By American Diabetes Association

The majority of medications for type 2 diabetes are oral medications, meaning they’re in pill form. Some have been around for decades, and others have recently been approved by the Food and Drug Administration (FDA). Pills for type 2 diabetes fall into nine major classes, which is just a fancy way of saying that these groups of medications work in similar ways. Within each class, there are usually generic and brand-name versions of medications in the class. You’ll also find combination pills that combine two different medications into one dose.

Ask your provider about potential side effects whenever you start taking a new medication. Then keep an eye out for these problems and call your doctor if you notice anything out of the ordinary.

Tell your provider if you’re thinking about becoming pregnant, because some type 2 diabetes medications are not recommended during pregnancy.

Supplements, including vitamins or herbal remedies, and certain foods can interfere with your medications. Over-the-counter medications can also impact prescription drugs. Tell your provider about any supplements or over-the-counter medications you’re currently taking and how you normally take them with meals.

The table lists the oral medications for type 2 diabetes.

Oral Medications for Type 2 Diabetes
Drug Class How It Works Generic Name Brand Name
Biguanides Improves sensitivity to glucose. Blocks the release of glucose from the liver. Metformin Glucophage
Sulfonylureas Stimulates your body to produce more insulin. Helps to lower your blood glucose after meals. Glimepiride Amaryl (and various generics)
Glipizide Glucotrol, Glucotrol XL (and various generics)
Glyburide Micronase, DiaBeta, Glynase PresTab (and various generics)
Meglitinides Stimulates your body to produce more insulin. Repaglinide Prandin
Nateglinide Starlix
Dipeptidyl-peptidase 4 (DPP-4) inhibitors Keeps the blood glucose–lowering hormone glucagon-like peptide-1 (GLP-1) in your body. Sitagliptin Januvia
Saxagliptin Onglyza
Linagliptin Tradjenta
Alogliptin Nesina
Sodium-glucose cotransporter 2 (SGLT2) inhibitors Blocks glucose from being reabsorbed by the kidneys. Helps your body excrete excess glucose through your urine. Canagliflozin Invokana
Dapagliflozin Farxiga
Empagliflozin Jardiance
Alpha-glucosidase inhibitors Slows the digestion of the carbohydrates you eat. Acarbose Precose (and various generics)
Miglitol Glyset (and various generics)
Thiazolidinediones (TZDs) Improves sensitivity to glucose. Pioglitazone Actos
Rosiglitazone Avandia
Bile acid sequestrants Binds to bile acids in the intestines to lower blood glucose and cholesterol. Colesevelam Welchol
Dopamine-2 agonist Lowers blood glucose in some people with type 2 diabetes. Bromocriptine Cycloset

Biguanides

Biguanides improve the body’s sensitivity to insulin and block the release of glucose from the liver. Biguanides include the most commonly prescribed medication for type 2 diabetes: metformin. Yes, you’ve probably heard this name before. There’s a reason it’s popular: It’s safe, effective, and inexpensive for many people.

Metformin is often the first medication prescribed to patients diagnosed with type 2 diabetes. And it can even be prescribed to prevent diabetes in people at risk for the disease (with a diagnosis of prediabetes).

Metformin was approved in the United States in the 1990s under the brand name Glucophage. Now, the generic form, called metformin, is readily available. You take metformin as a pill, usually two times a day. It’s also available as a liquid. Glucophage XR is an extended-release version that is also available generically.

Metformin doesn’t improve your body’s ability to make insulin, so it’s unlikely to cause episodes of low blood glucose, which is a good thing. It does have some side effects; the most common is diarrhea or loose stools. Other side effects like nausea can occur, too. Tell your healthcare provider about any side effects so she can work with you to adjust the dose or change medications.

A rare but serious side effect of metformin in certain patients is called lactic acidosis, which can cause muscle pain and weakness and other symptoms. People with severe kidney disease should not take metformin.

Ask your provider about vitamin B12 deficiency if you’ve been taking metformin for a long time. He may measure your B12 levels and, if they’re low, recommend taking a vitamin B12 supplement.

Sulfonylureas

Sulfonylureas help you make more insulin and lower your blood glucose after meals. Sulfonylureas include glimepiride (Amaryl and various generics), glipizide (Glucotrol, Gluctorol XL, and various generics), and glyburide (Micronase, DiaBeta, Glynase PresTab, and various generics).

Sulfonylureas were first approved in the 1950s, and they’re often taken once or twice a day.

Each type of sulfonylurea has different dosing, side effects, and interactions with other drugs. Sulfonylureas stimulate your body to produce insulin, so they can cause low blood glucose. Some of the most common side effects across all sulfonylureas are episodes of low blood glucose, weight gain, and skin rashes.

Meglitinides

Meglitinides help you make more insulin and lower your blood glucose. They include repaglinide (Prandin) and nateglinade (Starlix). They’re similar to sulfonylureas but faster acting.

Repaglinide was approved in 1997 and Nateglinide was approved in 2000. Meglitinides work quickly and for about 4 hours. They’re taken three times a day, just before meals.

Meglitinides can cause episodes of low blood glucose, weight gain, nausea or vomiting, and headaches.

