeutic strategies, in order to enhance the long-term economic and outcome modelling of type 2 diabetes and its complications.

METHODS

The main model drivers of progressive disease were changes in insulin sensitivity and islet beta-cell function derived from an analysis of follow-up results from the Belfast Diet Study. These were related to clinical measures through an adaptation of the homeostasis model assessment. Established causal relationships estimating body mass index, lipids and blood pressure from measures of glycaemia and plasma insulin were calibrated using Third National Health and Nutrition Examination Survey (USA) data, standardizing for age, sex, ethnicity and smoking. The effects of individual interventions were calibrated using published trial evidence, in line with the current understanding of the main modes of action of each agent.

RESULTS

A comparison of the effects of common therapies using the model showed both similarities and differences. Large improvements in glycaemic control from lifestyle modifications, further enhanced by oral glucose-lowering drugs or insulin, were reproduced. Projections comparing lifetime therapeutic strategies suggest that simple guidelines may not always be valid.

CONCLUSION

This novel mathematical model using evidence from the long-term natural history of type 2 diabetes is able to project the expected effects of various antihyperglycaemic therapies. Coupled with an economic model, this metabolic model may provide a mechanism for healthcare professionals and policymakers to evaluate different long-term strategies for the management of type 2 diabetes.

Metformin and pioglitazone: Effectively treating insulin resistance

BACKGROUND

Insulin resistance has a complex etiology, with multiple manifestations across the organ systems involved in glucose homeostasis. Glucose-lowering drug therapies that target insulin resistance can therefore utilize different mechanistic approaches. Two key classes of insulin-sensitizing agents--the biguanides (principally metformin) and thiazolidinediones (pioglitazone and rosiglitazone)--have distinct molecular mechanisms of action and differing effects on metabolic dysfunction. This provides an opportunity for complementary beneficial effects in the treatment of type 2 diabetes and on the potential consequences of insulin resistance, such as dyslipidemia and atherosclerosis.

SCOPE

This review (based upon EMBASE and MEDLINE searches from January 1990 to April 2006) highlights the mechanistic distinctions and clinical data that support the rationale for thiazolidinedione/metformin combination therapy in patients with type 2 diabetes.

FINDINGS

The different insulin-sensitizing mechanisms of metformin and the thiazolidinediones are manifest in partially distinct effects on hepatic and peripheral glucose homeostasis, and clinical studies show improved glucose control with combination therapy. Both metformin and thiazolidinediones may also have pancreatic beta-cell preserving properties. Furthermore, they have different beneficial effects on several other metabolic risk markers and risk factors for cardiovascular disease. Whereas the thiazolidinediones (particularly pioglitazone) have greater effects on multiple aspects of dyslipidemia, metformin has anorexigenic properties. They also have distinct effects on levels of mediators involved in inflammation and endothelial dysfunction, and outcome studies suggest that either pioglitazone or metformin may reduce the risk of macrovascular events.

CONCLUSION

The distinct, but complementary, mechanisms of action of the thiazolidinediones and metformin provide the opportunity for effective combination therapy with two insulin-sensitizing agents. Such an approach has consequences, not only for improved glucose control, but also for reducing metabolic risk and potentially improving major cardiovascular disease outcomes.

Combination therapy using metformin or thiazolidinediones and insulin in the treatment of diabetes mellitus

The biguanide, metformin, sensitizes the liver to the effect of insulin, suppressing hepatic glucose output. Thiazolidinediones such as rosiglitazone and pioglitazone enhance insulin-mediated glucose disposal, leading to reduced plasma insulin concentrations. These classes of drugs may also have varying beneficial effects on features of insulin resistance such as lipid levels, blood pressure and body weight. Metformin in combination with insulin has been shown to significantly improve blood glucose levels while lowering total daily insulin dose and body weight. The thiazolidinediones in combination with insulin have also been effective in lowering blood glucose levels and total daily insulin dose. Triple combination therapy using insulin, metformin and a thiazolidinedione improves glycaemic control to a greater degree than dual therapy using insulin and metformin or insulin and a thiazolidinedione. There is insufficient evidence to recommend the use of metformin or thiazolidinediones in type 1 diabetic patients. Although these agents are largely well tolerated, some subjects experience significant gastrointestinal problems while using metformin. Metformin is associated with a low risk of lactic acidosis, but should not be used in patients with elevated serum creatinine or those being treated for congestive heart failure. The thiazolidinediones are associated with an increase in body weight, although this can be avoided with careful lifestyle management. Thiazolidinediones may also lead to oedema and are associated with a low incidence of hepatocellular injury. Thiazolidinediones are contraindicated in patients with underlying heart disease who are at risk of congestive heart failure and in patients who have abnormal hepatic function. The desired blood glucose-lowering effect and adverse event profiles of these agents should be considered when recommending these agents to diabetic patients. The potential for metformin or the thiazolidinediones to impact long-term cardiovascular outcomes remains under investigation.

Metformin revisited: re-evaluation of its properties and role in the pharmacopoeia of modern antidiabetic agents

BACKGROUND

The usefulness of metformin as an oral antidiabetic agent is widely accepted. However, several other classes of oral antidiabetic agents have been recently introduced, raising the need to evaluate the role of metformin as initial therapy and in combination with these newer drugs for treatment of type 2 diabetes mellitus (DM).

METHODS

Synthesis of information was preceded by a comprehensive review of the English language literature using Medline. We also reviewed bibliographies of relevant articles. The studies most pertinent to the mechanism of action, efficacy, toxicity and administration of metformin were selected for citation in this review.

RESULTS

Metformin acts by increasing tissue sensitivity to insulin, principally in the liver. Beneficial properties of metformin include weight reduction, favourable effects on the lipid profile and the fibrinolytic pathway, and improvement of ovarian function in some insulin-resistant women. It does not cause hyperinsulinaemia or hypoglycaemia. Metformin is effective as monotherapy and, in combination with both insulin secretagogues and thiazolidinediones (TZDs), may obviate the need for insulin treatment. Several fixed-dose combination pills containing metformin and other agents are available. A protocol for the initiation of therapy with contemporary oral agents for type 2 DM is presented, with emphasis on the continuing central role of metformin.

