Overview of Medications for Type 2 Diabetes

Dr. Loren Grossman, MD, FRCPC, FACP, Endocrinologist, goes over the first line and second line medications available today for the treatment of diabetes.

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Dr. Loren Grossman, MD, FRCPC, FACP, Endocrinologist, goes over the first line and second line medications available today for the treatment of diabetes.
Video transcript

Featuring Dr. Loren Grossman, MD, FRCPC, FACP, Endocrinologist

Duration: 5 minutes, 51 seconds

Diabetes is a very complicated disease. The first treatment that was discovered in the 1920s was insulin, and that was a lifesaver for type 1 diabetes. But for type 2 diabetes, we’ve had a number of other medications since about the 1950s or 60s with metformin and typically the sulfonylureas as second choice.

The problem with those is there are a number of drawbacks to those medications and side effects, so the development of newer medications is very welcome. The first new class that we had is a very long name, the TZDs, or the thiazolidinediones, particularly like pioglitazone and rosiglitazone. And they helped with the treatment of diabetes but they themselves had some problems, with one coming off the market and side effects.

Fortunately in the past five, ten years we’ve had a number of different medications that have been developed for the treatment of type 2 diabetes. These can include the DPP-4 inhibitors, that are used for second-line treatment for diabetes. There’s also what are called the sodium-glucose cotransporter-2 inhibitors, or SGLT-2 inhibitors. And we now have injectable medications, the GLP-1 or the glucagon-like protein one agonists.

Each one of these classes has their own number of medications, and each class has its own pluses and minuses for the treatment of type 2 diabetes. Generally speaking, and according to the Canadian Diabetes Association Clinical Practice Guidelines—and other international guidelines—metformin remains the first drug of choice for the treatment of diabetes. Unless of course the patient urgently needs insulin, if they are in metabolic decompensation or severe symptoms of hyperglycemia. But putting that group aside, metformin remains first choice. The guidelines then recommend individualizing our choice for second choice medication, depending on the individual patient’s needs. And here’s where the different classes of the medications come in.

For example, DPP-4 inhibitors are an excellent second choice for patients who are slightly above target, and need a little extra to get down to their target A1C. They tend to have minimal side effects, mostly gastrointestinal, but they’re also not as efficacious, and you can expect maybe a half a percentage point or so reduction in the A1C.

When not to use them would be if certain side effects occur, particularly there has been some concern about pancreatitis, and therefore if a patient has a history of pancreatitis I tend to avoid that class of medication.

SGLT-2 inhibitors work by a different mechanism. They tend to promote some weight loss and lower blood sugars to a greater degree—to maybe up to almost one percent sometimes or even more. And therefore if you have a patient who is not doing well with metformin alone, who has a significant amount of weight to lose, an SGLT-2 inhibitor would also be an excellent choice.

The other thing to keep in mind is that this class of medication has recently been shown to be a benefit in cardiovascular outcomes. And therefore, if a patient has either a history of cardiovascular disease or is at high risk, then that would be a good second choice as well.

Recent data has also suggested some of these medications can also improve patients who have mild to moderate chronic renal failure, and therefore this might be an appropriate second choice as well. Side effects to keep in mind is there will be increased urination and thirst, patients need to worry about this medication if they can’t take in oral fluids with a concurrent illness, and there is an increased risk of mycotic infection, so if that’s been an issue that may be one to avoid.

Going to injectable medications, GLP-1 agonist, the glucagon-like peptide one agonist, are an excellent choice again, for some weight loss, and they’ve also been shown to reduce cardiovascular events, so if you have a patient who has, again, cardiovascular disease, or is at high risk, and needs to lose significant weight, this may also be an excellent choice if a patient is willing to take an injectable medication.

We used to have medications that were injected on a daily basis, but now there are newer formulations that have come out that can be injected once a week. And we often find that a weekly injection is much more tolerable, and the patients are much more amenable to doing that, than a daily injection. As well, there are some newer formulations under development for the oral formulations of GLP-1, so that may be something to look at in the future.

To summarize all this, if a patient needs urgent, quick diabetes control because of metabolic decompensation or severe symptoms, they need to take insulin. For the others, metformin remains first-line therapy, unless there are contraindications, and then if patients are failing on the first-line therapy of metformin, there are a host of other options which need to be individualized to the patient’s needs, based upon individual needs, plus or minus the side effect profile.

For more information, patients should speak to their family doctor, or speak to their diabetes nurse educator or endocrinologist.

Presenter: Dr. Loren Grossman, Endocrinologist, Toronto, ON

Local Practitioners: Endocrinologist

Quiz: Do You Understand Overview of Medications for Type 2 Diabetes? ( 1 participated.)

Test your knowledge by answering the following questions:


Insulin was discovered in the 1920s.


DPP-4 inhibitors are used for second-line treatment for diabetes.


DPP-4 inhibitors are fine if a patient has a history of pancreatitis.


SGLT-2 inhibitors tend to promote weight gain.


There are newer medications that have come out that can be injected once a week.

This content is for informational purposes only, and is not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified healthcare professional with any questions you may have regarding a medical condition.

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