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Glossmann H, Reider N. A marriage of two "Methusalem" drugs for the treatment of psoriasis?: Arguments for a pilot trial with metformin as add-on for methotrexate. DERMATO-ENDOCRINOLOGY 2014; 5:252-63. [PMID: 24194965 PMCID: PMC3772913 DOI: 10.4161/derm.23874] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 02/04/2013] [Indexed: 02/06/2023]
Abstract
In this article we present arguments that the “antidiabetic” drug metformin could be useful as an add-on therapy to methotrexate for the treatment of psoriasis and, perhaps, for rheumatoid arthritis as well. Biochemical data suggest that both drugs may share a common cellular target, the AMP-activated protein kinase (AMPK). This enzyme is a master regulator of metabolism and controls a number of downstream targets, e.g., important for cellular growth or function in many tissues including T-lymphocytes. Clinical observations as well as experimental results argue for anti-inflammatory, antineoplastic and antiproliferative activities of metformin and a case-control study suggests that the drug reduces the risk for psoriasis.
Patients with psoriasis have higher risk of metabolic syndrome, type 2 diabetes and cardiovascular mortality. Metformin has proven efficacy in the treatment of prediabetes and leads to a pronounced and sustained weight loss in overweight individuals. We expect that addition of metformin to methotrexate can lead to positive effects with respect to the PASI score, reduction of the weekly methotrexate dose and of elevated cardiovascular risk factors in patients with metabolic syndrome and psoriasis. For reasons explained later we suggest that only male, overweight patients are to be included in a pilot trial. On the other side of the coin are concerns that the gastrointestinal side effects of metformin are intolerable for patients under low dose, intermittent methotrexate therapy. Metformin has another side effect, namely interference with vitamin B12 and folate metabolism, leading to elevated homocysteine serum levels. As patients must receive folate supplementation and will be controlled with respect to their B12 status increased hematological toxicity is unlikely to result.
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Affiliation(s)
- Hartmut Glossmann
- Institute for Biochemical Pharmacology; Department of Dermatology; Medical University of Innsbruck; Innsbruck, Austria
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Abstract
Metformin has been the mainstay of therapy for diabetes mellitus for many years; however, the mechanistic aspects of metformin action remained ill-defined. Recent advances revealed that this drug, in addition to its glucose-lowering action, might be promising for specifically targeting metabolic differences between normal and abnormal metabolic signalling. The knowledge gained from dissecting the principal mechanisms by which metformin works can help us to develop novel treatments. The centre of metformin's mechanism of action is the alteration of the energy metabolism of the cell. Metformin exerts its prevailing, glucose-lowering effect by inhibiting hepatic gluconeogenesis and opposing the action of glucagon. The inhibition of mitochondrial complex I results in defective cAMP and protein kinase A signalling in response to glucagon. Stimulation of 5'-AMP-activated protein kinase, although dispensable for the glucose-lowering effect of metformin, confers insulin sensitivity, mainly by modulating lipid metabolism. Metformin might influence tumourigenesis, both indirectly, through the systemic reduction of insulin levels, and directly, via the induction of energetic stress; however, these effects require further investigation. Here, we discuss the updated understanding of the antigluconeogenic action of metformin in the liver and the implications of the discoveries of metformin targets for the treatment of diabetes mellitus and cancer.