CONCLUSIONS

Metformin remains a safe and effective agent for the therapy of patients with type 2 DM. It is useful as monotherapy or in combination regimens with the newer insulin secretagogues, TZDs or insulin. It is still in most circumstances the agent of choice for initial therapy of the typical obese patient with type 2 DM and mild to moderate hyperglycaemia.

Effects of liraglutide (NN2211), a long-acting GLP-1 analogue, on glycaemic control and bodyweight in subjects with Type 2 diabetes

AIMS

Liraglutide (NN2211) is a long-acting GLP-1 analogue, with a pharmacokinetic profile suitable for once-daily administration. This multicentre, double-blind, parallel-group, double-dummy study explored the dose-response relationship of liraglutide effects on bodyweight and glycaemic control in subjects with Type 2 diabetes.

METHODS

Subjects (BMI 27-42 kg/m(2)) with Type 2 diabetes who were previously treated with an OAD (oral anti-diabetic drug) monotherapy (69% with metformin), and had HbA(1c) < or = 10% were enrolled. After a 4-week metformin run-in period, 210 subjects (27-73 years, 60% female) were randomised to receive liraglutide (0.045-0.75 mg) once daily or continued on metformin 1000 mg b.d. for 12 weeks.

RESULTS

Mean baseline values for the six treatment groups ranged from 6.8 to 7.5% for HbA(1c), and 8.06-9.44 mmol/l (145-170 mg/dl) for fasting plasma glucose. After 12-week treatment, a weight change of -0.05 to -1.9% was observed for the six treatment groups. Mean HbA(1c) changes from baseline for 0.045, 0.225, 0.45, 0.6, 0.75 mg liraglutide and metformin were +1.28%, +0.86%, +0.22%, +0.16%, +0.30% and +0.09%, respectively. No significant differences in HbA(1c) were observed between liraglutide and metformin groups at the three highest liraglutide dose levels (0.45, 0.6 and 0.75 mg). The lowest two liraglutide doses (0.045 mg and 0.225 mg) were not sufficient to maintain the fasting plasma glucose values achieved by metformin. No major hypoglycaemic episodes were reported. Episodes of nausea and/or vomiting were reported by 11 patients (6.3%) receiving liraglutide and three (8.8%) receiving metformin.

CONCLUSIONS

Once-daily liraglutide improved glycaemic control and weight, in a comparable degree to metformin. Liraglutide appeared to be safe and generally well tolerated. Higher doses of liraglutide merit study in future clinical trials.

Metformin monotherapy for type 2 diabetes mellitus

BACKGROUND

Metformin is an anti-hyperglycaemic agent used for the treatment of type 2 diabetes mellitus. Type 2 diabetes may present long-term complications: micro- (retinopathy, nephropathy and neuropathy) and macrovascular (stroke, myocardial infarction and peripheral vascular disease). Two meta-analyses have been published before, although only secondary outcomes were assessed.

OBJECTIVES

To assess the effects of metformin monotherapy on mortality, morbidity, quality of life, glycaemic control, body weight, lipid levels, blood pressure, insulinaemia, and albuminuria in patients with type 2 diabetes mellitus.

SEARCH STRATEGY

Studies were obtained from computerised searches of multiple electronic databases and hand searches of reference lists of relevant trials identified. Date of last search: September 2003.

SELECTION CRITERIA

Trials fulfilling the following inclusion criteria: Diabetes mellitus type 2, metformin versus any other oral intervention, assessment of relevant clinical outcome measures, use of random allocation.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data, using a standard data extraction form. Data were summarised under a random effects model. Dichotomous data were expressed as relative risk. We calculated the risk difference (RD), and the Number Needed to Treat, when it was possible. We collected data of mean and standard deviation from changes to baseline. However many trials reported end point data. This limitation lead to the expression of the results as standardised mean differences (SMD) and an overall SMD was calculated. Heterogeneity was tested for using the Z score and the I-squared statistic. Subgroup, sensitivity analysis and meta-regression were used to explore heterogeneity.

MAIN RESULTS

We included for analysis 29 trials with 37 arms (5259 participants), comparing metformin (37 arms and 2007 participants) with sulphonylureas (13 and 1167), placebo (12 and 702), diet (three and 493), thiazolidinediones (three and 132), insulin (two and 439), meglitinides (two and 208), and glucosidase inhibitors (two and 111). Nine studies reported data on primary outcomes. Obese patients allocated to intensive blood glucose control with metformin showed a greater benefit than chlorpropamide, glibenclamide, or insulin for any diabetes-related outcomes (P = 0.009), and for all-cause mortality (P = 0.03). Obese participants assigned to intensive blood glucose control with metformin showed a greater benefit than overweight patients on conventional treatment for any diabetes-related outcomes (P = 0.004), diabetes-related death (P = 0.03), all-cause mortality (P = 0.01), and myocardial infarction (P = 0.02). Patients assigned to metformin monotherapy showed a significant benefit for glycaemia control, weight, dyslipidaemia, and diastolic blood pressure. Metformin presents a strong benefit for HbA1c when compared with placebo and diet; and a moderated benefit for: glycaemia control, LDL cholesterol, and BMI or weight when compared with sulphonylureas.

AUTHORS' CONCLUSIONS

Metformin may be the first therapeutic option in the diabetes mellitus type 2 with overweight or obesity, as it may prevent some vascular complications, and mortality. Metformin produces beneficial changes in glycaemia control, and moderated in weight, lipids, insulinaemia and diastolic blood pressure. Sulphonylureas, alpha-glucosidase inhibitors, thiazolidinediones, meglitinides, insulin, and diet fail to show more benefit for glycaemia control, body weight, or lipids, than metformin.

