Diabetes Medications

As most people with diabetes know well, wildly fluctuating levels of sugar in the bloodstream can cause trouble. High levels of blood sugar, due to a lack of insulin or resistance to insulin, reflect the body’s inability to transport sugar into its cells to be used as fuel. The cells literally begin starving to death — a process that can lead to kidney disease, heart disease, chronic infections, and a host of other ailments. But with proper treatment, patients with diabetes can bring their blood sugar under control. While some people can achieve that control through diet and exercise, many will need extra help. Thanks to modern medicine, help isn’t hard to find.

Doctors who treat diabetes can choose from a long list of effective medications, including some that have just hit the market. When taken properly, diabetes medications can lower your blood sugar level, reduce your symptoms, and lessen your risk of diabetic complications, such as nerve damage and vision loss. Remember though, that no matter what diabetes drugs you take, it’s still crucial to get regular exercise and follow a meal plan.

Here’s an overview of currently available treatments:


Insulin, a natural hormone, is essential to clear the sugar (glucose) from the foods you eat from your bloodstream and distribute it throughout the cells of your body. It also helps your body convert that sugar into energy. Since people with type 1 diabetes are unable to make the hormone on their own, they need regular doses of insulin — either injected multiple times per day or delivered through an implanted pump.

Injections of insulin are also an effective weapon against type 2 diabetes. Insulin may be prescribed as a first-line defense, but it’s most often used when oral drugs fail to do the job. Your doctor will work with you to come up with the most effective drug regimen for yourself.

Commonly, a shot of insulin at bedtime is combined with an oral drug during the day. Insulin comes in many different forms. Some act quickly, while others take longer to kick in. A newer form of insulin (Afrezza) became available in 2015. It can be inhaled rather than injected, but is not recommended for people with chronic lung disease. Your doctor may prescribe a combination of insulins to give you maximum control.

Whatever kind of insulin you take, you’ll have to carefully time your injections and closely monitor your blood sugar to avoid hypoglycemia (low blood sugar) and hyperglycemia (high blood sugar).

Here’s a quick look at the different types of insulin:

Regular insulin lowers blood sugar in 30 minutes after a subcutaneous injection and lasts for five to seven hours. The peak effect is at two and a half to five hours. Examples include Humulin R and Novolin R.

Humalog (Insulin lispro) is a genetically engineered, quick-acting compound that starts lowering blood sugar within 15 minutes of subcutaneous injection, peaks in about 30-90 minutes and keeps working for three to five hours. This type of insulin is injected within 15 minutes before or right after a meal (compared with 30 minutes for regular insulin), allowing for greater flexibility. However, it may have to be injected more often than regular insulin.

Humulin N, Novolin N (NPH) are intermediate-acting insulins. They start working in one to four hours, reach a peak between four and 14 hours, and last quite a bit longer than regular insulin or Humalog, from 10 to 24 hours. These intermediate-acting insulins have replaced lente insulin, which is no longer available in the United States because of its limited use.

Lantus (insulin glargine) lasts for 24 hours and unlike other forms of insulin, it works steadily throughout the day without any pronounced peaks. This may reduce the risk of hypoglycemia. The glucose-lowering activity of the drug begins in one and a half hours after subcutaneous injection.

Levemir (insulin detemir), like Lantus, is another long-acting insulin that doesn’t peak but works evenly over a 5- to 24-hour period. Approved by the FDA in 2005, it takes several hours for the drug to begin working.

Afrezza is an inhaled insulin that has been available since 2015. Some Afrezza users have found that the drug is as effective as injected forms of the drug and is easier to use.

Oral medications

If you have type 2 diabetes, your doctor may prescribe an oral drug to control your blood sugar. Many of these drugs affect insulin, which clears sugar from the blood. Some increase the production of insulin, while others increase your body’s sensitivity to the insulin that’s already there. (Because people with type 1 diabetes make little or no insulin, they won’t benefit from these medications.) If your blood sugar is still too high, your doctor may prescribe a combination of drugs.

