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PubMedDate not supplied

Cardioprotection with pioglitazone is abolished by nitric oxide synthase inhibitor in ischemic rabbit hearts--comparison of the effects of pioglitazone and metformin.

BACKGROUND: The effects of two drugs representing different classes of antidiabetic pharmacology (pioglitazone, a thiazolidinedione; and metformin, a biguanide) on the myocardial metabolism in the ischemia are poorly understood. METHODS: To test the hypothesis that cardioprotection of pioglitazone and metformin is associated with nitric oxide (NO), we studied the high energy phosphate metabolism by 31P-nuclear magnetic resonance (NMR) in isolated rabbit hearts. Forty-five minutes of continuous normothermic global ischemia was carried out. Pioglitazone or metformin was administered at the beginning, 60 min prior to the global ischemia, with or without the nitric oxide synthase inhibitor, L-NAME, administered 5 min or 60 min prior to the ischemia. In the first experiment, whether NO was produced or not by administration of pioglitazone, for the prevention of myocardial ischemic injury, was investigated. Hearts of male Japanese white rabbits were divided into 4 experimental groups: the control (C) group, the P group consisting of pioglitazone treatment, the P + L5 group consisting of pioglitazone treatment with L-NAME (5 min before ischemia), and the P + L60 group consisting of pioglitazone treatment with L-NAME (60 min before ischemia). In the next experiment, a comparison between the effects of pioglitazone and metformin in preventing ischemic injury were studied. The hearts were divided into 4 experimental groups: the control (C) group, the P group consisting of pioglitazone treatment, the P + L5 group consisting of pioglitazone treatment with L-NAME (5 min before ischemia), the M group consisting of metformin treatment, and the M + L5 group consisting of metformin treatment with L-NAME (5 min before ischemia). RESULTS: In the first experiment, the decrease in adenosine triphosphate (ATP) during ischemia was significantly inhibited in the P group in comparison with the C group (P < 0.01). However, the decrease in ATP was not inhibited in the P + L5 group during ischemia. In contrast, in the P + L60 group, the decrease in ATP was not inhibited during a part of ischemia. In the next experiment, a comparison between the effects of pioglitazone and metformin in preventing ischemic injury was studied. As a result of administration of either pioglitazone or metformin, there was no difference between groups with and without L-NAME. CONCLUSION: These results suggest that pioglitazone has a significant beneficial effect on improving the myocardial energy metabolism during ischemia. This cardioprotection may be dependent on nitric oxide (NO) synthase during ischemia more than preischemia. Furthermore, the present findings suggest that both pioglitazone and metformin have equal cardioprotective effects mediated by NO on myocardial ischemic injury in rabbits.

Adenosine Triphosphate↗
PubMed2005

Long-term effects on lipids and lipoproteins of pioglitazone versus gliclazide addition to metformin and pioglitazone versus metformin addition to sulphonylurea in the treatment of type 2 diabetes.

AIMS/HYPOTHESIS: The aim of this study was to determine the long-term effects of pioglitazone add-on to metformin or sulphonylurea on plasma lipids and lipoproteins. MATERIALS AND METHODS: The effects of pioglitazone were studied in two clinical trials in patients with inadequately controlled type 2 diabetes (HbA1c > or =7.5 and < or =11%). In the first trial, patients currently receiving metformin were randomised to pioglitazone (15-45 mg/day, n=317) or gliclazide (80-320 mg/day, n=313) add-on therapy. In the second study, pioglitazone (15-45 mg/day, n=319) or metformin (850-2,550 mg/day, n=320) was added to sulphonylurea therapy. Patients were force-titrated to the maximum tolerated dose of add-on therapy, which was maintained to the 2-year endpoint. RESULTS: There were no statistically significant differences between the groups with respect to HbA1c reduction from baseline to week 104. Whether added to metformin or sulphonylurea, pioglitazone caused highly significant greater decreases in triglycerides and increases in HDL cholesterol from baseline to week 104 than treatments with gliclazide or metformin add-on therapies (p< or =0.001). The triglyceride reductions noted with pioglitazone were maintained over time, with decreases of 16-18% at 1 year and 17-23% at 2 years. In the pioglitazone groups, the improvement in HDL cholesterol at 1 year was maintained, with 21-22% augmentations at 2 years (p<0.001 between-group difference). Small but statistically significant greater reductions in LDL cholesterol were observed with gliclazide vs pioglitazone add-on to metformin and metformin vs pioglitazone add-on to sulphonylurea (p<0.001 for between-group difference). In the pioglitazone groups, mean LDL cholesterol at 2 years was similar to mean baseline LDL cholesterol. CONCLUSIONS/INTERPRETATION: After 2 years, highly significant decreases in triglycerides and increases in HDL cholesterol that were sustained over time or even improved were observed when pioglitazone was added to metformin or sulphonylurea therapy. These effects of pioglitazone on lipids may be potentially beneficial in reducing cardiovascular risk in type 2 diabetes.

Adult↗
PubMed2000

Pioglitazone hydrochloride in combination with metformin in the treatment of type 2 diabetes mellitus: a randomized, placebo-controlled study. The Pioglitazone 027 Study Group.