Oral Antihyperglycemic Agents and Renal Disease: New Agents, New Concepts: Table 1

The results of the Diabetes Control and Complications Trial (DCCT) and UK Prospective Diabetes Study trials in type 1 and type 2 diabetes, respectively, have proved the importance of intensive glucose management in the prevention of microvascular complications (retinopathy, nephropathy, and neuropathy). Both trials showed encouraging trends for a decrease in macrovascular complications, and this is being pursued in new studies. These findings have led to more strict goals for glucose control. As glucose levels are aimed to be closer to the normal range, the risk for hypoglycemia also increases dramatically. The choice of the agent therefore is more influenced currently by the risk for hypoglycemia. There are presently four classes of oral antihyperglycemic agents. These agents differ greatly in terms of mechanisms of action, efficacy, side effect profiles, and cost. Except for Acarbose, all classes decrease the glycosylated hemoglobin by a similar magnitude: 1.0 to 1.5%. In chronic renal failure, the oral agents that can be used therefore include the insulin secretagogues repaglinide and nateglinide and the thiazolidinediones (rosiglitazone and pioglitazone) with caution. Insulin also can be used safely in renal failure.

Effects of metformin and rosiglitazone treatment on insulin signaling and glucose uptake in patients with newly diagnosed type 2 diabetes: a randomized controlled study

The effect of metformin or rosiglitazone monotherapy versus placebo on insulin signaling and gene expression in skeletal muscle of patients with newly diagnosed type 2 diabetes was determined. A euglycemic-hyperinsulinemic clamp, combined with skeletal muscle biopsies and glucose uptake measurements over rested and exercised muscle, was performed before and after 26 weeks of metformin (n = 9), rosiglitazone (n = 10), or placebo (n = 11) treatment. Insulin-mediated whole-body and leg muscle glucose uptake was enhanced 36 and 32%, respectively, after rosiglitazone (P < 0.01) but not after metformin or placebo treatment. Insulin increased insulin receptor substrate 1 (IRS-1) tyrosine phosphorylation, IRS-1-associated phosphatidylinositol (PI) 3-kinase activity, and phosphorylation of Akt Ser473 and AS160, a newly described Akt substrate that plays a role in GLUT4 exocytosis, approximately 2.3 fold before treatment. These insulin signaling parameters were unaltered after metformin, rosiglitazone, or placebo treatment. Expression of selected genes involved in glucose and fatty acid metabolism in skeletal muscle was unchanged between the treatment groups. Low-intensity acute exercise increased insulin-mediated glucose uptake but was without effect on insulin signaling. In conclusion, the insulin-sensitizing effects of rosiglitazone are independent of enhanced signaling of IRS-1/PI 3-kinase/Akt/AS160 in patients with newly diagnosed type 2 diabetes.

Antithrombotic Effects of Rosiglitazone-Metformin versus Glimepiride-Metformin Combination Therapy in Patients with Type 2 Diabetes Mellitus and Metabolic Syndrome

STUDY OBJECTIVE

To evaluate the differential effect on coagulation and fibrinolysis parameters of combination therapy with glimepiride-metformin and with rosiglitazone-metformin beyond their effect on glucose metabolism in patients with type 2 diabetes and metabolic syndrome.

DESIGN

Multicenter, double-blind, randomized, controlled trial.

SETTING

Two university-affiliated medical centers in Italy.

PATIENTS

Ninety-five patients with type 2 diabetes for at least 6 months without glycemic control by diet and oral hypoglycemic agents to their maximum tolerated dosage and who also had metabolic syndrome.

INTERVENTION

All 95 patients received metformin 1500 mg/day. In a randomized manner, 47 patients received glimepiride 2 mg/day and 48 patients received rosiglitazone 4 mg/day.

MEASUREMENTS AND MAIN RESULTS

Body mass index (BMI), glycemic control, and coagulation and fibrinolysis parameters were evaluated at 3, 6, 9, and 12 months of treatment. Compared with baseline values, significant decreases in BMI, fasting plasma glucose, postprandial plasma glucose, and hemoglobin A1c were observed at 12 months in both the glimepiride and rosiglitazone groups (p<0.05 and p<0.01, respectively). Decreases in fasting plasma insulin and postprandial plasma insulin were observed at 12 months (p<0.05 and p<0.01, respectively) compared with baseline values in the rosiglitazone group. Furthermore, improvement in the Homeostasis Model Assessment index was observed only at 9 and 12 months (p<0.05 and p<0.01, respectively) compared with baseline in the rosiglitazone group. Significant improvement in plasminogen activator inhibitor (PAI)-1 was present in the rosiglitazone group after 9 months (p<0.05), and significant PAI-1 improvement was observed in the glimepiride and rosiglitazone groups after 12 months (p<0.05 and p<0.01, respectively).

CONCLUSIONS

The rosiglitazone-metformin combination significantly improved the long-term control of all insulin resistance-related parameters compared with the glimepiride-metformin combination. However, both combinations were associated with a slight but statistically significant improvement in PAI-1 value, related to a similar reduction in insulin resistance.

How to select and combine oral agents for patients with type 2 diabetes mellitus

The increased number of oral agents available to treat patients with type 2 diabetes mellitus (DM) has presented clinicians with choices about how to combine them when monotherapy is not adequate to achieve glycemic targets. Initial studies focused on whether a combination of 2 active drugs was better than a single active agent plus placebo. Several factors need to be considered before results of combination regimens from a given protocol can be compared with results from a different study regimen. Some of these factors include population characteristics, baseline control and prior therapies, length of study, and outcomes (glycemic and nonglycemic). Additional factors to be considered are costs and side effects. These studies generally demonstrate that combination therapy is more likely than monotherapy to achieve glucose control in patients not at glycemic targets. The data also demonstrate that inadequate glucose control with a given medication does not necessarily indicate drug failure; indeed, adding a new agent to an existing regimen is typically better than using the new agent as monotherapy. More recent studies have begun to compare regimens each containing 2 drugs (usually with 1 medication in common). Outcomes beyond glycemic control have been measured, including traditional (e.g., lipid profiles, albuminuria) and nontraditional (e.g., high-sensitivity C-reactive protein, plasminogen activator inhibitor type-1) markers. However, modifying traditional markers with these medications has not yet been shown to improve outcomes; modifying nontraditional markers is even less certain. None of these trials have been extended long enough to report on hard clinical end points. Nonetheless, certain combinations may end up being preferable because they have better impact on nonglycemic end points while maintaining equivalent degrees of glucose control. Finally, the costs of multiple medications for DM need to be weighed in the decision-making process faced by clinicians.

