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If you’re experiencing type 2 diabetes symptoms, there are a variety of oral medications your healthcare provider may prescribe for you. The meds may work as single therapy, in combination with insulin, or in combination with another oral medication.
Each group of drugs has a unique mode of action, but the net effect of each is to lower blood sugar levels.
- Biguanides: Biguanides are a group of drugs that decrease the amount of glucose released from the liver. The most commonly prescribed oral medication for type 2 diabetes symptoms, metformin, is a biguanide.
- Thiazolidinediones: Thiazolidinediones, like biguanides, help reduce glucose release from the liver but also enhance insulin’s effect in fat and muscle tissue. The two thiazolidinediones on the market as of October 2015 are pioglitazone (ACTOS) and rosiglitazone (Avandia). Rosiglitazone has been linked in some studies to an increased risk of heart attacks and heart failure and is under review by the FDA but has not yet been pulled off the market.
- Sulfonylureas: Sulfonylureas work by stimulating the beta cells of the pancreas to secrete more insulin. There are first and second generation sulfonylureas. The only first generation sulfonylurea still prescribed is Chlorpropamide (Diabinese). The second generation sulfonylureas are glipizide (Glucotrol and and Glucotrol XL), glyburide (Diabeta, Micronase), and glimepride (Amaryl).
- Meglinitides: Meglinitides also stimulate the pancreas to secrete more insulin. Repaglinide (Prandin) and nateglinide (Starlix) are the meglinitides available today.
- DPP-4 inhibitors: Our intestinal cells produce a hormone called glucagon-like peptide-1 or GLP-1. GLP-1 promotes insulin secretion from the beta cells and also lowers the amount of glucose produced by the body. Some evidence suggests that it might also promote beta cell proliferation. GLP-1, however, is quickly broken down in our bodies by an enzyme called DDP-4. DDP-4 inhibitors, like sitagliptin (Januvia), saxagliptin (Onglyza), linagliptin (Tradjenta), and alogliptin (Nesina), block the action of this enzyme, thereby allowing GLP-1 to remain active longer, and ultimately aid in lowering blood sugar levels.
- SGLT-2 inhibitors: As blood is filtered through our kidneys, a molecule called sodium-glucose transporter 2 (SGLT-2) promotes reabsorption of glucose back into the blood. SGLT-2 inhibitors like canagliflozin (Invokana) and dapagliflozin (Farxiga) block the action of SGLT-2, thereby allowing the elimination of excess glucose into the urine and the lowering of blood glucose levels.
- Alpha-glucosidase inhibitors: Alpha-glucosidase inhibitors like acarbose (Precose) and miglitol (Glyset) work by slowing the breakdown of some carbohydrates (a source of glucose) in our intestines.
- Bile acid sequestrants: These drugs were initially used just to lower cholesterol levels, particularly LDL levels. Although it is not clearly understood why, researchers have found that they also lower glucose levels.
- Bromocryptine mesylate: This drug helps to increase the levels of the neurotransmitter dopamine. Although the mechanism is poorly understood, dopamine appears to have a positive effect on glycemic control.
Because many of these groups of drugs work differently to lower blood sugar combining different classes can be a more effective way to manage some people’s type 2 diabetes symptoms. A number of formulations containing more than one drug are available. Your healthcare provider will work to determine the best combination for you, bearing in mind side effects and drug interactions.
Originally published in April 2016 and updated.