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Affiliation(s)
- Ida Pernicova
- Department of Endocrinology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London EC1A 6BQ, UK
| | - Márta Korbonits
- Department of Endocrinology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London EC1A 6BQ, UK
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Ali S, Fonseca V. Overview of metformin: special focus on metformin extended release. Expert Opin Pharmacother 2012; 13:1797-805. [DOI: 10.1517/14656566.2012.705829] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Salpeter SR, Greyber E, Pasternak GA, Salpeter EE. Risk of fatal and nonfatal lactic acidosis with metformin use in type 2 diabetes mellitus. Cochrane Database Syst Rev 2010; 2010:CD002967. [PMID: 20393934 PMCID: PMC7138050 DOI: 10.1002/14651858.cd002967.pub4] [Citation(s) in RCA: 161] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Metformin is an oral anti-hyperglycemic agent that has been shown to reduce total mortality compared to other anti-hyperglycemic agents, in the treatment of type 2 diabetes mellitus. Metformin, however, is thought to increase the risk of lactic acidosis, and has been 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, and to evaluate blood lactate levels, for those on metformin treatment compared to placebo or non-metformin therapies. SEARCH STRATEGY A comprehensive search was performed of electronic databases to identify studies of metformin treatment. The search was augmented by scanning references of identified articles, and by contacting principal investigators. SELECTION CRITERIA Prospective trials and observational cohort studies in patients with type 2 diabetes of least one month duration were included if they evaluated metformin, alone or in combination with other treatments, compared to placebo or any other glucose-lowering therapy. DATA COLLECTION AND ANALYSIS The incidence of fatal and nonfatal lactic acidosis was recorded as cases per patient-years, for metformin treatment and for non-metformin treatments. The upper limit for the true incidence of cases was 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 347 comparative trials and cohort studies revealed no cases of fatal or nonfatal lactic acidosis in 70,490 patient-years of metformin use or in 55,451 patients-years in the non-metformin group. Using Poisson statistics the upper limit for the true incidence of lactic acidosis per 100,000 patient-years was 4.3 cases in the metformin group and 5.4 cases in the non-metformin group. There was no difference in lactate levels, either as mean treatment levels or as a net change from baseline, for metformin compared to non-metformin therapies. 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.
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Affiliation(s)
- Shelley R Salpeter
- Stanford University, and Santa Clara Valley Medical CenterMedicine2400 Moorpark Ave, Suite 118San JoseCAUSA95128
| | - Elizabeth Greyber
- Santa Clara Valley Medical CenterMedicine2400 Moorpark Ave, Suite 118San JoseCAUSA95128
| | - Gary A Pasternak
- Santa Clara Valley Medical CenterMedicine2400 Moorpark Ave, Suite 118San JoseCAUSA95128
| | - Edwin E Salpeter
- Cornell UniversityCenter for Radiophysics and Space Research612 Space Sciences BuildingIthacaNYUSA14853
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Salpeter SR, Greyber E, Pasternak GA, Salpeter Posthumous EE. Risk of fatal and nonfatal lactic acidosis with metformin use in type 2 diabetes mellitus. Cochrane Database Syst Rev 2010:CD002967. [PMID: 20091535 DOI: 10.1002/14651858.cd002967.pub3] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Metformin is an oral anti-hyperglycemic agent that has been shown to reduce total mortality compared to other anti-hyperglycemic agents, in the treatment of type 2 diabetes mellitus. Metformin, however, is thought to increase the risk of lactic acidosis, and has been 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, and to evaluate blood lactate levels, for those on metformin treatment compared to placebo or non-metformin therapies. SEARCH STRATEGY A comprehensive search was performed of electronic databases to identify studies of metformin treatment. The search was augmented by scanning references of identified articles, and by contacting principal investigators. SELECTION CRITERIA Prospective trials and observational cohort studies in patients with type 2 diabetes of least one month duration were included if they evaluated metformin, alone or in combination with other treatments, compared to placebo or any other glucose-lowering therapy. DATA COLLECTION AND ANALYSIS The incidence of fatal and nonfatal lactic acidosis was recorded as cases per patient-years, for metformin treatment and for non-metformin treatments. The upper limit for the true incidence of cases was 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 347 comparative trials and cohort studies revealed no cases of fatal or nonfatal lactic acidosis in 70,490 patient-years of metformin use or in 55,451 patients-years in the non-metformin group. Using Poisson statistics the upper limit for the true incidence of lactic acidosis per 100,000 patient-years was 4.3 cases in the metformin group and 5.4 cases in the non-metformin group. There was no difference in lactate levels, either as mean treatment levels or as a net change from baseline, for metformin compared to non-metformin therapies. 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.