Evaluation of drug therapy and risk factors in diabetic hypertensives: a study of the quality of care provided in diabetic clinics in Bahrain

OBJECTIVE

To evaluate control of blood pressure (BP) and diabetes and the associated risk factors in diabetic hypertensives treated by diabetic clinic primary care physicians.

METHODS

A retrospective analysis of the medical records of diabetic hypertensives from six primary care diabetic clinics in Bahrain.

RESULTS

The recommended BP target <130/<85 mmHg and of glycosylated haemoglobin (HbA1C) <7% were achieved in 7.5% and 14.5%, respectively. Most of the patients with uncontrolled BP and HbA(1C) were at high cardiovascular risk. More patients were on antihypertensive monotherapy than on combination therapy (60.6% vs. 36.7%; P<0.0001). The recommended two- and three-antihypertensive drug combinations were less often prescribed. In high-risk patients glycaemic control achieved was poor: antidiabetic combination therapy vs. monotherapy did not significantly differ. Inappropriate prescribing practices, such as the use of immediate-release nifedipine monotherapy, use of sulphonylurea instead of metformin in obese patients, and a trend towards prescribing of glyburide rather than a gliclazide in the elderly, were observed. Lipid-lowering (13.5%) and antiplatelet (12.8%) drugs were infrequently prescribed.

CONCLUSIONS

Hypertension and diabetes in patients treated at the primary care diabetic clinics were inadequately controlled. In several instances, mono- and combination antihypertensives prescribed were irrational. Lipid-lowering and platelet aggregation inhibition strategies have received little attention. Intensive antihypertensive and antidiabetic complementary combination therapy should be encouraged. Continuous professional education of diabetic clinic physicians and expert-supervised diabetic clinics are desirable.

Glycemic management of type 2 diabetes: an emerging strategy with oral agents, insulins, and combinations

The many antihyperglycemic preparations are best used for type 2 diabetes in a logical sequence, using combinations of agents, with clear targets for glycemic control. On the basis of long familiarity, proven benefit and known side effects, and low cost, the sulfonylureas, metformin, and insulin still deserve to be the standard treatments. As shown in the central shaded area of Fig. 4, standard treatment begins with monotherapy and progresses to oral combination therapy and then to two oral agents plus basal insulin. Several triggers for deviation from the standard methods are identified (see Fig. 4). The incidence of each of the conditions that require early individualized treatment has not been studied, but it seems reasonable to estimate no more than 10% each for a strongly symptomatic presentation, inability to use a sulfonylurea or metformin, inability to use insulin, or an early need for prandial therapy. If this estimate is correct, approximately two thirds of patients who are diagnosed with type 2 diabetes should do well with standard therapy for up to 10 years using the standard methods shown. Eventually, many more will need individualized treatment to maintain glycemic control. This scheme is certain to evolve as further information on the nonglycemic benefits (or hazards) of the various therapies appears and as new treatments are released. Notably, agents that mimic or potentiate the effects of gastrointestinal peptides, such as amylin and GLP- 1 analogues and dipeptidyl peptidase IV inhibitors, are likely to alter the current algorithm. For now, systematic application of the scheme (see Fig. 4) should improve the success of treatment greatly from its currently disappointing level.

Oral antihyperglycemic therapy for type 2 diabetes mellitus

Diabetes mellitus is a chronic disease that is growing in prevalence worldwide. Pharmacologic therapy is often necessary to achieve optimal glycemic control in the management of diabetes. Orally administered antihyperglycemic agents (OHAs) can be used either alone or in combination with other OHAs or insulin. The number of available OHAs has increased significantly in the last decade, which translates into more therapeutic options and complex decision-making for physicians. This review article is designed to help with these decisions. We review the mechanism of action, efficacy and side effects of the different classes of OHAs (alpha-glucosidase inhibitors, biguanides, insulin secretagogues, insulin sensitizers and intestinal lipase inhibitor) and discuss the current recommendations for their use.

Management of Diabetes Mellitus Medications in the Nursing Home

Nursing home staff are well aware of the increasing number of residents who experience diabetes mellitus. These residents consume an inordinate amount of resources and often have major disabilities and co-morbidities. Although nonpharmacological therapies, such as consistent carbohydrate intake and increased activity levels, are always indicated in diabetes management, pharmacological therapies are often necessary to prevent the acute complications of diabetes and delay some of the long-term complications. Residents with type 2 diabetes may be managed with oral antidiabetic agents and insulin, whereas residents with type 1 diabetes will always require insulin. Oral antidiabetic agents include insulin secretagogues, which stimulate endogenous insulin secretion and are most effective in leaner persons with type 2 diabetes. Metformin is another oral antidiabetic agent; this decreases inappropriate hepatic glucose release and is most effective in obese residents with high fasting blood glucose levels. The thiazolidinediones, also called glitazones, are insulin sensitisers that enable peripheral tissues to utilise insulin more effectively. The alpha-glucosidase inhibitors delay intestinal absorption of ingested carbohydrates. In addition to oral antidiabetic agents, insulin is frequently used in diabetes management. Insulin is always indicated in type 1 diabetes and is often necessary for residents with type 2 diabetes to optimise glycaemic control. Insulin can be rapid, fast, intermediate or long acting. In addition, basal insulin is now available. These insulins can be combined with each other and, in type 2 diabetes, with oral antidiabetic agents. In order to use pharmacological therapies appropriately, the glycaemic patterns of nursing home residents should be identified, using capillary blood glucose monitoring. Once these patterns have been identified, nonpharmacological therapies can be used, usually in conjunction with the many oral antidiabetic agents and various insulins available, to optimise glycaemic control in each resident.