BACKGROUND: Their complimentary mechanisms of action suggest that a combination of pioglitazone hydrochloride and metformin may have clinically beneficial effects in the treatment of patients with type 2 diabetes. OBJECTIVE: This study was undertaken to assess the efficacy and tolerability of pioglitazone in combination with metformin in patients with type 2 diabetes mellitus. METHODS: This was a 16-week, double-blind study with the option of enrollment in a separate open-ended, open-label study. It included patients with poorly controlled diabetes mellitus (glycated hemoglobin [HbA1c] > or =8.0%, fasting C-peptide >1.0 ng/mL) who had been receiving a stable regimen of metformin for > or =30 days. Patients with diabetic retinopathy, nephropathy, or neuropathy; impaired liver or kidney function; or unstable cardiovascular or cerebrovascular conditions were excluded. Patients were randomized to receive once-daily pioglitazone 30 mg + metformin or placebo + metformin. Patients in the open-label extension received pioglitazone 30 mg (with optional titration to 45 mg) + metformin. RESULTS: Three hundred twenty-eight patients were randomized to treatment (168 pioglitazone + metformin, 160 placebo + metformin), and 249 completed the study. Of these, 154 elected to enter the open-label extension study. Patients' mean age was 56 years; most (84%) were white and slightly more than half (57%) were male. Patients receiving piogli- tazone 30 mg + metformin had statistically significant mean decreases in HbA1c (-0.83%) and fasting plasma glucose (FPG) levels (-37.7 mg/dL) compared with placebo + metformin (P < or = 0.05). Decreases in FPG levels occurred as early as the fourth week of therapy, the first time point at which FPG was measured. The pioglitazone + metformin group had significant mean percentage changes in levels of triglycerides (-18.2%) and high-density lipoprotein cholesterol (+8.7%) compared with placebo + metformin (P < or = 0.05). Mean percentage increases were noted in low-density lipoprotein cholesterol levels (7.7%, pioglitazone + metformin; 11.9%, placebo + metformin) and total cholesterol (4.1%, pioglitazone + metformin; 1.1%, placebo + metformin), with no significant differences between groups. In the extension study, patients treated with open-label pioglitazone + metformin for 72 weeks had mean changes from baseline of -1.36% in HbA1c and -63.0 mg/dL in FPG. The incidence of adverse events was similar in both groups. Throughout the study, no patient in either treatment group had an alanine aminotransferase (ALT) value > or =3 times the upper limit of normal, a commonly used marker of potential liver damage. Thus, no evidence of drug-induced hepatotoxicity or drug-induced elevations in serum ALT was observed. CONCLUSIONS: In this study in patients with type 2 diabetes mellitus, pioglitazone + metformin significantly improved HbA1c and FPG levels, with positive effects on serum lipid levels and no evidence of drug-induced hepatotoxicity. These effects were maintained for >1.5 years, including the open-label extension.

Adult↗
PubMed2005

Comparison of pioglitazone with other antidiabetic drugs for associated incidence of liver failure: no evidence of increased risk of liver failure with pioglitazone.

AIM: The aim of this study was to assess the incidence of liver failure in association with antidiabetic treatment using pioglitazone vs. other oral antidiabetic medications. METHODS: The study was a retrospective analysis of claim data from the PharMetrics Patient-Centric Database that had over 1.12 million enrollees with type 2 diabetes. All patients, > or =18 years of age with type 2 diabetes, who had initiated treatment either with a thiazolidinedione (pioglitazone and rosiglitazone), sulfonylurea or metformin were identified and matched on the basis of propensity scores, which served as a proxy for severity of disease. The primary measure of interest was the incidence of liver failure or hepatitis post-index date. In addition to unadjusted comparisons, Cox proportional hazard models were employed to estimate the risk of developing liver failure or hepatitis. RESULTS: There was no significant difference in the 1- and 2-year incidence rates of liver failure or hepatitis (primary and secondary diagnoses) between the pioglitazone monotherapy group and the respective comparator groups. In Cox proportional hazard models controlling for age, pre-index total healthcare costs, Charlson comorbidity index, procedures and a hospitalization or Emergency room (ER) visit for pre-index hyperglycaemia, and pioglitazone were not associated with an increased risk of liver failure or hepatitis, compared to all other defined groups. Furthermore, no primary or secondary diagnosis of liver failure was reported in the pioglitazone group during the follow-up period. CONCLUSIONS: Results of retrospective data analysis demonstrate no evidence of increased risk of liver failure or hepatitis for patients initiating therapy on pioglitazone, compared to other oral antidiabetic agents. Pioglitazone therapy was not associated with an increased risk of liver failure at 2 years relative to other oral antidiabetic therapies.

Administration, Oral↗
PubMed2006

Safety and efficacy of low-dose pioglitazone (7.5 mg/day) vs. standard-dose pioglitazone (15 mg/day) in Japanese women with type 2 diabetes mellitus.

