SULFONYLUREAS
Sulfonylureas work primarily by stimulating pancreatic insulin secretion, which in turn reduces hepatic glucose output and increases peripheral glucose disposal.
The sulfonylureas are often classified as belonging to the first or second generation.
The First generation sulfonylureas:
* Acetohexamide
* Chlorpropamide
* Tolazamide
* Tolbutamide.
The Second generation sulfonylureas :
* Glibenclamide
* Glyburide
* Glipizide
* Glicazide
* Glimepiride
The first generation sulfonylureas are rarely used now.
BIGUANIDES
Two drugs in this category are phenformin and metformin.
Biguanides work mainly by
* Suppressing excessive hepatic glucose production
* Increasing glucose utilization in peripheral tissues to a lesser degree.
* Possibly reduce food intake and thus reduce intestinal glucose absorption
As the biguanides do not stimulate endogenous insulin secretion, hypoglycemia does not occur when they are used alone and therefore they are sometimes called anti-hyperglycemic agents rather hypoglycemic agents.
The use of phenformin has decreased considerably and it is usually metformin that is now used when a biguanide is prescribed.
ALPHA-GLUCOSIDASE INHIBITORS
Acarbose is an alpha-glucosidase inhibitor that slows down the breakdown of disaccharides and polysaccharides and other complex carbohydrates into monosaccharides. The enzymatic generation and subsequent absorption of glucose is delayed and the postfood blood glucose values, which are characteristically high in patients with type II diabetes, are reduced.
MEGLITINIDES
A very recent addition to the OHA group. It is a ultra short acting drug which acts directly on the the beta cells of the pancreas and increases the secretion of insulin. It also corrects the problems with the pulsatile release of insulin which is seen in Type II diabetes.
THIAZOLINEDIONES
Thiazolidinediones are a new class of oral antidiabetic agents (commercially known as glitazones) that enhance insulin sensitivity in peripheral tissues. Troglitazone was the first glitazone introduced to the market, and though widely used, it has now been withdrawn from the market as its use has been linked with hepatocellular injury and death secondary to liver failure.
Rosiglitazone and Pioglitazone are now available for clinical use and are extremely potent in reducing peripheral insulin resistance.
Thursday, February 12, 2009
INSULIN
Insulin and its analogs lower blood glucose levels by stimulating peripheral glucose uptake, especially by skeletal muscle and fat, and by inhibiting hepatic glucose production. Insulin inhibits lipolysis, proteolysis, and enhances protein synthesis.
A COMBINATION OF INSULIN AND ORAL HYPOGLYCEMIC AGENTS is given if diabetes is already severe and treatment with OHAs is not anymore that effective.
PITFALLS OF THE COMBINATION
- Hypoglycaemia
- Bleeding at the injection site
I. Is there a role of anticoagulants in hypertension in diabetic patients?
YES. As to the description of anticoagulants, they are used to stop platelets, or heavy cells, present in blood plasma from forming clots. They are most used in those who are at risk for heart attack, stroke, or aneurisms. A blood thinner can be composed of several different chemical formations. Thus, they are useful treatment for hypertension in diabetic patients since one of the causes of hypertension is atherosclerosis.
II. What is the ideal hypertensive drug for diabetic patients?
Strategy of drug therapy in hypertensive diabetes:
The ideal strategy for treating hypertension in persons with diabetes is still not clear. Initial drugs for those with a blood pressure ≧140/90 mm Hg should be with a drug class shown to reduce CVD events in patients with diabetes which include ACE inhibitors, ARBs, low-dose thiazide diuretics, ß-blockers, and calcium channel blockers. Though there is no conclusive evidence favoring one class of drugs, as large number of studies in patients with diabetes (both type 1 and type 2) and hypertension (either mild or more severe) demonstrating improvement in a range of outcomes, including progression of nephropathy, cardiovascular events, and mortality, it is now an established practice to begin hypertensive patients with diabetes and without microalbuminuria on an ACE inhibitor. When microalbuminuria or more advanced stages of nephropathy is present, both ACE inhibitors (T1DM and T2DM patients) and ARBs (T2DM patients) are considered first-line therapy for preventing the progression of nephropathy. However, other strategies including diuretic and b-blocker-based therapy are also supported by evidence. If the target BP goal of ＜130/80 mmHg is not obtained with the initial doses of first-line drugs, increases in doses are recommended, or the addition of a second drug from a different group should be considered. Regardless of the initial treatment, it must be emphasized that most patients will require more than two drugs to achieve the recommended target of ＜130/80 mmHg, and many will require three or more. Achievement of the target BP may be more important than the particular drug regimen used. Thiazide diuretics have been shown to improve cardiovascular outcomes and may address the volume or salt-sensitive components of hypertension, complementing the mechanisms of action of other drugs, so these are appropriate choices for a second or third drug and can be used for initial therapy in patients without additional cardiovascular risk factors (e.g. dyslipidemia) or proteinuria. Actually the JNC VII suggests diuretics, either use alone or in combination, should be the initial drug to be used in patients with hypertension. NDCCBs can be used when ACE inhibitors, ARBs, or ß-blockers are not tolerated or are contraindicated or when a second or third drug is required. Actually classes of drugs for which there are no long-term data on efficacy in improving outcomes can be used when there is intolerance to other classes, when there are specific indications for their use apart from treatment of hypertension (for example, a1-blockers for patients with benign prostatic hypertrophy and diltiazem for rate control in atrial fibrillation), or when additional drugs are required to achieve the target for blood pressure.