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Affiliation(s)
- Shelley R Salpeter
- Medicine, Stanford University, and Santa Clara Valley Medical Center, 2400 Moorpark Ave, Suite 118, San Jose, CA, USA, 95128
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Metformin: effects on micro and macrovascular complications in type 2 diabetes. Cardiovasc Drugs Ther 2008; 22:215-24. [PMID: 18288595 DOI: 10.1007/s10557-008-6092-0] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2008] [Accepted: 01/24/2008] [Indexed: 10/22/2022]
Abstract
INTRODUCTION The antihyperglycaemic agent metformin is widely used in the treatment of type 2 diabetes. Data from the UK Prospective Diabetes Study and retrospective analyses of large healthcare databases concur that metformin reduces the incidence of myocardial infarction and increases survival in these patients. This apparently vasoprotective effect appears to be independent of the blood glucose-lowering efficacy. EFFECTS OF METFORMIN Metformin has long been known to reduce the development of atherosclerotic lesions in animal models, and clinical studies have shown the drug to reduce surrogate measures such as carotid intima-media thickness. The anti-atherogenic effects of metformin include reductions in insulin resistance, hyperinsulinaemia and obesity. There may be modest favourable effects against dyslipidaemia, reductions in pro-inflammatory cytokines and monocyte adhesion molecules, and improved glycation status, benefiting endothelial function in the macro- and micro-vasculature. Additionally metformin exerts anti-thrombotic effects, contributing to overall reductions in athero-thrombotic risk in type 2 diabetic patients.
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Salpeter S, Greyber E, Pasternak G, Salpeter E. Risk of fatal and nonfatal lactic acidosis with metformin use in type 2 diabetes mellitus. Cochrane Database Syst Rev 2006:CD002967. [PMID: 16437448 DOI: 10.1002/14651858.cd002967.pub2] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
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.
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Goodarzi MO, Bryer-Ash M. Metformin revisited: re-evaluation of its properties and role in the pharmacopoeia of modern antidiabetic agents. Diabetes Obes Metab 2005; 7:654-65. [PMID: 16219009 DOI: 10.1111/j.1463-1326.2004.00448.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
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.
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Affiliation(s)
- Mark O Goodarzi
- Department of Medicine and the Gonda (Goldschmied) Diabetes Center, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
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Fogari R, Zoppi A. Is the effect of antihypertensive drugs on platelet aggregability and fibrinolysis clinically relevant? Am J Cardiovasc Drugs 2005; 5:211-23. [PMID: 15984904 DOI: 10.2165/00129784-200505040-00001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Hypertension is associated with decreased fibrinolytic potential, mainly expressed as elevated plasma plasminogen activator inhibitor type 1 (PAI-1) levels, and increased platelet aggregability, which may account in part for the increased risk of atherosclerosis and its clinical complications in hypertensive patients. The effects of antihypertensive drugs on this prothrombotic state have been investigated and controversial findings have been reported, possibly because of differences in study designs, patients selected, and methodology used. Scarce and conflicting data exist about the effects of diuretics and beta-adrenoceptor antagonists on the fibrinolytic system, whereas ACE inhibitors have generally been reported to improve the fibrinolytic balance by decreasing plasma PAI-1 levels, calcium channel antagonists have been shown to increase tissue plasminogen activator (tPA) activity, and angiotensin II type 1 (AT(1)) receptor antagonists seem to exert neutral effects. beta-Adrenoceptor antagonists, calcium channel antagonists, and AT(1)-receptor antagonists have been reported to exert anti-aggregatory effects on platelets, while contrasting data exist about the influence of ACE inhibitors. Clinical implications of the changes induced by antihypertensive drugs on the fibrinolytic balance and platelet function are still debated. In particular, the question of whether these changes may translate into different degrees of cardiovascular protection in hypertensive patients remains unanswered. While awaiting more information from clinical trials, the choice of antihypertensive drugs, particularly in high-risk patients, should take into account effects beyond their BP-lowering efficacy. Selected agents should have a favorable, or at least neutral, impact on fibrinolytic function and platelet activity.
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Affiliation(s)
- Roberto Fogari
- Department of Internal Medicine and Therapeutics, Clinica Medica II, I.R.C.C.S. Policlinico San Matteo, University of Pavia, Pavia, Italy.