It is well known that pioglitazone, a potent thiazolidinedione, improves metabolic control. However, weight gain or peripheral edema may be of major clinical concern when using this agent. The purpose of our study was to prospectively evaluate the effects of low-dose pioglitazone (7.5 mg/day) on metabolic control, weight gain and the incidence of edema compared with a standard dose of pioglitazone (15.0 mg/day) in patients with type 2 diabetes mellitus (T2DM). Ninety-five Japanese female patients (mean age 58.4 +/- 10.4 years) with newly diagnosed T2DM were selected for this study. They were randomly divided into the following 2 groups according to therapy regimens, and examined every month for 6 months after diagnosis. Group A consisted of 54 patients treated with low-dose pioglitazone orally; Group B, the control-group, consisted of 41 patients treated with standard-dose pioglitazone orally. The incidence of peripheral edema was significantly much lower in group A (2/54) than in group B (11/41) (p = 0.0014). In addition, % change of body weight during the 6-month treatment in group A was significantly less than that in group B (p < 0.0001). On the other hand, the % change of biochemical parameters including HbA1c did not differ significantly between group A and group B, although glucose and lipid control significantly improved from baseline in both groups. Our results demonstrate the safety and efficacy of low-dose pioglitazone, suggesting that it could be another good choice of treatment for Japanese women with T2DM.

Administration, Oral↗
PubMed2000

Pioglitazone hydrochloride monotherapy improves glycemic control in the treatment of patients with type 2 diabetes: a 6-month randomized placebo-controlled dose-response study. The Pioglitazone 001 Study Group.

OBJECTIVE: To evaluate the efficacy and safety of four doses of pioglitazone monotherapy in the treatment of patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: There were 408 patients randomized in this multicenter double-blind placebo-controlled clinical trial. Patients who had HbA1c > or = 7.0%, fasting plasma glucose (FPG) > or = 140 mg/dl, and C-peptide > 1 ng/ml were randomized to receive placebo or 7.5, 15, 30, or 45 mg pioglitazone administered once a day for 26 weeks. RESULTS: Patients treated with 15, 30, or 45 mg pioglitazone had significant mean decreases in HbA1c (range -1.00 to -1.60% difference from placebo) and FPG (-39.1 to -65.3 mg/dl difference from placebo). The decreases in FPG were observed as early as the second week of therapy; maximal decreases occurred after 10-14 weeks and were maintained until the end of therapy (week 26). In the 15-, 30-, or 45-mg pioglitazone groups, there were significant mean percent decreases in triglycerides, significant mean percent increases in HDL cholesterol, and only small percent changes in total cholesterol and LDL. The subset of patients naive to therapy had greater improvements in HbA1c and FPG (difference from placebo of -2.55% and -79.9 mg/dl for the 45-mg group) compared with previously treated patients. The overall adverse event profile of pioglitazone was similar to that of placebo. There was no evidence of drug-induced hepatotoxicity or drug-induced elevations of alanine aminotransferase levels in this study CONCLUSIONS: Pioglitazone monotherapy significantly improves HbA1c and FPG while producing beneficial effects on serum lipids in patients with type 2 diabetes with no evidence of drug-induced hepatotoxicity.

Adult↗
PubMed2004

The prospective pioglitazone clinical trial in macrovascular events (PROactive): can pioglitazone reduce cardiovascular events in diabetes? Study design and baseline characteristics of 5238 patients.

OBJECTIVE: The PROspective pioglitAzone Clinical Trial In macroVascular Events (PROactive) assesses the effect of pioglitazone, a peroxisome proliferator-activated receptor agonist, with anti-inflammatory and vascular properties, on the secondary prevention of macrovascular events in type 2 diabetes. RESEARCH DESIGN AND METHODS: PROactive is an on-going randomized, double-blind outcome study in patients with type 2 diabetes managed with diet and/or oral blood glucose-lowering drugs (combination of oral agents with insulin is permitted) who have a history of macrovascular disease. Patients are randomized to receive pioglitazone (forced titration from 15 to 30 to 45 mg, depending on tolerability) or placebo in addition to existing therapy. The primary end point is the time from randomization to occurrence of a new macrovascular event or death. Follow-up is estimated to span 4 years. RESULTS: A total of 5238 patients have been randomized from 19 countries. At entry into the study, patients enrolled are a mean age of 61.8 years, with type 2 diabetes for a mean of 9.5 years; 60.9 and 61.5% are taking metformin or a sulfonylurea, respectively; and 33.6% are using insulin in addition to oral glucose-lowering drugs. The majority of patients are men (66.1%). Patients are required to meet one or more of entry criteria, as follows: >6 months' history of myocardial infarction (46.7%); coronary artery revascularization (30.8%), stroke (18.8%), or acute coronary syndrome for >3 months (13.7%); other evidence of coronary artery disease (48.1%); or peripheral arterial occlusive disease (19.9%). One-half (48.5%) of the patients have two or more of these risk factors. Three-quarters (75.4%) have hypertension, and 58.8% are current or previous smokers. CONCLUSIONS: The cohort of patients enrolled in PROactive is a typical type 2 diabetic population at high risk of further macrovascular events. The characteristics of this population are ideal for assessing the ability of pioglitazone to reduce the cardiovascular risk of patients with type 2 diabetes.

Adult↗
PubMed2005

Effects of gemfibrozil, itraconazole, and their combination on the pharmacokinetics of pioglitazone.