No single type of medication works best for all patients. Your doctor will choose a drug that fits your particular needs. (It’s important to let the doctor know if you are pregnant or taking other medications or herbs, which might interact with your new medications.) Whichever drug (or drug combination) is prescribed, follow the instructions to the letter, and be sure to ask your doctor about potential side effects.

You can find out how your medication is working by checking your blood glucose (sugar) at the times outlined by your doctor or health care provider. If your blood glucose or HbAlc is within the target range most of the time, your medicine regimen is working. If not, contact your physician or provider.

Oral medications for diabetes come in several different classes. Below are examples of some of the more common medications in use today:


In use for the last 40 years, sulfonylureas treat type 2 diabetes when nutrition and exercise alone aren’t enough to control blood sugar. They increase the production of insulin and help your body make use of the hormone. Here are some drugs included in this category:


Glimepiride — Amaryl

Glipizide — Glucotrol

Glyburide — DiaBeta, Micronase

Possible side effects of these drugs include hypoglycemia (low blood sugar), upset stomach, rarely weight gain, and allergic reactions in people who have an allergy to sulfa medicines.


Biguanides improve glucose tolerance and decrease the amount of glucose made by your liver.


Metformin — Glucophage, Fortamet, Glucophage XR

This medicine is less likely to cause hypoglycemia when compared to sulfonylureas, but it can cause diarrhea, nausea, vomiting, and abdominal discomfort especially when taken on an empty stomach.

Alpha-glucosidase inhibitors

These drugs slow down the absorption of sugar into the blood and make you more sensitive to insulin. They are often used in combination with other diabetes medications.


Acarbose — Precose

Miglitol — Glyset

Alpha-glucosidase inhibitors are taken with meals. Common side effects include gastrointestinal distress, including gas and diarrhea. Let your physician know if these symptoms persist more than a few weeks. Sometimes these problems can be avoided by beginning with a lower dose and increasing it gradually. People with severe bowel or kidney disease or liver disorders should not take this medication.


This type of medication makes your cells more sensitive to insulin and decreases the amount of glucose secreted by the liver. It is sometimes given in combination with metformin (see Biguanides, above).


Pioglitazone — Actos

Possible liver problems are a concern with these drugs. It is important for your doctor to check your liver regularly if you take thiazolidinediones. These drugs may also cause weight gain, edema, and swelling. If you experience unusual nausea, vomiting, abdominal pain, severe fatigue, or dark urine, call your doctor immediately. One drug of this type, troglitazone, was withdrawn from the market in the fall of 2000.

In September 2010, the Food and Drug Administration severely restricted the use of another drug for type 2 diabetes, Avandia, because controlled clinical trials showed a significant increase in heart attack risk and death for patients using the drug. The FDA lifted most of those restrictions on the controversial drug in 2013, citing some weaknesses of the earlier clinical trials, but many doctors prefer to prescribe other drugs for people with type 2 diabetes.


This type of drug stimulates the pancreas to produce more insulin. Glinides are fast acting and short-lived, allowing greater flexibility in meal timing.


Repaglinide — Prandin

Nateglinide — Starlix

When taken with meals, these drugs decrease the risk of hypoglycemia. Glinides act similarly to sulfonylureas in the way they control blood sugar, but in clinical studies repaglinide appears to be more potent than nateglinide.


A single pill that combines a biguanide with a sulfonylurea (Glucovance) or a biguanide with a thiazolidinedione (ActoPlus Met, Avandamet) can increase the effectiveness of insulin using different mechanisms in the body. Biguanides decrease insulin production through the liver, sulfonylureas increase insulin production through the pancreas, and thiazolidinediones increase overall insulin sensitivity.


