Saturday, May 1, 2010

المحاضرة الثانية اعداد د اسلام عبد العظيم

WE HAVE STARTED IN THE LAST LECTURE WITH
AGENT USED FOR TREATEMENT OF DM
Lets continue;

2-Meglitinides
Meglitinides help the pancreas produce insulin and are often called "short-acting secretagogues." By closing the potassium channels of the pancreatic beta cells, they open the calcium channels, hence enhancing insulin secretion.
They are taken with or shortly before meals to boost the insulin response to each meal. If a meal is skipped, the medication is also skipped.
• repaglinide (Prandin)
• nateglinide (Starlix)

3-Biguanides
Biguanides reduce hepatic glucose output and increase uptake of glucose by the periphery, including skeletal muscle. Although it must be used with caution in patients with impaired liver or kidney function, metformin, a biguanide, has become the most commonly used agent for type 2 diabetes in children and teenagers. Amongst common diabetic drugs, metformin is the only widely used oral drug that does not cause weight gain.
• metformin (Glucophage).
• phenformin (DBI): used from 1960s through 1980s, withdrawn due to lactic acidosis risk.
• buformin: also withdrawn due to lactic acidosis risk.
• Metformin is usually the first-line medication used for treatment of type-2 diabetes. It is generally prescribed at initial diagnosis in conjunction with exercise and weight loss as opposed to in the past, where Metformin was prescribed after diet and exercise had failed. Initial dosing is 500 mg once daily, then if need be increased to 500 mg twice daily up to 1000 mg twice daily. It is also available in combination with other oral diabetic medications.

4-Thiazolidinediones
Thiazolidinediones (TZDs), also known as "glitazones," bind to PPARγ, a type of nuclear regulatory protein involved in transcription of genes regulating glucose and fat metabolism. These PPARs act on Peroxysome Proliferator Responsive Elements (PPRE [1]). The PPREs influence insulin sensitive genes, which enhance production of mRNAs of insulin dependent enzymes. The final result is better use of glucose by the cells.
• rosiglitazone (Avandia)
• pioglitazone (Actos)
• troglitazone (Rezulin): used in 1990s, withdrawn due to hepatitis and liver damage risk.

5-Alpha-glucosidase inhibitors
Alpha-glucosidase inhibitors are "diabetes pills" but not technically hypoglycemic agents because they do not have a direct effect on insulin secretion or sensitivity. These agents slow the digestion of starch in the small intestine, so that glucose from the starch of a meal enters the bloodstream more slowly, and can be matched more effectively by an impaired insulin response or sensitivity. These agents are effective by themselves only in the earliest stages of impaired glucose tolerance, but can be helpful in combination with other agents in type 2 diabetes.
• acarbose (Precose/Glucobay)