BACKGROUND AND OBJECTIVE: The thiazolidinedione antidiabetic drug pioglitazone is metabolized mainly by cytochrome P450 (CYP) 2C8 and CYP3A4 in vitro. Our objective was to study the effects of gemfibrozil, itraconazole, and their combination on the pharmacokinetics of pioglitazone to determine the role of these enzymes in the fate of pioglitazone in humans. METHODS: In a randomized, double-blind, 4-phase crossover study, 12 healthy volunteers took either 600 mg gemfibrozil or 100 mg itraconazole (first dose, 200 mg), both gemfibrozil and itraconazole, or placebo twice daily for 4 days. On day 3, they received a single dose of 15 mg pioglitazone. Plasma drug concentrations and the cumulative excretion of pioglitazone and its metabolites into urine were measured for up to 48 hours. RESULTS: Gemfibrozil alone raised the mean total area under the plasma concentration-time curve from time 0 to infinity [AUC(0-infinity)] of pioglitazone 3.2-fold (range, 2.3-fold to 6.5-fold; P < .001) and prolonged its elimination half-life (t (1/2) ) from 8.3 to 22.7 hours ( P < .001) but had no significant effect on its peak concentration (C max ) compared with placebo (control). Gemfibrozil increased the 48-hour excretion of pioglitazone into urine by 2.5-fold ( P < .001) and reduced the ratios of the active metabolites M-III and M-IV to pioglitazone in plasma and urine. Gemfibrozil decreased the area under the plasma concentration-time curve from time 0 to 48 hours [AUC(0-48)] of the metabolites M-III and M-IV by 42% ( P < .05) and 45% ( P < .001), respectively, but their total AUC(0-infinity) values were reduced by less or not at all. Itraconazole had no significant effect on the pharmacokinetics of pioglitazone and did not alter the effect of gemfibrozil on pioglitazone pharmacokinetics. The mean area under the concentration versus time curve to 49 hours [AUC(0-49)] of itraconazole was 46% lower ( P < .001) during the gemfibrozil-itraconazole phase than during the itraconazole phase. CONCLUSIONS: Gemfibrozil elevates the plasma concentrations of pioglitazone, probably by inhibition of its CYP2C8-mediated metabolism. CYP2C8 appears to be of major importance and CYP3A4 of minor importance in pioglitazone metabolism in vivo in humans. Concomitant use of gemfibrozil with pioglitazone may increase the effects and risk of dose-related adverse effects of pioglitazone. However, studies in diabetic patients are needed to determine the clinical significance of the gemfibrozil-pioglitazone interaction.

Administration, Oral↗
PubMed2005

Pioglitazone, a PPARgamma agonist, restores endothelial function in aorta of streptozotocin-induced diabetic rats.

OBJECTIVE: To study the effect of pioglitazone (a PPAR gamma agonist) treatment on blood pressure, endothelial function, and oxidative stress in streptozotocin (STZ)-induced diabetic rats. METHODS: Sprague-Dawley rats were randomized into control (n=32) and STZ-diabetic (n=32) groups. Rats were further randomized to receive pioglitazone (10 mg/kg) or placebo for 4 weeks, and the following protocols were carried out. Blood pressure, blood glucose level, and body weight were measured. Thoracic aorta was isolated and the dose-response curve of phenylephrine (PE) in the presence or absence of Nomega-nitro-L-arginine-methyl ester (L-NAME) was recorded. The dose-response curve of acetylcholine (Ach) in the presence or absence of indomethacin, L-NAME, and methylene blue was recorded. Tone-related basal nitric oxide release experiments were carried out. Lipid peroxidation, superoxide dismutase, catalase, and reduced glutathione were estimated in liver, kidney, and aorta. Aortic nitrite levels were also measured. Further, in vitro effects of PE and Ach in the presence of pioglitazone (0.1 M-10 mM) were measured in aortic rings of nondiabetic and STZ-diabetic rats. Pioglitazone-induced relaxations were recorded in PE-contracted rings (with intact and denuded endothelium) in the presence of L-NAME and in KCl-contracted rings. RESULTS: Pioglitazone treatment reduced blood pressure without having any significant effect on blood glucose level and body weight of STZ-diabetic rats. Enhanced PE-induced contraction and impaired Ach-induced relaxations in STZ-diabetic rats were restored to normal by pioglitazone treatment. The presence of L-NAME but not indomethacin blocked Ach-induced relaxation in pioglitazone-treated STZ-diabetic rats. Basal nitric oxide release was significantly higher in pioglitazone-treated STZ-diabetic rats. Oxidative stress was significantly higher in STZ-diabetic rats and pioglitazone treatment significantly reduced it. High aortic nitrite levels of STZ-diabetic rats were significantly reduced by pioglitazone treatment. The presence of pioglitazone at higher concentrations (>10 muM), but not at lower concentrations, significantly changed the dose-response curve of PE or Ach. Pioglitazone relaxations at lower concentrations but not at higher concentrations were blocked by endothelium removal or by the presence of L-NAME. CONCLUSION: Pioglitazone administration reduced oxidative stress, which prevented the breakdown of nitric oxide and increased nitric oxide levels, thereby restoring the endothelial function in aorta of STZ-diabetic rat. Hence, from the present study it can be concluded that pioglitazone administration in STZ-diabetic rats lowers blood pressure, protects against oxidative stress, and restores endothelial function.

Acetylcholine↗
PubMed2005

Efficacy and safety of biphasic insulin aspart 30 combined with pioglitazone in type 2 diabetes poorly controlled on glibenclamide (glyburide) monotherapy or combination therapy: an 18-week, randomized, open-label study.

