Pharmacology - Diabetes Medication

Hello in this video we're going to talk about the medications used in diabetes type 2. This is a pharmacology video and it's an overview. So before we start I'm just going to draw a general diagram, a mind map so we can get our heads around the different drugs used in diabetes type 2. So here is the stomach, here is the bloodstream and here we have the pancreas. Now the pancreas is made up of different types of cells, one of which are these cells known as B cells and these B cells are the ones that produce the hormone insulin. Alright we'll get back to this and here is the liver, adipose tissue which store fat and here's the skeletal muscles which actually use glucose as a source of energy. So let's look at what normally happens. So after we eat a meal there is an increase in blood glucose. The glucose gets absorbed in the blood. Now with the increase in blood glucose this will actually stimulate the B cells in the pancreas to release the hormone insulin. So the insulin vesicles from the B cells are being released into the bloodstream. Insulin enters the bloodstream where it causes its physiological functions which includes going to the liver, stimulating glucose uptake in the liver as well as stimulating glucose uptake in skeletal muscle. So I hope that made sense. Insulin essentially functions by trying to lower blood glucose by making glucose get taken up by these different tissues. Diabetes myelitis is characterized by insulin resistance. So the effects of insulin on body tissues doesn't work properly. So the insulin cannot stimulate glucose uptake to tissues from the blood and as a result you have a sort of persistent high blood glucose. Increase in blood glucose with insulin resistance will eventually lead to B cell atrophy, B cell failure which makes the whole problem a lot worse and because of this it is important to treat patients with diabetes. Obviously initially with non-pharmaceutical interventions such as diet and exercise but medications are useful for patients with diabetes and include insulin subcutaneous injections but these are typically seen for patients with type 1 diabetes but can also be seen in some patients with serious type 2 when there is B cell atrophy and death. Now the actual pharmacological medication that we'll firstly talk about is a biguanide and a good example is metformin. And metformin is a first-line treatment for patients with diabetes type 2 and essentially what they do is that they will cause an increase in insulin sensitivity, they will increase glucose uptake in tissues as well as decreasing glycogenolysis. So here in the liver insulin stimulates glucose moving into the cell and essentially it will also stimulate glucose to store as glycogen. Metformin also inhibits the actual breakdown of glycogen to glucose so that the glucose is not released into the blood. The side effects of metformin include mainly gastrointestinal upset, anorexia and a very important condition lactic acidosis. Contradictions are for those who have liver and renal dysfunction so you don't use metformin for these patients or you have to be weary. The next pharmacological medications are insulin secretogogues such as sulfonylurea. Now these guys stimulate essentially B cells in the pancreas to release insulin. So insulin secretogogues such as sulfonylurea these guys basically force the B cells to pump out insulin. Sulfonylurea does this by inhibiting the potassium transporter preventing the efflux of potassium causing depolarization of the B cells which will then lead to the release of insulin from the vesicles. The side effects of insulin secretogogues include hypoglycemia and weight gain. The next medication are insulin sensitizers and examples of these include, and I'm going to pronounce this wrong, it's theazolidin dione and they work by increasing insulin sensitivity as well as decreasing free fatty acid release. They inhibit the release of free fatty acids from adipose tissue as well they stimulate as mentioned insulin sensitivity which essentially will lead to increasing glucose uptake to tissues and decrease in glucose release into the bloodstream. Side effects of insulin sensitizers include anemia, congestive heart failure, peripheral edema, fracture and so therefore insulin sensitizers are contraindicated in patients with congestive heart failure and liver failure. The next medications work on the small intestine so let us zoom into this area here where glucose is absorbed into the bloodstream. Here is the lumen and here are the epithelial cells of the intestine. In the lumen there are short carbohydrate molecules that are being broken down into the macromolecule glucose. Glucose is what is being absorbed and enters the bloods. The enzyme responsible for the final breakdown of carbohydrates especially disaccharides in the small intestines are these enzymes, brush border enzymes called glucosidase and these are present on the apical surface of the small intestinal cells and so there is a drug called alpha glucosidase inhibitors such as A-carbose and these guys literally inhibit this enzyme causing a decrease in glucose absorption and thus decreasing blood glucose. Side effects of glucosidase inhibitors include flatulence, cramps and diarrhea. This medication is contraindicated for patients who have inflammatory bowel disease. The final medication for diabetes myelitis type 2 are ones that work like a hormone produced by the intestinal cells called GLP-1. Now GLP-1 actually normally stimulates B cells in the pancreas to release insulin and so these groups of medications are actually GLP-1 analogs and GLP-1 analogs bind to GLP-1 receptors causing an increase in insulin release and thus they essentially mimic the effects of GLP-1. Side effects of these medications include headaches, muscle weakness and contraindications include type 1 diabetes myelitis and diabetic ketoacidosis.