Dipeptidyl-peptidase 4 (DPP-4) inhibitors

DPP-4 inhibitors work by keeping the “helpful hormone” GLP-1 around in your body. GLP-1 naturally lowers blood glucose, but your body breaks down GLP-1 quickly. DPP-4 inhibitors stop that breakdown and lower blood glucose. DPP-4 inhibitors include sitagliptin (Januvia), saxagliptin (Onglyza), linagliptin (Tradjenta), and alogliptin (Nesina).

Sitagliptin was the first DPP-4 inhibitor approved in the United States in 2006. DPP-4 inhibitors are usually taken once a day.

DPP-4 inhibitors can cause side effects like upper respiratory infections, sore throats, and headaches. They may also cause joint pain that is severe and disabling. And they may cause inflammation of the pancreas, which can cause gastrointestinal symptoms like pain in the abdomen, nausea, or vomiting. Tell your healthcare provider if you’ve noticed any of these side effects.

Incretins are a group of hormones that signal the body to release insulin after eating. Scientists have developed medications that target these hormones for people with type 2 diabetes. Two medications, DPP-4 inhibitors (pill) and GLP-1 agonists (injectable), work by regulating these hormones.

Sodium-glucose cotransporter 2 (SGLT2) inhibitors

Sodium-glucose cotransporter 2 (SGLT2) inhibitors work differently from the medications covered earlier. They block your kidneys from reabsorbing glucose into your bloodstream and help you excrete excess glucose through your urine. In this way, SGLT2 inhibitors lower blood glucose. They can also help you lose weight. Also, SGLT2 inhibitors could benefit patients at a high risk for cardiovascular disease. These medications include canagliflozin (Invokana), dapagliflozin (Farxiga), and empagliflozin (Jardiance).

Canagliflozin was approved in 2013; dapagliflozin and empagliflozin were approved in 2014. They’re taken once a day.

SGLT2 inhibitors can cause urinary tract and genital yeast infections and increased urination leading to dehydration. Canagliflozin and dapagliflozin carry a risk for kidney injury. In rare cases, canagliflozin causes an increased risk of leg and foot amputations, according to two large clinical trials.

Alpha-glucosidase inhibitors

Alpha-glucosidase inhibitors also work a little differently from other medications. They slow down your digestion of carbohydrates during meals and lower blood glucose. They include acarbose (Precose and various generics) and miglitol (Glyset and various generics).

Alpha-glucosidase inhibitors were approved in the mid-1990s. They’re taken three times a day at the beginning of each meal.

Side effects include gas, stomach pain, and diarrhea. They can also contribute to episodes of low blood glucose, and because these medications can slow the breakdown of sugars such as fruit juice, always use a glucose product such as glucose gel to treat symptoms of hypoglycemia.

Thiazolidinediones (TZDs)

Thiazolidinediones (TZDs) make you more sensitive to insulin and lower blood glucose. They include pioglitazone (Actos) and rosiglitazone (Avandia).

TZDs were approved in the late 1990s. They’re taken once or twice a day.

Side effects of TZDs have made them less commonly prescribed, particularly rosiglitazone. In 2010, the FDA imposed restrictions for prescribing rosiglitazone because of concern over increased cardiovascular risk, although those restrictions were lifted in 2013. Rosiglitazone may also increase the risk of bone fractures. Pioglitazone may increase the risk of bladder cancer; people with a history of bladder cancer should not use it. Other side effects include headache, sore throat, and back pain.

Bile acid sequestrants

Bile acid sequestrants bind to bile acids in the intestinal tract and lower blood glucose and cholesterol. There is one with FDA approval called colesevelam (Welchol).

Side effects include gas, constipation, nausea, diarrhea, stomach pain, and weakness or muscle pain.

Dopamine-2 agonists

Dopamine-2 agonists lower blood glucose in some people with type 2 diabetes, although how they work is unclear. One medication, bromocriptine (Cycloset), is FDA approved for this use.

Side effects include dizziness, nausea, and fatigue.

Combination pills for type 2 diabetes

Your provider may recommend a combination pill if your body needs more help lowering blood glucose. A combination pill is handy because you only need to take one, versus two or more pills, at a time. Some common examples of combination pills include

  • Metformin and glipizide (Metaglip)
  • Metformin and glyburide (Glucovance)
  • Metformin and sitagliptin (Janumet and Janumet XR)
  • Metformin and linagliptin (Jentadueto and Jentadueto XR)
  • Metformin and repaglinide (Prandimet)
  • Metformin, extended release, and saxagliptin (Kombiglyze XR)
  • Metformin and alogliptin (Kazano)
  • Metformin, extended release, and dapagliflozin (Xigduo XR)
  • Metformin and canagliflozin (Invokamet and Invokamet XR)
  • Metformin and empagliflozin (Synjardy and Synjardy XR)
  • Metformin and pioglitazone (ActosPlus Met and ActosPlus Met XR)
  • Metformin and rosiglitazone (Avandamet)
  • Dapagliflozin and saxagliptin (Qtern)
  • Empagliflozin and linagliptin (Glyxambi)
  • Glimepiride and pioglitazone (Duetact)
  • Glimepiride and rosiglitazone (Avandaryl)
  • Alogliptin and pioglitazone (Oseni)