BACKGROUND: Few large randomized controlled trials have assessed the value of adding insulin to an oral antidiabetic drug regimen. OBJECTIVE: This trial compared the efficacy and safety of biphasic insulin aspart 30/70 (BIAsp 30) plus pioglitazone (n = 93), glibenclamide (glyburide) plus pioglitazone (n = 91), or BIAsp 30 monotherapy (n = 97). METHODS: This 18-week, multinational, multicenter, randomized, open-label, parallel-group trial involved 281 patients with type 2 diabetes (60% male; mean age, 56 years; mean body mass index, 29.5 kg/m2) with inadequate glycemic control (mean glycosylated hemoglobin [HbA(1c)], 9.5%; range, 7.4%-14.7%) on glibenclamide monotherapy or combination therapy. The primary objective was to compare end-of-trial HbA(1c) among the 3 treatment groups. Fasting and mean 7- and 8-point blood glucose profiles, blood lipid levels, plasminogen activator inhibitor levels, adverse events, and hypoglycemia frequency were also compared. Patients using BIAsp 30 (alone or with pioglitazone) were injected twice daily (immediately before breakfast and dinner). Pioglitazone (30 mg/d) and glibenclamide (5-15 mg/d) were taken orally once daily with or immediately after breakfast. RESULTS: At the end of the trial, HbA(1c) was significantly lower for the BIAsp 30 plus pioglitazone group than for the glibenclamide plus pioglitazone group (mean [SD], -0.64% [0.23%]; P = 0.005) and the BIAsp 30 monotherapy group (-0.60% [0.22%]; P = 0.008). Mean (SD) fasting blood glucose (before breakfast) was significantly lower for BIAsp 30 plus pioglitazone than for glibenclamide plus pioglitazone (153 [45] mg/dL vs 169 [65] mg/dL, respectively; P = 0.012). Each time point on the 8-point blood glucose profile was lower for BIAsp 30 plus pioglitazone than for glibenclamide plus pioglitazone (P < 0.001 to P < 0.05). No major hypoglycemic episodes were reported, and the absolute rate of hypoglycemic events was low (<1 event/patient-week) in the BIAsp-only group. Edema was reported in < or =9% of patients in each treatment group, but no occurrence was classified as serious. Weight gain (mean, 4.0 kg) was more common in the BIAsp plus pioglitazone group (8%); however, this was consistent with improved glycemic control and is similar to that reported in other pioglitazone trials. CONCLUSIONS: BIAsp 30 plus pioglitazone provided an efficacious and well-tolerated treatment alternative to glibenclamide plus pioglitazone or BIAsp 30 alone in this population of patients who previously were not well controlled on glibenclamide monotherapy or combination therapy.

Blood Glucose↗
PubMed2004

Effects of pioglitazone and glimepiride on glycemic control and insulin sensitivity in Mexican patients with type 2 diabetes mellitus: A multicenter, randomized, double-blind, parallel-group trial.

BACKGROUND: Pioglitazone and glimepiride improve glycemic control in patients with type 2 diabetes mellitus by different mechanisms. Pioglitazone is a thiazolidinedione that reduces insulin resistance, and glimepiride is a sulfonylurea insulin secretagogue. OBJECTIVE: The goals of this study were to compare changes in measures of glycemic control and insulin sensitivity in Mexican patients with type 2 diabetes who received pioglitazone or glimepiride for 1 year. METHODS: This was a multicenter, 52-week, double-blind, parallel-group trial. Patients were randomized to receive monotherapy with either glimepiride (2 mg QD initially) or pioglitazone (15 mg QD initially). Doses were titrated (maximal doses: pioglitazone 45 mg, glimepiride 8 mg) to achieve glycemic targets (fasting blood glucose < or =7 mmol/L and 1-hour postprandial blood glucose < or =10 mmol/L). Insulin sensitivity (primary end point) was evaluated in terms of the Homeostasis Model Assessment for Insulin Sensitivity (HOMA-S), the Quantitative Insulin Sensitivity Check Index (QUICKI), and fasting serum insulin (FSI) concentrations. Glycemic control was evaluated in terms of glycosylated hemoglobin (HbA(1c)) values and fasting plasma glucose (FPG) concentrations. Patients were encouraged to maintain their individual diet and exercise regimens throughout the study. RESULTS: Two hundred forty-four patients (125 women, 119 men; all but 1 Hispanic) were randomized to receive pioglitazone (n = 121) or glimepiride (n = 123). In the intent-to-treat sample, pioglitazone and glimepirede produced comparable reductions in HbA(1c) from baseline to the end of the study (-0.78% and -0.68%, respectively). The pioglitazone group had significantly higher HbA(1c) values compared with the glimepiride group after 12 weeks of therapy (8.66% vs 7.80%; P = 0.007) but had significantly lower values after 52 weeks (7.46% vs 7.77%; P = 0.027). Pioglitazone significantly reduced FPG compared with glimepiride (-0.6 vs 0.6 mmol/L; P = 0.01). Pioglitazone therapy was associated with significant increases in insulin sensitivity (reduced insulin resistance), whereas glimepiride had no effect. HOMA-S values changed 18.0% for pioglitazone and -7.9% for glimepiride (P < 0.001), QUICKI values changed a respective 0.013 and -0.007 (P < 0.001), and FSI values were -21.1 and 15.1 pmol/L (P< 0.001). Both drugs were well tolerated, with pioglitazone associated with more peripheral edema (number of treatment-emergent cases: 35/121[28.9%] vs 17/123 [13.8%]; P = 0.005) and fewer hypoglycemic episodes (19 [15.7%] vs 38 [30.9%]; P = 0.024). The incidence of weight gain was not significantly different between treatment groups. CONCLUSIONS: These data suggest that long-term treatment with pioglitazone enhances insulin sensitivity relative to glimepiride in Mexican patients with type 2 diabetes and that pioglitazone may have a more sustained antihyperglycemic effect.