Treatment decisions should, of course, be individualized based on the clinical characteristics of the patient, including comorbidities as well as tolerability, personal preference, and cost, and in elderly hypertensive patients, blood pressure should be lowered gradually to avoid complications.
A COMBINATION OF INSULIN AND ORAL HYPOGLYCEMIC AGENTS is given if diabetes is already severe and treatment with OHAs is not anymore that effective.
PITFALLS OF THE COMBINATION
- Hypoglycaemia
- Bleeding at the injection site
I. Is there a role of anticoagulants in hypertension in diabetic patients?
YES. As to the description of anticoagulants, they are used to stop platelets, or heavy cells, present in blood plasma from forming clots. They are most used in those who are at risk for heart attack, stroke, or aneurisms. A blood thinner can be composed of several different chemical formations. Thus, they are useful treatment for hypertension in diabetic patients since one of the causes of hypertension is atherosclerosis.
II. What is the ideal hypertensive drug for diabetic patients?
Strategy of drug therapy in hypertensive diabetes:
The ideal strategy for treating hypertension in persons with diabetes is still not clear. Initial drugs for those with a blood pressure ≧140/90 mm Hg should be with a drug class shown to reduce CVD events in patients with diabetes which include ACE inhibitors, ARBs, low-dose thiazide diuretics, ß-blockers, and calcium channel blockers. Though there is no conclusive evidence favoring one class of drugs, as large number of studies in patients with diabetes (both type 1 and type 2) and hypertension (either mild or more severe) demonstrating improvement in a range of outcomes, including progression of nephropathy, cardiovascular events, and mortality, it is now an established practice to begin hypertensive patients with diabetes and without microalbuminuria on an ACE inhibitor. When microalbuminuria or more advanced stages of nephropathy is present, both ACE inhibitors (T1DM and T2DM patients) and ARBs (T2DM patients) are considered first-line therapy for preventing the progression of nephropathy. However, other strategies including diuretic and b-blocker-based therapy are also supported by evidence. If the target BP goal of ＜130/80 mmHg is not obtained with the initial doses of first-line drugs, increases in doses are recommended, or the addition of a second drug from a different group should be considered. Regardless of the initial treatment, it must be emphasized that most patients will require more than two drugs to achieve the recommended target of ＜130/80 mmHg, and many will require three or more. Achievement of the target BP may be more important than the particular drug regimen used. Thiazide diuretics have been shown to improve cardiovascular outcomes and may address the volume or salt-sensitive components of hypertension, complementing the mechanisms of action of other drugs, so these are appropriate choices for a second or third drug and can be used for initial therapy in patients without additional cardiovascular risk factors (e.g. dyslipidemia) or proteinuria. Actually the JNC VII suggests diuretics, either use alone or in combination, should be the initial drug to be used in patients with hypertension. NDCCBs can be used when ACE inhibitors, ARBs, or ß-blockers are not tolerated or are contraindicated or when a second or third drug is required. Actually classes of drugs for which there are no long-term data on efficacy in improving outcomes can be used when there is intolerance to other classes, when there are specific indications for their use apart from treatment of hypertension (for example, a1-blockers for patients with benign prostatic hypertrophy and diltiazem for rate control in atrial fibrillation), or when additional drugs are required to achieve the target for blood pressure.
Treatment decisions should, of course, be individualized based on the clinical characteristics of the patient, including comorbidities as well as tolerability, personal preference, and cost, and in elderly hypertensive patients, blood pressure should be lowered gradually to avoid complications.
SOURCES
www.diabetesindia.com/diabetes/oral_hypoglycemic_agents.htm
www.vghks.gov.tw/meta/hclam/2004dmht.htm
www.drugs.com
www.vghks.gov.tw/meta/hclam/2004dmht.htm
www.drugs.com
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