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Grant PJ. Beneficial effects of metformin on haemostasis and vascular function in man. DIABETES & METABOLISM 2003; 29:6S44-52. [PMID: 14502100 DOI: 10.1016/s1262-3636(03)72787-6] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Type 2 diabetes is characterised by insulin resistance in association with clustering of atherothrombotic risk factors (dysglycaemia, hyperinsulinaemia, hypertension, raised triglyceride, low HDL cholesterol and increased levels of plasminogen activator inhibitor-1 (PAI-1) and clotting factor VII). There is a 3-5 fold increase in risk of myocardial infarction rising to 10-20 fold in the presence of microalbuminuria and overall around 70-75% of subjects with type 2 diabetes die of cardiovascular disease. However, classical risk factors which associate with insulin resistance do not account for all the increased burden of vascular disease in diabetic subjects. Metformin is a biguanide compound which is antihyperglycaemic, reduces insulin resistance and has cardioprotective effects on lipids, thrombosis and blood flow. Metformin has a weight neutral/weight lowering effect and reduces hypertriglyceridaemia, elevated levels of PAI-1, factor VII and C-reactive protein. In addition recent studies indicate that metformin has direct effects on fibrin structure/function and stabilises platelets, two important components of arterial thrombus. The United Kingdom Prospective Diabetes Study (UKPDS) reported that metformin was associated with a 32% reduction in any diabetes related endpoint (p<0.002), a 39% reduction in myocardial infarction (p<0.01) and a non-significant 29% fall in microvascular complications. The figures for macrovascular complications compare favourably for those described for other cardioprotective agents such as ACE inhibitors and statins. These findings confirm metformin as first line therapy in the management of obese insulin resistant type 2 diabetes and in the prevention of the vascular complications of this common condition.
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Affiliation(s)
- P J Grant
- Academic Unit of Molecular Vascular Medicine, Leeds School of Medicine and General Infirmary at Leeds, Leeds, UK
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Salpeter S, Greyber E, Pasternak G, Salpeter E. Risk of fatal and nonfatal lactic acidosis with metformin use in type 2 diabetes mellitus. Cochrane Database Syst Rev 2003:CD002967. [PMID: 12804446 DOI: 10.1002/14651858.cd002967] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
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 Controlled Trials Register and the Database of Abstracts of Reviews of Effectiveness (up to 4/2000), Medline (up to 11/2000), Embase (up to 11/2000), Oldmedline, and Reactions (up to 5/2000), in order to identify all studies of metformin treatment from 1966 to November 2000. 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: November 2000. 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 effects model for continuous data. MAIN RESULTS Pooled data from 176 comparative trials and cohort studies revealed no cases of fatal or nonfatal lactic acidosis in 35,619 patient-years of metformin use or in 30,002 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 8.4 cases per 100,000 patient-years, and the upper limit for the true incidence of lactic acidosis in the non-metformin group was 9 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). REVIEWER'S 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, taking into account contra-indications.
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Affiliation(s)
- S Salpeter
- Medicine, Stanford University, and Santa Clara Valley Medical Center, 2400 Moorpark Ave, Suite 118, San Jose, CA 95128, USA.
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Brogard JM, Neyrolles N, Andres E, Blicklé JF. [Current status of the treatment of type 2 diabetes mellitus. The revival of insulin-resistance drugs]. Rev Med Interne 1999; 20 Suppl 3:371s-378s. [PMID: 10480188 DOI: 10.1016/s0248-8663(99)80510-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The relief of insulin resistance is one of the two therapeutic targets of the treatment of type 2 diabetes. Insulin-sensitizers are therefore complemental with other oral diabetic drugs. The treatment of insulin resistance was for a long time limited to dietary and exercise programmes, a biguanide, metformine, and benfluorex, a phenylethylamine derivative; the mechanisms of action of both drugs are now better understood and their indications more precisely targeted. A new therapeutic class, the thiazolidinediones (troglitazone, rosiglitazone, pioglitazone) has recently completed the family of insulin-sensitizing agents. These drugs, which should be soon available in France, act by a different way than metformin, which has been recently identified as the peroxisomes proliferator-activated receptor. The role of antilipolytic agents, which might increase glucose uptake by reducing free fatty acid production and oxidation is under evaluation, as well as the potential benefit of orlistat, an inhibitor of lipid digestion which has been proved effective, in addition to hypocaloric diet, in the management of obese patients.