Blood Glucose↗
PubMed2005

Pioglitazone mimics preconditioning in the isolated perfused rat heart: a role for the prosurvival kinases PI3K and P42/44MAPK.

Ischemic preconditioning, the most powerful protection against infarction, activates PI3Kinase (PI3K)/AKT and P42/44MAPK. Pioglitazone, a thiazolidinedione and PPARgamma receptor agonist used in Type II diabetes treatment, has been shown to activate these kinase cascades. We therefore hypothesized that pioglitazone could protect the myocardium when given prior to myocardial ischemia/reperfusion injury. Langendorff perfused rat hearts underwent 40 minutes of stabilization then 35 minutes of regional ischemia and 120 minutes of reperfusion (control) or Pioglitazone (1, 2, 5, and 10 microM)-given before ischemia. Additional groups underwent the same protocol but with either PI3K inhibitors (15 microM LY294002 or 100 nM wortmannin) or P42/44MAPK inhibitors (10 microM U0126 or 10 microM PD98059) given either during stabilization or at reperfusion. Infarct size was determined as a percentage of risk zone (I/R%). Pioglitazone (2 microM) significantly reduced I/R% compared with control (25.4 +/- 3.1 versus 47.3 +/- 3.4; P < 0.05). This protection was abolished by PI3K inhibitors (pioglitazone+LY294002 46.5 +/- 5.0, pioglitazone + wortmannin 48.8 +/- 4.6 versus pioglitazone alone 25.4 +/- 3.1; P < or = 0.05) but not by P42/44MAPK inhibitors (pioglitazone+U0126 30.7 +/- 5.7, pioglitazone + PD98059 28.5 +/- 6.3 versus pioglitazone alone 25.4 +/- 3.1; P < or = 0.05) given in stabilization. However when the inhibitors were given at reperfusion, the protection was abrogated by blocking either pathway (pioglitazone+LY294002 49.8 +/- 3.1, pioglitazone+U0126 48.7 +/- 3.7 versus pioglitazone alone 25.4 +/- 3.1; P < or = 0.05). In conclusion pioglitazone induced significant protection against ischemia/reperfusion injury when administered prior to ischemia. This protection appears to involve PI3K and P42/44MAPK.

Animals↗
PubMed2005

Effect of pioglitazone on metabolic syndrome risk factors: results of double-blind, multicenter, randomized clinical trials.

OBJECTIVE: To evaluate the effect of pioglitazone, metformin, and/or sulfonylurea on metabolic syndrome and its component parameters after a year of treatment. METHODS: Adult patients with poorly controlled type 2 diabetes were enrolled in 4 multicenter, double-blind studies and received pioglitazone, sulfonylurea, metformin, or a combination of any 2 agents. Post hoc analyses were performed on data from patients with evaluations at baseline and week 52, and treatment groups were compared to determine change from baseline in metabolic syndrome status and its component variables by using the McNemar test and analysis of covariance, respectively. RESULTS: Most patients (72.1%) had metabolic syndrome at baseline. Change in the proportion of patients with metabolic syndrome status was significant in each monotherapy and the pioglitazone plus metformin combination groups. Pioglitazone alone or in combination with metformin resulted in a significantly greater percent decrease from baseline in triglycerides (pioglitazone vs. metformin, 10.3%; pioglitazone vs. sulfonylurea, 6.5%; pioglitazone plus metformin vs. sulfonylurea plus metformin, 13.4%; P < 0.05) and a greater percent increase from baseline in high-density lipoprotein (HDL) cholesterol (pioglitazone vs. metformin, 9.1%; pioglitazone vs. sulfonylurea, 12.6%; pioglitazone plus metformin vs. sulfonylurea plus metformin, 17.8%; P < 0.001) at week 52 than did the respective comparison groups. A significant decrease from baseline in the ratio of urinary albumin to creatinine was found only with pioglitazone monotherapy (-1.764 mg/ mmol; P < 0.001), which was significantly greater than the change in the metformin monotherapy group (2.1%; P < 0.05). Significant decrease in blood pressure was observed in the pioglitazone monotherapy and pioglitazone plus sulfonylurea groups, with no significant treatment group differences. CONCLUSIONS: Treatment with pioglitazone as monotherapy or combination therapy led to sustained, positive effects on important components of metabolic syndrome in patients with type 2 diabetes, independent of effects on blood glucose control and, as such, could be translated to potential for reducing the risk of cardiovascular disease.

