They are
For people with type 2 diabetes drugs approved are
1. Exenatide injection (Byetta)
2. Sitagliptin (Januvia)
3. Pramlintide acetate (Symlin)
For those with type 1 diabetes along with insulin Pramlintide acetate (Symlin) can be tried.
Why this drugs are useful in diabetes?
Insulin secretion from pancreas is stimulated by GLUCOSE. These newer drugs target the hormone incretin. Incretins potentiate this glucose stimulated insulin secretion from pancreas. As the insulin synthesizing and secreting action of GLP-1 is preserved in type 2 diabetic patients this has been developed as therapeutic agent for this disease. These are useful in treatment irrespective of the severity and duration of the disease. Diabetes is a chronic progressive disease sometime the agent that works for a period of time may become less effective and ,then we need to introduce new one.
Basic mechanism of action of these drugs.
Incretin are produced in the intestine in response to food intake. Incretin effect is mainly mediated by two peptide hormones, they are glucose-dependent insulin releasing polypeptide(GIP), and glucagon-like peptide-1(GLP-1). Both GIP and GLP-1 are rapidly metabolized into inactive metabolites by the action of dipeptidyl-peptidase-IV (DPP-IV) enzyme. As the insulin synthesizing and secreting action of GLP-1 is preserved in type 2 diabetic patients this has been developed as therapeutic agent. These are useful in treatment irrespective of the severity and duration of the disease. Thus the modulation of GLP-1 levels and GLP-1 activity by administration of the native hormone, its analogs, and mimetics or the agents that inhibit its degradation has become the chief focus of investigation for type 2 diabetes treatment.
Advantage of this drugs in diabetes.
1. They enhance the insulin secretion.In addition to its effects on insulin secretion, GLP-1.
2. Stimulate the insulin synthesis.
3. Inhibit the glucagon secretion ,glucagons increases the blood sugar.
4. Delays the gastric emptying thus reduces the sugar.
5. Reduction of food intake.
6. It has trophic effects on the pancreas. Stimulate betacell proliferation.
Drugs act on GLP1 receptor are
1. Exenatide injection (Byetta)
Indicated in those people with type 2 DM whose blood sugar fails to bring under control with oral drugs. They helps to control the blood sugar by mimicking the insulin action and slowing stomach emptying. Since the patient feel full faster and stop eating these agents will help to reduce weight. This is given as injection 2 times a day at mealtime. Special advantage of this drug is it help to reduce weight and wont produce hypoglycemia. But there is risk of hypoglycemia if taken with other agents that enhance the insulin secretion. Side effect of this drugs are nausea, inflammation of pancreas, risk of kidney disease. Exenatide should not be used in people with kidney disease. Approved for either as single therapeutic agent or in combination with other drugs. To minimize the initial side effect treatment started at lower doses, dose limiting side effect is nausea that is tendency to vomit. Exenatide extended release (Bydureon) advantage of this extended release formulations is it require injection only once a week. Action and side effects are similar to Byetta.
2. Liraglutide (Victora)
Liraglutide is other GLP 1 agonist it is injected once a day. Not used in those people with family history of medullary type of thyroid cancer.
3. Amylin agonist
Pramlintide acetate (Symlin)
Pramlintide acetate is useful for those with type 1 or type 2 diabetes who are on insulin. This is injected at mealtime,it should not be mixed with insulin in same syringe. Advantage of this drug is that it helps to achieve better control of blood sugar, mainly reduce the blood sugar spike after meals. Weight reduction is other added advantage of this drug. This is injected at mealtime. Unwanted side effects is hypoglycemia if used with insulin.
Sitagliptin (Januvia), saxagliptin (Onglyza), and linagliptin (Tradjenta)
All are orally active drugs taken once a day, indicated in type 2 DM, they may be combined with metformin. They wont promote weight loss. Associated with only few unwanted effects. Used with precaution in patients with kidney disease. They act by protecting the breakdown of incretin, so incretins are available for long duration for insulin stimulation.