Efficacy, dose-response relationship and safety of once-daily extended-release metformin (Glucophage XR) in type 2 diabetic patients with inadequate glycaemic control despite prior treatment with diet and exercise: results from two double-blind, placebo-controlled studies

AIM

The efficacy, dose-response relationships and safety of an extended-release formulation of metformin (Glucophage) XR) were evaluated in two double-blind, randomized, placebo-controlled studies of 24 and 16 weeks' duration, in patients with inadequate glycaemic control despite diet and exercise. Protocol 1 provided an evaluation of metformin XR at a commonly used dosage. Protocol 2 evaluated different dosages of metformin XR.

METHODS

In Protocol 1, 240 patients were randomized to receive metformin XR 1000 mg once daily. or placebo in a 2:1 ratio for 12 weeks (patients could receive metformin XR 1500 mg during weeks 12-24 if required). In Protocol 2, 742 patients were randomized to receive metformin XR 500 mg once daily, 1000 mg once daily, 1500 mg once daily, 2000 mg once daily, 1000 mg twice daily or placebo for 16 weeks. The primary endpoint in each study was the change from baseline in HbA(1C) at 12 weeks (Protocol 1) or 16 weeks (Protocol 2).

RESULTS

Metformin XR reduced HbA(1C) in Protocol 1, with mean treatment differences for 1000 mg once daily vs. placebo of -0.7% at 12 weeks and -0.8% at 24 weeks (p < 0.001 for each). In Protocol 2, a clear dose-response relationship was evident at doses up to 1500 mg, with treatment differences vs. placebo of -0.6% (500 mg once daily), -0.7% (1000 mg once daily), -1.0% (1500 mg once daily) and -1.0% (2000 mg once daily). The efficacy of metformin XR 2000 mg once daily and 1000 mg twice daily were similar (mean treatment differences vs. placebo in HbA(1C) were -1.0% and -1.2%, respectively). More patients achieved HbA(1C) < 7.0% with metformin XR vs. placebo in Protocol 1 (29% vs. 14% at 12 weeks) and with once-daily metformin XR in Protocol 2 (up to 36% vs. 10% at 16 weeks). No significant changes in fasting insulin or body weight occurred. Total and low-density lipoprotein (LDL)-cholesterol improved (p < 0.05-p < 0.001) in metformin XR groups in Protocol 2. Metformin XR was well tolerated; gastrointestinal side effects were more common with metformin XR vs. placebo, but few patients withdrew for this reason (1.3% vs. 1.3% in Protocol 1 and 1.6% vs. 0.9% in Protocol 2).

CONCLUSIONS

Once-daily metformin XR presents an effective and well-tolerated therapeutic option for delivering metformin in a convenient manner, which supports good compliance with therapy.

Strategies for managing the diabetic patient

Diabetes mellitus is now classified as either 'type 1' (failure of endogenous insulin production) or 'type 2' ('insulin resistance') and can be diagnosed if fasting blood glucose is >6.1 mmol/l (110mg/dl) on two separate occasions or there is unequivocal hyperglycaemia with acute metabolic decompensation or obvious symptoms. The prevalence of the disease is rising and may be as great as 12-14% in western populations aged over 40 years. Diabetes is complicated by micro- and macrovascular consequences of chronically elevated blood glucose concentrations, and diabetic patients are over-represented in hospital populations, particularly among patients requiring surgical interventions. It is associated with increased perioperative mortality and morbidity. Evidence is now accumulating that intensive glycaemic monitoring and the administration of insulin infusions to achieve tight glycaemic control are associated with an improvement of both perioperative mortality and morbidity.

Initiating oral glucose-lowering therapy with metformin in tyape 2 diabetic patients: an evidence-based strategy to reduce the burden of late-developing diabetes complications

A major aim of glucose-lowering therapy in people with diabetes is to delay or prevent the late-developing complications of diabetes that threaten the quality and duration of life. While intensive interventions to control hyperglycaemia may impair well-being to some extent, the balance of quality of life is usually highly positive. Diet and exercise therapy remains the cornerstone of management, and should usually be given a trial alone first. However, the magnitude and duration of benefit from this intervention is insufficient for most people. More frequent, early, use of metformin is an evidence-based strategy for reducing the risk of adverse outcomes of diabetes in people with type 2 diabetes with sub-optimal glucose control on lifestyle measures alone. This has been recognised in recent evidenced-based guidelines from the UK National Institute for Clinical Excellence and from Diabetes UK, which now support the use of metformin as initial pharmacological therapy for all people without contraindications to the drug. Other national and local guideline committees should consider updating their recommendations on diabetes management in line with these findings.

Achieving Glycemic Control in Type 2 Diabetes: A Practical Guide for Clinicians on Oral Hypoglycemics

Type 2 diabetes mellitus has reached epidemic proportions in the United States. Cardiovascular morbidity and mortality are particularly high in this patient population. Improved glucose control, especially early in the course of diabetes, can slow or prevent complications, preserve beta-cell function, and improve long-term outcomes. Within the last decade, new treatments and glycemic goals have created an opportunity to better manage this prevalent, chronic disease. Defects of insulin resistance and deficiency leading to type 2 diabetes can now be directly targeted with available therapies. In addition to diet and exercise, oral treatment options have been broadened, with both insulin secretagogues and insulin sensitizers. These advances in treatment options make glycemic control an obtainable target, and therefore should improve overall morbidity and mortality for patients. This paper will review currently available oral therapies, with a focus on the unique attributes of the insulin sensitizers for patients with type 2 diabetes.

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.