Adult↗
PubMed2004

Pioglitazone is effective therapy for elderly patients with type 2 diabetes mellitus.

BACKGROUND: Pioglitazone as monotherapy and in combination with sulfonylurea, metformin, or insulin has consistently demonstrated improved glycaemic and lipid parameters in patients with type 2 diabetes mellitus. OBJECTIVE: We performed a subanalysis to examine the effect of pioglitazone on glycaemia and lipids in patients <65 and > or =65 years of age in two double-blind, placebo-controlled monotherapy studies and in three separate multi-centre trials. METHOD: In Study 1, 197 patients were randomised to receive pioglitazone 30 mg/day or placebo for 16 weeks. Study 2 was a forced dose-titration trial in patients randomised to receive pioglitazone 7.5/15/30 mg/day, pioglitazone 15/30/45 mg/day, or placebo daily for 26 weeks. Each of the lower dosages was given for at least 4 weeks and the highest dosage for 16 weeks. The three combination studies evaluated efficacy of pioglitazone 30 or 45 mg/day over a 24-week period in combination with sulfonylureas, metformin, or insulin. RESULTS: In both placebo-controlled monotherapy studies, at 16 weeks, and at maximum pioglitazone dosage, 0.53-0.55% and 0.57-1.27% mean reductions from baseline in glycosylated haemoglobin (HbA(1c)) were seen in patients aged <65 (n = 225) and > or =65 (n = 45) years, respectively. There were statistically significant differences between the placebo and pioglitazone groups in each age cohort. Similar effects were observed in fasting plasma glucose (FPG) levels, with 2.03-2.59 mmol/L and 3.20-4.44 mmol/L mean reductions from baseline, respectively, which were significantly different from the changes in the placebo group, but there was no difference between pioglitazone groups. At treatment endpoint in combination trials, pioglitazone added to sulfonylurea produced a mean decrease in HbA(1c) of 0.78-1.61%, and 1.64-1.96% in patients aged <65 (n = 557) and > or =65 (n = 115) years, respectively. Pioglitazone added to metformin produced a mean decrease in HbA(1c) of 0.78-1.03% and 0.78-0.98% in patients aged <65 (n = 686) and > or =65 (n = 112) years, respectively. Pioglitazone added to insulin produced a mean decrease in HbA(1c) of 1.13-1.37% and 1.39-1.66% in patients aged <65 (n = 500) and > or =65 (n = 156) years, respectively. In patients aged > or =65 years, hypoglycaemia was observed in 1 of 14 patients and in 0 of 13 patients in the two monotherapy studies. In the combination studies, the incidence of hypoglycaemia among patients aged > or =65 years was as follows: 26.7-28.8% combined with sulfonylurea; 0-4.4% combined with metformin; and 53.4-56.4% combined with insulin. CONCLUSION: Pioglitazone monotherapy, or added to a sulfonylurea, metformin, or insulin demonstrated no significant differences in effectiveness while exhibiting similar adverse events in patients aged > or =65 years compared with patients aged <65 years. Well-controlled randomised clinical trials are recommended to confirm the impact of pioglitazone therapy on the glycaemic and lipid control in elderly patients with type 2 diabetes.

Adult↗
PubMed2002

Improved glycemic control and lipid profile in a randomized study of pioglitazone compared with acarbose in patients with type 2 diabetes mellitus.

OBJECTIVE: To assess the efficacy of pioglitazone treatment in comparison with that of acarbose treatment in patients with type 2 diabetes mellitus. PARTICIPANTS AND METHODS: In this randomized, parallel-group, open-label study patients were assigned to treatment with either pioglitazone (n = 129) or acarbose (n = 136). During a 1-week run-in patients commenced an individualized dietary regimen which was maintained throughout the study. Patients received the assigned study medication for 26 weeks. Serum glycosylated hemoglobin (HbA1c) levels, insulin resistance and lipid profiles were determined at baseline and at endpoint. RESULTS: Mean HbA1c was reduced from 8.98+/-1.20% to 7.82+/-1.95% with pioglitazone treatment and from 9.03+/-1.32% to 8.55+/-1.96% with acarbose treatment during the 26-week study. The change from baseline to endpoint was significantly greater for pioglitazone compared with acarbose when analyzed for all patients (p < 0.001) and for those who had (p = 0.009) or had not (p < 0.001) received previous medication for diabetes mellitus. Compared with acarbose, pioglitazone produced a significantly greater decrease in fasting glucose, insulin and insulin resistance (p < 0.001 for each). Triglycerides were decreased by 71.1+/-184.1 mg/dl with pioglitazone compared with 38.1+/-171.3 mg/dl with acarbose (p = 0.001 for difference between groups). High density lipoprotein (HDL)-cholesterol level was increased by 7.8+/-10.2 mg/dl with pioglitazone compared with a decrease of 0.8+/-24.1 mg/dl with acarbose (p < 0.001). While serum low density lipoprotein (LDL)-cholesterol levels remained unchanged with both treatment regimens, the decrease from baseline in very low density lipoprotein (VLDL)-cholesterol was significantly greater with pioglitazone than with acarbose (p < 0.04). Pioglitazone decreased systolic blood pressure by 5.6+/-17.7mm Hg compared with a 0.4+/-18.4mm Hg increase during acarbose treatment (p < 0.001). Pioglitazone caused a significantly greater decrease compared with acarbose in serum levels of gamma-glutamyl aminotransferase (p < 0.001) and alanine aminotransferase (p = 0.004). CONCLUSIONS: Six months of pioglitazone treatment decreased insulin resistance and improved glycemic control to a significantly greater extent than acarbose treatment. Pioglitazone was also associated with a significantly improved lipid profile, suggesting a reduction in risk of coronary heart disease.