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Affiliation(s)
- J M Brogard
- Service de médecine interne B, hôpital civil, hôpitaux universitaires de Strasbourg, France
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Abstract
AIMS Lactic acidosis is a well recognized complication of biguanide therapy which is potentially serious. Although the prevalence of metformin-associated lactic acidosis (MALA) is much lower than that associated with phenformin, it is still being reported sporadically which raises concerns for the practising clinicians. We review the currently available world-wide data of the prevalence of MALA, the risk factors for its development and the current practical guidelines on the use of metformin to minimize the risk of this potential hazard. METHODS An extensive literature search was conducted from both Medline and Ovid (1965-98) using the following keywords: 'Type 2 diabetes mellitus', 'oral hypoglycaemic drugs', 'biguanides', 'metformin-associated lactic acidosis' and 'renal impairment'. RESULTS MALA was found to be a very rare clinical entity, being 20 times less common than phenformin-associated lactic acidosis. Amongst all the risk factors, renal impairment appears to be the major precipitating factor for the development of MALA in metformin-treated patients. We also found cases of MALA where no precipitating factors were identified and the underlying mechanism in these cases remains unclear. Practical recommendations of metformin use to minimize the risk of MALA have been listed based on previous reports. CONCLUSIONS The low prevalence of MALA is comparable to the prevalence of sulphonylurea-induced hypoglycaemia. Metformin has many beneficial metabolic effects in the management of Type 2 diabetes mellitus. Provided that the recommended guidelines for metformin use are strictly adhered to, its widespread use would be safe and the incidence of MALA will be further reduced.
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Affiliation(s)
- N N Chan
- Diabetes Unit, Medicine Directorate, Imperial College School of Medicine, Chelsea & Westminster Hospital, London. NN KA
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Testa R, Bonfigli AR, Piantanelli L, Manfrini S, Testa I, Gregorio F. Relationship between plasminogen activator inhibitor type-1 plasma levels and the lipoprotein(a) concentrations in non-insulin-dependent diabetes mellitus. Diabetes Res Clin Pract 1996; 33:111-8. [PMID: 8879966 DOI: 10.1016/0168-8227(96)01286-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The first part of the paper deals with the relationship between two inhibiting factors of the complex enzyme cascade regulating fibrinolysis, namely plasminogen activator inhibitor type-1 (PAI-1) and lipoprotein(a) (Lp(a)). Blood concentrations of Lp(a), PAI-1 antigen (PAI-1 AG) and activity (PAI-1 AT), and the main parameters of lipo- and glyco-metabolic balance were studied in 80 type II diabetic patients. Roughly hyperbolic patterns have been found between PAI-1 and Lp(a). Negative statistically significant linear correlation can be elicited when Log PAI-1 AG and Log PAI-1 AT values are plotted versus Lp(a) values, the first one being particularly tight. These findings suggest a nearly on/off control of the two parameters, limiting the risk of hypofibrinolysis. The second part of the paper was aimed at verifying this hypothesis. A group of 30 diabetic patients were treated for 3 months with metformin, an antidiabetic biguanide compound which has been reported to reduce PAI-1 levels both in diabetic and in non-diabetic patients. Metformin significantly reduced PAI-1 AG and PAI-1 AT but did not influence plasma Lp(a) levels. A clear linear correlation between the basal Lp(a) values and the changes in PAI-1 AG levels was found. An even tighter correlation was elicited between the decrease in PAI-1, and PAI-1 pretreatment values.
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Affiliation(s)
- R Testa
- Gerontological Research Dept., Italian National Research Centres on Aging (INRCA), Ancona, Italy
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Abstract
Metformin is contraindicated in patients with renal failure because of the risk of lactic acidosis. This study assessed the complications of metformin treatment in patients with non-insulin-dependent diabetes mellitis with normal and raised serum creatinine. Subjects using metformin with serum creatinine above the upper reference range (120 mu mol/l) were identified (n = 17) from a hospital diabetes register; those with abnormal liver function, cardiac failure, peripheral vascular disease or recent severe illness were excluded. Reference plasma lactate levels were established, mean 1.742 mu mol/l (SD 0.819) using age-matched non-diabetic subjects. Age-matched patients treated with metformin with normal serum creatinine levels formed the control group (n = 24). Details of gastrointestinal disturbance were recorded, and plasma lactic acid and vitamin B12 levels measured. The median total daily dose of metformin in both groups was 1700 mg. The mean plasma lactate in subjects with serum creatinine 80-120 mu mol/l (2.640 mmol/l (SD 1.434) p < 0.02) was higher than non-diabetic control levels while diabetic subjects with serum creatinine 120-160 mumol/l had a mean of 2.272 mmol/l (SD 0.763) p < 0.05. There was no significant difference between the two groups taking metformin, nor any significant difference in the reporting of gastrointestinal symptoms between the groups on metformin (11.76% vs 12.5%). Plasma lactic acid levels are higher in diabetic subjects taking metformin compared with healthy volunteers but, within the diabetic groups, the small elevation of serum creatinine was not associated with higher plasma lactate levels.