"Low dose" metformin improves hyperglycemia better than acarbose in type 2 diabetics

OBJECTIVES

"High dose" metformin therapy (2,550 mg/day) is reported to improve glycemic control in type 2 diabetic patients with obesity (body mass index (BMI) > or = 30). Some have reported that metformin therapy, even in low doses (500-750 mg/day), improves glycemic control in non-obese type 2 diabetic patients (BMI approximately 25). However, it is unclear whether "low dose" metformin improves glycemic control better than acarbose in non-obese type 2 diabetic patients, which has been shown to improve glycemic control in type 2 diabetes with obesity.

METHODS

We randomly divided 22 non-obese type 2 diabetic patients (mean BMI approximately 25) into two groups (A = 11, B = 11). Group A was treated with "low dose" metformin (500-750 mg/day) for 3 months, and switched to acarbose (150-300 mg/day) for another 3 months. Group B was treated with acarbose first, and then switched to "low dose" metformin.

RESULTS

"Low dose" metformin significantly decreased the fasting plasma glucose (FPG) and HbA1c level in both groups A and B, whereas acarbose decreased HbA1c levels in group B but not in group A. Overall, "low dose" metformin significantly decreased HbA1c (p=0.0165) levels as compared to acarbose.

CONCLUSION

In conclusion, "low dose" metformin therapy improved glycemic control better than acarbose in non-obese diabetics.

Metformin hydrochloride in the treatment of type 2 diabetes mellitus: a clinical review with a focus on dual therapy

BACKGROUND

Type 2 diabetes mellitus typically involves abnormal beta-cell function that results in relative insulin deficiency, insulin resistance accompanied by decreased glucose transport into muscle and fat cells, and increased hepatic glucose output, all of which contribute to hyperglycemia.

OBJECTIVE

This review examines the pharmacology, pharmacokinetics, drug-interaction potential, adverse effects, and dosing guidelines for metformin hydrochloride, a biguanide agent for the treatment of type 2 diabetes. Clinical trial data are reviewed, including efficacy and tolerability information, with a focus on studies of dual metformin therapy (metformin plus another oral agent or insulin) published from 1998 to the present. Pharmacoeconomic considerations are also discussed.

METHODS

Primary research and review articles were identified through a search of MEDLINE (1966-May 2003) and International Pharmaceutical Abstracts (1970-May 2003) using the terms metformin and/or Glucophage. Web of Science (1995-May 2003) was used to search for additional abstracts. The package inserts for metformin and metformin combination products were consulted. All identified articles and abstracts were assessed for relevance, and all relevant information was included. Priority was given to the primary medical literature and clinical trial reports.

RESULTS

Metformin is the only currently available oral antidiabetic/hypoglycemic agent that acts predominantly by inhibiting hepatic glucose release. Because patients with type 2 diabetes often have excess hepatic glucose output, use of metformin is effective in lowering glycosylated hemoglobin (HbA1c) by 1 to 2 percentage points when used as monotherapy or in combination with other blood glucose-lowering agents or insulin. Other metabolic variables (eg, dyslipidemia, fibrinolysis) may be improved with the use of metformin. Body weight is often maintained or slightly reduced from baseline. Metformin is well tolerated and is associated with few clinically deleterious adverse events. The most important and potentially life-threatening adverse event associated with its use is lactic acidosis, which occurs very rarely.

CONCLUSIONS

Metformin has multiple benefits in patients with type 2 diabetes. It can effectively lower HbA1c values, positively affect lipid profiles, and improve vascular and hemodynamic indices. Adverse effects are generally tolerable and self-limiting. The availability of products combining metformin with a sulfonylurea or rosiglitazone has expanded the array of therapies for the management of type 2 diabetes.

Comparison of pioglitazone and metformin efficacy using homeostasis model assessment

AIMS

To compare clinical efficacy of two different insulin sensitizers, pioglitazone and metformin, and to reveal factors that influence the clinical efficacy.

METHODS

Seventy-eight Japanese subjects with Type 2 diabetes mellitus poorly controlled with sulphonylureas [38 men and 40 women, aged 57 +/- 9 years, body mass index 25.2 +/- 1.4 kg/m2, and HbA1c 8.3 +/- 0.6% (means +/- SD)] were randomly assigned to groups for the addition of either pioglitazone or metformin and followed up for 4 months. A decrease in HbA1c levels was compared with baseline factors including homeostasis model assessment of insulin sensitivity (HOMA-R) and beta-cell function (HOMA-beta) with 71 subjects who completed the study.

RESULTS

The overall decrease in HbA1c levels was similar for the pioglitazone (-1.2 +/- 0.2%) and metformin (-1.3 +/- 0.1%) groups. In the pioglitazone group, the decrease in HbA1c levels was negatively correlated with baseline HOMA-R (r=-0.698, P<0.0001) and HOMA-beta (r=-0.680, P<0.0001). In contrast, the decrease was positively correlated with baseline HOMA-beta (r=0.556, P=0.0004) in the metformin group. Multivariate analysis revealed that either HOMA-R or HOMA-beta was a main determinant of the decrease in HbA1c levels in the pioglitazone group. In the metformin group, baseline levels of fasting glucose were also included as an independent determinant in addition to HOMA-beta. The subjects with greater HOMA-R (> or =4.0) or HOMA-beta (> or =40%) displayed better response to pioglitazone than to metformin, and vice versa.

CONCLUSIONS

In Type 2 diabetic subjects poorly controlled with sulphonylureas, addition of pioglitazone or metformin resulted in a comparable reduction in HbA1c levels. Subjects with greater insulin resistance or preserved beta-cell function displayed better response to pioglitazone, whereas subjects with reduced beta-cell function displayed better response to metformin.