Glyburide and metformin — Glucovance

Pioglitazone and metformin — ActoPlus Met

Rosiglitazone and metformin — Avandamet

Glucovance is approved for use by people with type 2 diabetes and is generally well tolerated. With Glucovance, some patients develop hypoglycemia but the episodes are mostly mild. Some patients develop mild diarrhea or an upset stomach, but this usually goes away in a few weeks; very rarely, patients may develop increased sensitivity to the sun. However, Glucovance shouldn’t be taken by anyone with kidney disease or a history of liver disease, who drinks heavily, or who has a serious condition such as a severe infection.

Nausea, diarrhea, and headache are the most common side effects for people taking Avandamet. Chest infection, diarrhea, and nausea are common side effects with ActoPlus Met. Both Avandamet and ActoPlus Met have FDA boxed warnings and may cause or worsen heart failure. People with type 1 diabetes, children, and pregnant women should not use either of these drugs.

Another class of drugs — SGLT2 inhibitors — have recently been approved for type 2 diabetes. These drugs — Farxiga (dapaglifozin) and Involcana (canaglifozin) works by helping block the kidneys’ absorption of sugar, so less is absorbed by the body.

Further Resources

American Diabetes Association 800/342-2382 

National Institutes of Health, National Institute of Diabetes, Digestive and Kidney Disease


Fujimoto WY. Background and recruitment data for the U.S. Diabetes Prevention Program. Diabetes Care. Vol. 23 Suppl 2:B11-3.

The Diabetes Monitor: Troglitazone. Warner-Lambert voluntarily withdraws Rezulin. http://www.diabetesmonitor.com/rezulin.htm. Also: http://www.warner-lambert.com/press/release.asp?release=109

All our patients need to know about intensified diabetes management they learned in fourth grade. Diabetes Educ. Vol. 26(3):392-4, 396, 400-2 passim.

Food and Drug Administration. FDA Consumer. Insulin Key to Diabetes But Not Full Cure. http://www.fda.gov/bbs/topics/CONSUMER/CON00137.html

About Insulin. American Diabetes Association. http://www.diabetes.org/type-2-diabetes/insulin.jsp

American Diabetes Association. Diabetes forecast. http://www.diabetes.org/uedocuments/rg05insulins.pdf

Food and Drug Administration. FDA Approves First Ever Inhaled Insulin Combination Product for Treatment of Diabetes. http://www.fda.gov/bbs/topics/news/2006/NEw01304.html

Food and Drug Administration. FDA Issues Safety Alert on Avandia. http://www.fda.gov/bbs/topics/NEWS/2007/NEW01636.html

Clinical Pharmacology Online Drug Monographs. GoldStandard.

Food and Drug Administration. Patient Information Sheet: Insulin Detemir (rDNA origin) Injection (marketed as Levemir). http://www.fda.gov/cder/consumerinfo/druginfo/Levemir.htm

American Association of Clinical Endocrinologists. Medical guidelines for clinical practice for the management of diabetes mellitus. Endocrine Practice. Volume 13 (Supp 1).

Food and Drug Administration. Avandamet. http://www.fda.gov/cder/foi/label/2008/021410s025lbl.pdf

Food and Drug Administration. Pioglitazone HCI Information for Healthcare Professionals. http://www.fda.gov/CDER/Drug/InfoSheets/HCP/pioglitazoneHCP.htm

Food and Drug Adminstration. ActoPlus Met. http://www.fda.gov/cder/foi/label/2009/021842s007lbl.pdf

Rosenstock J, et al. Prandial inhaled insulin plus basal insulin glargine versus twice daily biaspart insulin for type 2 diabetes: a multicentre randomised trial. The Lancet. Vol. 375, Issue 9733 http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(10)60632-0/abstract

“FDA affirms safety of diabetes drug Avandia; clears it for widespread use,” Los Angeles Times, Nov. 2013.

Sanofi and MannKind Announce Afrezza®,the Only Inhaled Insulin, Now Available in the U.S. http://en.sanofi.com/Images/38264_20150203_Afrezza_en.pdf

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