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Diabetes drugs

Below please find an overview of the most commonly used drugs for type 1 and type 2 diabetes. Click each drug class’ link to learn more information, including a list of the currently approved drugs in each class and the pros and cons of each type.


Metformin – Metformin decreases glucose production from the liver, thus lowering blood sugar. Recent evidence suggests that metformin has some glucose-lowering action directly via the intestine.    

DPP-4 inhibitors – Inhibiting the enzyme DPP-4 increases the level of a hormone named GLP-1, which stimulates insulin production and decreases production of glucagon (insulin’s “opposite” hormone) when glucose levels are too high. 

SGLT-2 inhibitors – SGLT-2 inhibitors are a new class of glucose-lowering drugs that cause the kidneys to excrete excess glucose through the urine. They are a unique drug class in that they work independently of insulin.

Combination drugs – Combination therapies put multiple drug classes into a single medication. Combinations can be injectable (i.e. GLP-1 agonists with basal insulin in a single injection) or “fixed-dose combination” tablets that can be taken orally (i.e. metformin combined with an SGLT-2 inhibitor into a single pill). Typically, they are meant to improve efficacy and potentially reduce side effects compared to taking multiple drugs separately. It also increases convenience for patients and has the potential to decrease co-pays for multiple medications.

TZDs – TZDs activate a protein that regulates genes involved in making and using fats, with the net result of decreasing insulin resistance. Insulin resistance, or the inability of cells in the body to respond appropriately to insulin by removing glucose from the blood, is one of the underlying problems of type 2 diabetes.

Sulfonylureas – Sulfonylureas continuously stimulate the release of insulin from the pancreas. However, there are significant risks of hypoglycemia and weight gain from taking sulfonylureas and there is concern that they may overwork the pancreas, thereby quickening the progression of type 2 diabetes. 


Injected Insulin – Insulin is a hormone produced by the pancreas that stimulates cells in the body to remove glucose from the blood for storage or usage. Normally, insulin is released when the body has high amounts of sugar in the blood, such as after a meal, to bring levels back into a normal range.

Inhaled Insulin – Inhaled insulin works through the same mechanism as injectable insulin, but it is taken with an oral inhaler rather than through an injection or a pump. The only approved inhaled insulin that is on the market is MannKind’s ultra-rapid-acting inhaled insulin Afrezza.

GLP-1 agonists – GLP-1 is a hormone produced in the small intestine that stimulates insulin secretion and inhibits glucagon secretion, thereby lowering blood sugar. Shorter-acting agonists of the GLP-1 receptor are particularly effective at lowering post-meal glucose spikes, whereas longer-acting GLP-1 agonists have more balanced effects on lowering post-meal and fasting glucose levels.

*Please note, this page is not a comprehensive list of all of the available diabetes drugs.