Acarbose↗
PubMed2006

Pioglitazone, an in vitro inhibitor of CYP2C8 and CYP3A4, does not increase the plasma concentrations of the CYP2C8 and CYP3A4 substrate repaglinide.

OBJECTIVE: Pioglitazone, a thiazolidinedione antidiabetic, inhibits cytochrome P450 (CYP) 2C8 and CYP3A4 enzymes in vitro. Repaglinide, a meglitinide analogue antidiabetic, is metabolised by CYP2C8 and CYP3A4. In patients with type 2 diabetes, the pioglitazone-repaglinide combination has acted synergistically on glycaemic parameters. Our aim was to determine whether pioglitazone increases the plasma concentrations of repaglinide. METHODS: In a randomized, 2-phase cross-over study, 12 healthy volunteers received 30 mg pioglitazone or placebo once daily for 5 days. On day 5, they ingested a single 0.25 mg dose of repaglinide 1 h after the last pretreatment dose. Plasma repaglinide and pioglitazone, and blood glucose concentrations were measured for 12 h. RESULTS: During the pioglitazone phase, the mean peak plasma repaglinide concentration (C(max)) and the total area under the concentration-time curve [AUC(0-infinity)] of repaglinide were 100% (range 53-157%, P=0.99) and 90% (range 63-120%, P=0.22), respectively, of those during the placebo phase. Also the half-life of repaglinide was unaffected, but the median peak time of repaglinide was shortened from 40 min to 20 min by pioglitazone (P=0.014). The short-term pioglitazone administration did not modify the blood glucose-lowering effect of a single dose of repaglinide. CONCLUSIONS: Pioglitazone does not increase the plasma concentrations of repaglinide, indicating that the inhibitory effect of pioglitazone on CYP2C8 and CYP3A4 is very weak in vivo, probably due to its extensive plasma protein binding. The synergistic effect of repaglinide and pioglitazone on the glycaemic parameters, seen in patients with type 2 diabetes during their long-term use, is unlikely to be caused by inhibition of repaglinide metabolism by pioglitazone.

Administration, Oral↗
PubMed1998

The effect of pioglitazone on glucose metabolism and insulin uptake in the perfused liver and hindquarter of high-fructose-fed rats.

To investigate the effect of pioglitazone, a thiazolidinedione oral antidiabetic agent, on the glucose and insulin metabolism in insulin resistance, a perfusion study of the liver and hindquarter was performed in high-fructose-fed rats. Male Wistar albino rats were assigned randomly to one of the following diets for 2 weeks: (1) normal chow (control group), (2) a diet high in fructose (fructose group), or (3) a high-fructose diet plus pioglitazone (pioglitazone intake of approximately 10 mg/kg body weight; pioglitazone group). The elevated levels of plasma insulin, triglyceride, and free fatty acids (FFA) in the fructose group were normalized by pioglitazone administration. In the perfused liver, the glucagon-induced increment in the glucose output of the fructose (57.1+/-9.1 micromol/g liver/20 min) and pioglitazone (44.7+/-10.1 micromol/g liver/20 min) groups was significantly (P < .01) higher than that in the control group (27.6+/-5.7 micromol/g liver/20 min). The level in the pioglitazone group was significantly (P < .05) lower than that in the fructose group. In the presence of 100 or 500 microU/mL insulin, the insulin-mediated decrement in the glucagon-induced glucose output of the fructose group (29.8+/-7.8 or 38.9+/-9.3 micromol/g liver/20 min) was significantly (P < .05) lower than that in the control (45.8+/-14.2 or 54.5+/-8.5 micromol/g liver/20 min) and pioglitazone (44.4+/-9.2 or 56.2+/-10.8 micromol/g liver/20 min) groups, respectively. In the perfused hindquarter, glucose uptake in the fructose group (8.2+/-2.0 micromol/g muscle/30 min) was significantly (P < .05) lower than that in the control (12.1+/-2.3 micromol/g muscle/30 min) and pioglitazone (11.8+/-3.1 micromol/g muscle/30 min) groups. In the presence of 100 or 500 microU/mL insulin, glucose uptake in the fructose group (12.0+/-5.2 or 17.4+/-3.0 micromol/g muscle/30 min) was significantly (P < .05) lower than that in the control (20.2+/-2.4 or 23.0+/-3.1 micromol/g muscle/30 min) and pioglitazone (17.8+/-2.4 or 20.7+/-2.0 micromol/g muscle/30 min) groups, respectively. Insulin uptake by the liver and hindquarter was not significantly different in the control, fructose, and pioglitazone groups. These results indicate that pioglitazone improves the increased glucagon-induced hepatic glucose output and decreases insulin-induced muscular glucose uptake without altering insulin uptake in high-fructose-fed insulin-resistant rats.

Animals↗