Metformin: new understandings, new uses

Metformin, a biguanide, has been available in the US for the treatment of type 2 diabetes mellitus for nearly 8 years. Over this period of time, it has become the most widely prescribed antihyperglycaemic agent. Its mechanism of action involves the suppression of endogenous glucose production, primarily by the liver. Whether the drug actually has an insulin sensitising effect in peripheral tissues, such as muscle and fat, remains somewhat controversial. Nonetheless, because insulin levels decline with metformin use, it has been termed an 'insulin sensitiser'. Metformin has also been shown to have several beneficial effects on cardiovascular risk factors and it is the only oral antihyperglycaemic agent thus far associated with decreased macrovascular outcomes in patients with diabetes. Cardiovascular disease, impaired glucose tolerance and the polycystic ovary syndrome are now recognised as complications of the insulin resistance syndrome, and there is growing interest in the management of this extraordinarily common metabolic disorder. While diet and exercise remain the cornerstone of therapy for insulin resistance, pharmacological intervention is becoming an increasingly viable option. We review the role of metformin in the treatment of patients with type 2 diabetes and describe the additional benefits it provides over and above its effect on glucose levels alone. We also discuss its potential role for a variety of insulin resistant and prediabetic states, including impaired glucose tolerance, obesity, polycystic ovary syndrome and the metabolic abnormalities associated with HIV disease.

A Comparison of Agents Used to Manage Type 2 Diabetes Mellitus

In patients with type 2 diabetes mellitus, the traditional method of initiating therapy with a sulfonylurea and increasing the dosage until maximum levels are reached before adding an insulin-sensitizing agent has persisted and should be re-evaluated. Similarly, the current practice of starting therapy with one agent and increasing to maximum dosage before adding a second agent, rather than starting with combination therapy, also needs to be addressed. There is much evidence to suggest that initiating therapy with lower doses of two agents that have complementary effects can increase the overall efficacy and decrease the incidence of adverse effects. Clearly, there is a need for a paradigm shift away from the traditional approach of therapy using insulin secretagogues to a more pathophysiologic approach using an insulin-sensitizing agent, such as the thiazolidinediones. The thiazolidinediones have been shown to reduce insulin resistance, improve the ability of beta-cells to produce insulin, and decrease cardiac risk factors. By reducing insulin resistance, improving glycemic control, and preserving beta-cell function with a thiazolidinedione early in the course of therapy, it is likely that durable glycemic control will be achieved and both microvascular and macrovascular complications may be reduced. Furthermore, early use of an insulin-sensitizing agent either alone or incombination is expected to improve both acute and long-term outcomes in patients with type 2 diabetes.

Tolerability Profile of Metformin/Glibenclamide Combination Tablets (Glucovance??)

It is important to manage blood glucose intensively in patients with type 2 diabetes mellitus in order to reduce the risk of long-term complications. Oral combination therapy that addresses insulin resistance and beta-cell dysfunction is a proven means of improving glycaemic control when monotherapy becomes insufficiently effective. Metformin/glibenclamide (glyburide) combination tablets were developed to provide a means of applying this strategy while minimising polypharmacy. This review examines the tolerability profile of this treatment from four double-blind, randomised clinical trials in a total of 2342 type 2 diabetic patients with hyperglycaemia despite treatment with diet and exercise, a sulphonylurea or metformin. Treatment with combination tablets was associated with markedly superior blood glucose control, at lower doses of metformin and glibenclamide, compared with monotherapies. The incidence of symptoms of hypoglycaemia varied between dosages and trials, though the incidence of severe or biochemically confirmed hypoglycaemia or withdrawals from clinical trials for this reason was consistently low and comparable with glibenclamide alone. No patient required third-party assistance for hypoglycaemia. Significantly fewer diet-failed patients receiving low-dose combination tablets reported gastrointestinal adverse effects compared with metformin alone, with a comparable incidence between metformin and combination tablets in post-monotherapy studies. The incidence of other adverse events, including serious adverse events, was similar for combination tablets and monotherapies. The lower doses of metformin and glibenclamide with the combination tablet approach, and the design of the combination tablets themselves, may underlie the beneficial tolerability profile of this treatment.

Nine weeks of bedtime diazoxide is well tolerated and improves beta-cell function in subjects with Type 2 diabetes

AIMS

To test whether a bedtime dose of diazoxide can improve daytime beta-cell function without side-effects in Type 2 diabetes.

METHODS

A double-blind randomized study was performed in 27 Type 2 diabetic subjects (17 male, 10 female) who were treated with bedtime insulin and metformin. Subjects received either bedtime diazoxide, 100 mg, or placebo for 9 weeks. Duplicate C-peptide glucagon tests were performed before and in the last days of intervention.

RESULTS

No side-effects of diazoxide were detected. Treatment with diazoxide did not incur any increase in bedtime insulin. C-peptide responses to glucagon tended to increase: 0.15 +/- 0.06 nmol/l vs. -0.01 +/- 0.04 nmol/l for placebo, P < 0.06 for difference. Corresponding effects on insulin were 66.2 +/- 41.7 pmol/l for diazoxide vs. -84.2 +/- 51.5 for placebo, P < 0.03. Treatment with diazoxide decreased fasting glucagon levels by 41% vs. placebo, P < 0.03. Glycated haemoglobin (HbA1c) levels were not affected, whereas levels of blood glucose post breakfast were higher during diazoxide (1.34 +/- 0.43 mmol/l, P < 0.01 vs. placebo).

CONCLUSIONS

Bedtime treatment with diazoxide in Type 2 diabetic subjects on bedtime insulin and metformin has no significant side-effects, does not increase bedtime insulin supplementation, tends to ameliorate beta-cell function but fails to improve metabolic control.

The role of metformin in the management of polycystic ovary syndrome

PURPOSE OF REVIEW

The purpose of this review is to provide a critical summary of recent studies on the clinical effects of metformin in polycystic ovary syndrome.