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Affiliation(s)
- V Connolly
- Diabetes Centre, Victoria Infirmary NHS Trust, Glasgow, UK
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18
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Grant PJ. The effects of metformin on cardiovascular risk factors. DIABETES/METABOLISM REVIEWS 1995; 11 Suppl 1:S43-50. [PMID: 8529484 DOI: 10.1002/dmr.5610110507] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- P J Grant
- Diabetes and Thrombosis Research Group, University of Leeds, UK
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Abstract
The elevated risk factors classically associated with Syndrome X do not adequately explain the increased cardiovascular risk linked to insulin resistance. Considerable indirect evidence and more limited direct evidence suggests that increases in certain prognostically significant hemostatic variables--notably plasma fibrinogen, factor VII coagulant activity, and plasminogen activator inhibitor-1 levels--may be concomitants of Syndrome X. Increased platelet aggregability, and a reduced capacity of vascular endothelium for prostacyclin generation, may also be associated with insulin resistance. Large clinical studies, involving quantification of insulin sensitivity and measurement of hemostatic variables, are required to test this hypothesis. It is unlikely that hyperinsulinemia mediates the connections between insulin resistance and hemostatic variables (or indeed other risk factors in Syndrome X). In light of the remarkably broad impact of insulin resistance on cardiovascular risk factors, promotion of optimal insulin sensitivity should assume a central role in preventive cardiology.
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20
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Ilarde A, Tuck M. Treatment of non-insulin-dependent diabetes mellitus and its complications. A state of the art review. Drugs Aging 1994; 4:470-91. [PMID: 8075474 DOI: 10.2165/00002512-199404060-00004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Non-insulin-dependent diabetes mellitus (NIDDM) is a major health problem which occurs predominantly in the older population; 16.8% of persons over age 65 years have NIDDM. The total health costs of NIDDM are in excess of $US20 billion annually. The primary objective in the treatment of NIDDM is to achieve normoglycaemia, without aggravating coexisting abnormalities. Common abnormalities include obesity, hypertension, retinopathy, nephropathy and neuropathies. Diet, and consequent bodyweight reduction, is the cornerstone of therapy for NIDDM. Total calorie intake should be limited, while the percentage of calories from carbohydrates should be increased and that from fats and cholesterol should be decreased. Exercise may also help to reduce bodyweight. Sulphonylurea drugs stimulate insulin secretion from beta-cells, and may be a useful adjunct to nonpharmacological therapy. Failure to respond to sulphonylurea drugs may be primary (25 to 30% of initially treated patients) or secondary (5 to 10% per year). It is not clear which is the most effective pharmacological intervention in such cases. Options include switching to or combining therapy with insulin, a biguanide, or other insulin-sparing antihyperglycaemic agents, e.g. alpha-glucosidase inhibitors, thiazolidinediones, chloroquine or hydroxychloroquine, or fibric acid derivatives such as clofibrate. Other experimental agents include the fatty acid oxidation inhibitors and dichloroacetate. Specific agents, such as antihypertensives, lipid lowering agents and sorbitol inhibitors, may be needed to prevent the complications arising from the spectrum of clinical and metabolic abnormalities which arise from insulin resistance.
