Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.20 (alpha-glucosidase)
 4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The biguanide metformin (dimethylbiguanide) is an oral antihyperglycaemic agent widely used in the management of non-insulin-dependent diabetes mellitus (NIDDM). Considerable renewal of interest in this drug has been observed in recent years. Metformin can be determined in biological fluids by various methods, mainly using high performance liquid chromatography, which allows pharmacokinetic studies in healthy volunteers and diabetic patients. Metformin disposition is apparently unaffected by the presence of diabetes and only slightly affected by the use of different oral formulations. Metformin has an absolute oral bioavailability of 40 to 60%, and gastrointestinal absorption is apparently complete within 6 hours of ingestion. An inverse relationship was observed between the dose ingested and the relative absorption with therapeutic doses ranging from 0.5 to 1.5 g, suggesting the involvement of an active, saturable absorption process. Metformin is rapidly distributed following absorption and does not bind to plasma proteins. No metabolites or conjugates of metformin have been identified. The absence of liver metabolism clearly differentiates the pharmacokinetics of metformin from that of other biguanides, such as phenformin. Metformin undergoes renal excretion and has a mean plasma elimination half-life after oral administration of between 4.0 and 8.7 hours. This elimination is prolonged in patients with renal impairment and correlates with creatinine clearance. There are only scarce data on the relationship between plasma metformin concentrations and metabolic effects. Therapeutic levels may be 0.5 to 1.0 mg/L in the fasting state and 1 to 2 mg/L after a meal, but monitoring has little clinical value except when lactic acidosis is suspected or present. Indeed, when lactic acidosis occurs in metformin-treated patients, early determination of the metformin plasma concentration appears to be the best criterion for assessing the involvement of the drug in this acute condition. After confirmation of the diagnosis, treatment should rapidly involve forced diuresis or haemodialysis, both of which favour rapid elimination of the drug. Although serious, lactic acidosis due to metformin is rare and may be minimised by strict adherence to prescribing guidelines and contraindications, particularly the presence of renal failure. Finally, only very few drug interactions have been described with metformin in healthy volunteers. Plasma levels may be reduced by guar gum and alpha-glucosidase inhibitors and increased by cimetidine, but no data are yet available in the diabetic population.
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PMID:Clinical pharmacokinetics of metformin. 874 35

Gastrectomy or vagotomy may result in reactive hypoglycemia, which, in some cases, can reduce the plasma glucose levels to 30-40 mg/dl due to rapid digestion and absorption of food, especially carbohydrates. It also occurs sometimes in patients on hemodialysis, where it is a potentially lethal complication. Because insulin has a longer half-life due to lack of renal degradation, hypoglycemia can be induced by insulin in patients with renal failure. We treated a patient with frequent episodes of severe hypoglycemia, that were sometimes accompanied by convulsions. He had undergone total gastrectomy 8 years before and had been maintained on hemodialysis for 3 years. Hyperinsulinemia caused by oxyhyperglycemia associated with post-gastrectomy led to severe hypoglycemia in this patient because of the lack of renal insulin degradation. Since nutritional treatment did not successfully manage his reactive hypoglycemia, an alpha-glucosidase inhibitor, acarbose, was administered to treat his oxyhyperglycemia. This therapy was very effective and he has not had any recurrence of reactive hypoglycemia since the initiation of the therapy.
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PMID:Treatment with alpha-glucosidase inhibitor for severe reactive hypoglycemia: a case report. 1107 24

Classical non-insulin antihyperglycemic drugs currently approved for the treatment of type 2 diabetes mellitus (T2DM) comprise five groups: biguanides, sulfonylureas, meglitinides, glitazones and alpha-glucosidase inhibitors. Novel compounds are represented by the incretin mimetic drugs like glucagon like peptide-1 (GLP-1), the dipeptidyl peptidase 4 (DPP-4) inhibitors, dual peroxisome proliferator-activated receptors (PPAR) agonists (glitazars) and amylin mimetic drugs. We review the cardiovascular effects of these drugs in an attempt to improve knowledge regarding their potential risks when treating T2DM in cardiac patients. Metformin may lead to lethal lactic acidosis, especially in patients with clinical conditions that predispose to this complication, such as recent myocardial infarction, heart or renal failure. Sulfonylureas exert their effect by closing the ATP-dependent potassium channels. This prevents the opening of these channels during myocardial ischemia, impeding the necessary hyperpolarization that protects the cell. The combined sulfonylurea/metformin therapy reveals additive effects on mortality in patients with coronary artery disease (CAD). Meglitinides effects are similar to those of sulfonylureas, due to their almost analogous mechanism of action. Glitazones lower leptin levels, leading to weight gain and are unsafe in NYHA class III or IV. The long-term effects of alpha-glucosidase inhibitors on morbidity and mortality rates is yet unknown. The incretin GLP-1 is associated with reductions in body weight and appears to present positive inotropic effects. DPP-4 inhibitors influences on the cardiovascular system seem to be neutral and patients do not gain weight. The future of glitazars is presently uncertain following concerns about their safety. The amylin mimetic drug paramlintide, while a satisfactory adjuvant medication in insulin-dependent diabetes, is unlikely to play a major role in the management of T2DM. Summarizing the present information it can be stated that 1. Four out the five classical oral antidiabetic drug groups present proven or potential cardiac hazards; 2. These hazards are not mere 'side effects', but biochemical phenomena which are deeply rooted in the drugs' mechanism of action; 3. Current data indicate that the combined glibenclamide/metformin therapy seems to present special risk and should be avoided in the long-term management of T2DM with proven CAD; 4. Glitazones should be avoided in patients with overt heart failure; 5, The novel incretin mimetic drugs and DPP-4 inhibitors--while usually inadequate as monotherapy--appear to be satisfactory adjuvant drugs due to the lack of known undesirable cardiovascular effects; 6. Customized antihyperglycemic pharmacological approaches should be implemented for the achievement of optimal treatment of T2DM patients with heart disease. In this context, it should be carefully taken into consideration whether the leading clinical status is CAD or heart failure.
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PMID:A cardiologic approach to non-insulin antidiabetic pharmacotherapy in patients with heart disease. 1961 27