RECENT FINDINGS

After the recognition that hyperinsulinaemia is a fundamental disturbance in polycystic ovary syndrome, a novel and promising form of therapy in the form of insulin-sensitizing drugs has been introduced. Among these, metformin is the most widely used. This therapeutic intervention has been shown to exert beneficial effects on the endocrine and metabolic disturbances that characterize the syndrome and, more recently, to improve the reproductive outcome in women with polycystic ovary syndrome. With rapid progress in this area, metformin use has also been extended to the management of lean polycystic ovary syndrome patients.

SUMMARY

Although most studies are nonrandomized trials, current data provide a rationale for metformin as first-line management for women with polycystic ovary syndrome, alone or in combination with conventional treatments. Controversy still exists, however, regarding the mechanisms by which metformin exerts its beneficial effects in polycystic ovary syndrome.

Quantitative insulin sensitivity check index and the reciprocal index of homeostasis model assessment in normal range weight and moderately obese type 2 diabetic patients

OBJECTIVE

To investigate whether the quantitative insulin sensitivity check index (QUICKI) and the reciprocal index of homeostasis model assessment (1/HOMA-IR) derived from fasting plasma glucose and insulin level are excellent surrogate indices of insulin resistance in both normal range-weight and moderately obese type 2 diabetic and healthy subjects.

RESEARCH DESIGN AND METHODS

The association between QUICKI or 1/HOMA-IR and insulin resistance index assessed by euglycemic-hyperinsulinemic clamp (clamp-IR) was investigated in 121 type 2 diabetic and 29 healthy subjects recruited from among 120 (age 55 +/- 11, 48 +/- 15, and 52 +/- 15 years [means +/- SD], respectively). Type 2 diabetic subjects were divided into groups of 76 normal range-weight and 45 moderately obese subjects (BMI 21.4 +/- 2.3 vs. 27.2 +/- 2.2 kg/m(2), P < 0.0001).

RESULTS

QUICKI and 1/HOMA-IR were significantly lower in the moderately obese group than in the normal range-weight type 2 diabetic and healthy groups (n = 120) (QUICKI, 0.338 +/- 0.030, 0.371 +/- 0.037, and 0.389 +/- 0.041, respectively, P < 0.0001; 1/HOMA-IR, 0.50 +/- 0.33, 0.92 +/- 0.55, and 1.24 +/- 0.82, P < 0.0001). QUICKI was strongly correlated with clamp-IR in normal range-weight, moderately obese type 2 diabetic, and healthy subjects (r = 0.641, 0.570, and 0.502, respectively; all subjects, r = 0.608, P < 0.01) and 1/HOMA-IR exhibited correlations comparable to those of QUICKI with clamp-IR (r = 0.637, 0.530, and 0.461, respectively; all subjects, r = 0.589, P < 0.001). In multiple regression models including QUICKI or 1/HOMA-IR as an independent variable, the estimation formula accounted for 55% of the variability of clamp-IR for the group of all type 2 diabetic subjects (R(2) = 0.547 and 0.551, respectively, P <or= 0.0001).

CONCLUSIONS

QUICKI and 1/HOMA-IR were highly correlated with clamp-IR, with comparable coefficients in both normal range-weight and moderately obese type 2 diabetic patients and nondiabetic subjects. The latter can probably be applied clinically in view of its convenience.

Drug therapy of diabetes in the elderly

The prevalence of type 2 diabetes mellitus is increasing in the elderly. Although type 1 diabetic patients are living longer, over 95% of elderly people affected with diabetes have type 2 diabetes. This segment of the population, comprising men and women older than 65 years of age, is more likely to develop coexisting illnesses predisposing to the development of diabetes and complicating its management. In addition to changes in lifestyle, inherent age-related changes in carbohydrate metabolism contribute to the development of type 2 diabetes in old age. The long-term outcome of tight blood sugar control in the elderly is not known. Nevertheless the principles of management of type 2 diabetes in the elderly are essentially the same as in young- or middle-aged diabetic patients. Lifestyle modifications remain the cornerstone of medical therapy. When diet and exercise fail to achieve proper glycemic control, oral pharmacologic therapy and/or insulin therapy is indicated. The recently available oral glucose lowering agents in the market along with the newer types of insulin can be used in elderly diabetic patients. The effect of aging on metabolism and drug elimination kinetics must, however, be taken into consideration. In particular, it should be borne in mind that the risk of hypoglycemia is more deleterious in the elderly and should be avoided. In this review, the various pharmacologic agents available for the management of diabetes will be reviewed and some pertinent clinical guidelines will be suggested.

Current therapeutic options in type 2 diabetes mellitus: a practical approach

The incidence of type 2 diabetes mellitus (DM) in the United States continues to grow rapidly, paralleling the overweight and obesity epidemic. For many years the only therapeutic options for type 2 DM were sulfonylureas and insulin. However, over the last 9 years there has been an explosion of new and exciting agents approved for the treatment of type 2 DM. Some of the treatments target insulin deficiency and others insulin resistance, the hallmarks of the disease. Other drugs delay the intestinal absorption of carbohydrate. Recently several combination agents have been released. With these new drugs has come an overwhelming mountain of information, making it difficult for the busy clinician to know how best to manage the ever-increasing portion of patients with type 2 DM. New questions have arisen: Which agent to start as first line? How much of this drug to use before adding something else? How long for this drug to reach full effect? Which agent to add second? Should a patient uncontrolled on dual therapy begin insulin or start a third oral agent? If insulin therapy is started, what should become of the patient's oral agents? How best to explain the patient's weight gain on therapy? These are not easy questions and no review can fully detail all the therapeutic combinations possible. Instead, the practical approach of reviewing the agents in terms of their mechanism of action and critically comparing their dosing, effect and cost, is undertaken herein. Also addressed is the possible niche some newer classes of agents and combination drugs may or may not hold in the management of type 2 DM. The decision of using insulin versus a third oral agent will be looked at from the standpoint of where the patient is on dual therapy in relation to the hemoglobin A1c goal. In this way it is hoped that some clarity will be brought to the dizzying array of information that both the physician and patient have to deal with in regard to the management of this prevalent and serious disease.