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Affiliation(s)
- A Ilarde
- University of California, San Fernando Valley Medical Program, Sepulveda
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Anfosso F, Chomiki N, Alessi MC, Vague P, Juhan-Vague I. Plasminogen activator inhibitor-1 synthesis in the human hepatoma cell line Hep G2. Metformin inhibits the stimulating effect of insulin. J Clin Invest 1993; 91:2185-93. [PMID: 8387542 PMCID: PMC288221 DOI: 10.1172/jci116445] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
High plasma plasminogen activator inhibitor-1 (PAI-1) activity is associated with insulin resistance and is correlated with hyperinsulinemia. The cellular origin of plasma PAI-1 in insulin resistance is not known. The hepatoma cell line Hep G2 has been shown to synthesize PAI-1 in response to insulin. The aim of this study was to analyze the insulin-mediated response of PAI-1 and lipid synthesis in Hep G2 cells after producing an insulin-resistant state by decreasing insulin receptor numbers. The effect of metformin, a dimethyl-substituted biguanide, known to lower plasma insulin and PAI-1 levels in vivo was concomitantly evaluated. Preincubation by an 18-h exposure of Hep G2 cells to 10(-7) M insulin aimed at reducing the number of insulin receptors, was followed by a subsequent 24-h stimulation with 10(-9) M insulin. The decrease in insulin receptors was accompanied as expected, by a reduction in [14C]acetate incorporation, an index of lipid synthesis, whereas PAI-1 secretion and PAI-1 mRNA expression were enhanced. The addition of metformin did not modify the effect of insulin on insulin receptors or [14C]acetate incorporation. In contrast, the drug (10(-4) M) inhibited insulin-mediated PAI-1 synthesis. The results indicate that PAI-1 synthesis in presence of insulin is markedly increased in down-regulated cells, and that metformin inhibits this effect by acting at the cellular level. These in vitro data are relevant with those found in vivo in insulin-resistant patients. Hep G2 cells may be a suitable model to study PAI-1 regulation in response to hyperinsulinemia.
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MESH Headings
- Acetates/metabolism
- Carbon Radioisotopes
- Carcinoma, Hepatocellular
- Cells, Cultured
- DNA Probes
- Dose-Response Relationship, Drug
- Down-Regulation
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/physiology
- Humans
- Insulin/analogs & derivatives
- Insulin/metabolism
- Insulin/pharmacology
- Insulin Antagonists/pharmacology
- Interleukin-10/pharmacology
- Kinetics
- Liver Neoplasms
- Metformin/pharmacology
- Plasminogen Activator Inhibitor 1/biosynthesis
- Plasminogen Activator Inhibitor 1/genetics
- RNA, Neoplasm/genetics
- RNA, Neoplasm/isolation & purification
- Receptor, Insulin/drug effects
- Receptor, Insulin/metabolism
- Recombinant Proteins/pharmacology
- Tetradecanoylphorbol Acetate/pharmacology
- Tumor Cells, Cultured
- Umbilical Veins
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Affiliation(s)
- F Anfosso
- Laboratory of Hematology, Centre Hospitalier Universitaire Timone, Marseille, France
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22
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Juhan-Vague I, Alessi MC, Vague P. Increased plasma plasminogen activator inhibitor 1 levels. A possible link between insulin resistance and atherothrombosis. Diabetologia 1991; 34:457-62. [PMID: 1916049 DOI: 10.1007/bf00403280] [Citation(s) in RCA: 410] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
According to recent prospective studies, hypofibrinolysis due to elevated plasma plasminogen activator inhibitor 1 levels appears to be an independent risk factor for myocardial reinfarction in men, and hyperinsulinaemia, a major indicator of insulin resistance is considered as a risk factor for coronary disease. It has recently been shown that insulin resistance is accompanied by an increased plasma plasminogen activator inhibitor 1 concentration: A significant correlation coefficient was demonstrated between plasminogen activator inhibitor 1 and fasting plasma insulin in the normal population, in obese subjects, in Type 2 (non-insulin-dependent) diabetic patients and in angina pectoris. Attempts to decrease insulin resistance such as fasting, diet, or administration of an oral anti-diabetic drug such as Metformin induced a parallel decrease in plasma insulin and plasminogen activator inhibitor 1 levels. This inhibitor is produced by endothelial cells and by hepatocytes in culture. Plasminogen activator inhibitor 1 synthesis by hepatocytes in culture was stimulated by an increasing insulin concentration, or low density lipoproteins, whereas the endothelial cell synthesis was stimulated by very low density lipoproteins especially when they were obtained from hypertriglyceridaemic patients. Therefore, a direct effect of insulin or lipoprotein changes on the cells which synthesize plasminogen activator inhibitor 1 could be responsible for its increased plasma concentration in insulin resistance states. The increase in plasma plasminogen activator inhibitor 1 levels linked to hyperinsulinaemia is a tempting partial explanation for the association between insulin resistance and coronary disease.
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Affiliation(s)
- I Juhan-Vague
- Laboratory of Haematology, CHU Timone, Marseille, France
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Grant PJ, Stickland MH, Booth NA, Prentice CR. Metformin causes a reduction in basal and post-venous occlusion plasminogen activator inhibitor-1 in type 2 diabetic patients. Diabet Med 1991; 8:361-5. [PMID: 1713132 DOI: 10.1111/j.1464-5491.1991.tb01610.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The effects of metformin on the fibrinolytic system were studied pre- and post-venous occlusion in 38 Type 2 diabetic patients in a double-blind, placebo-controlled trial. After a 3-week run-in period, 21 patients received metformin and 17 placebo, for 6 weeks. In the metformin-treated patients basal plasminogen activator inhibitor-1 antigen (PAI-1Ag) fell from 57.4 micrograms l-1 before treatment to 36.1 (p less than 0.05) and 41.0 micrograms l-1 (p less than 0.01) after 3 and 6 weeks therapy. In this group post-venous occlusion PAI-1Ag also fell after 3 weeks (p less than 0.002) and 6 weeks (p less than 0.05) treatment. There were no changes in either basal or post-venous occlusion concentrations of PAI-1Ag in the placebo treated group. The fall in PAI-1Ag was not associated with an increase in basal plasminogen activator activity (PAA) which remained unchanged in both groups. Post-venous occlusion values for PAA in the metformin treated patients were increased at 3 weeks (p less than 0.05) although there was no difference at 6 weeks.
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Affiliation(s)
- P J Grant
- University Department of Medicine, Leeds, UK
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Abstract
The hyperglycaemia of NIDDM is associated with insulin resistance due, in part, to reduced insulin receptor binding and more especially postreceptor defects. Metformin is an antihyperglycaemic agent which can be used to ameliorate insulin resistance. It appears to act directly on insulin target cells to enhance insulin action. Although metformin may increase insulin-receptor binding, its main effect appears to be directed at the postreceptor level of insulin action. Accordingly the drug potentiates insulin-suppression of hepatic gluconeogenesis and increases insulin-mediated peripheral glucose uptake and metabolism. It does not stimulate insulin release, does not cause weight gain and does not cause clinical hypoglycaemia. The risk of lactate accumulation should be appreciated in patients with renal insufficiency, liver dysfunction and following acute illness with hypoxia, when therapy should be stopped. Although metformin is often bracketed with phenformin in the context of lactic acidosis, different pharmacodynamics and adherence to prescribing guidelines render such a comparison unwarranted.
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Gormsen J, Laursen B. Studies on pharmacological enhancement of blood fibrinolytic activity. Angiology 1970; 21:546-51. [PMID: 4990278 DOI: 10.1177/000331977002100807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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31
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Roberts PS, Burkat RK. The effects of biguanides on the reactions of thrombin and on the 1-stage prothrombin time of standard human plasma. Ann N Y Acad Sci 1968; 148:714-23. [PMID: 5241471 DOI: 10.1111/j.1749-6632.1968.tb27743.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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32
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Mirsky S. Influence of hypoglycemic therapy on blood lipids and body weight in diabetes mellitus. Ann N Y Acad Sci 1968; 148:937-44. [PMID: 4872314 DOI: 10.1111/j.1749-6632.1968.tb27768.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Roberts HJ. Delayed thrombophlebitis and systemic complications after vasectomy: possible role of diabetogenic hyperinsulinism. J Am Geriatr Soc 1968; 16:267-80. [PMID: 5642077 DOI: 10.1111/j.1532-5415.1968.tb00736.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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35
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Fearnley GR, Chakrabarti R, Hocking ED. Fibrinolytic effects of diguanides plus ethyloestrenol in occlusive vascular disease. Lancet 1967; 2:1008-11. [PMID: 4168522 DOI: 10.1016/s0140-6736(67)90286-3] [Citation(s) in RCA: 80] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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36
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Hocking ED, Chakrabarti R, Evans J, Fearnley GR. Effect of biguanides and atromid on fibrinolysis. JOURNAL OF ATHEROSCLEROSIS RESEARCH 1967; 7:121-30. [PMID: 6034469 DOI: 10.1016/s0368-1319(67)80074-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Schwartz MJ, Mirsky S, Schaefer LE. The effect of phenformin hydrochloride on serum cholesterol and triglyceride levels of the stable adult diabetic. Metabolism 1966; 15:808-22. [PMID: 5929037 DOI: 10.1016/0026-0495(66)90173-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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