Type 2 medications for adults with type 1 diabetes

Type 1 diabetes is so different from type 2 that you might wonder how type 2 diabetes medications could benefit you. But some of you might already be using one or more of these medications. The medications discussed in this article are for adults only.

Type 2 medications being prescribed for type 1 diabetes

Metformin, sodium-glucose cotransporter inhibitors (SGLT2i’s) and glucagon-like peptide-1 agonists (GLP-1 agonists) are all used in type 1 diabetes. They don’t replace insulin; however, they can help you manage your health living with type 1 diabetes.


A recent study compared 29 adults living with type 1 diabetes taking metformin to a matched group of people not taking metformin. The results showed that metformin decreased glucose concentrations, reduced metabolic syndrome, and insulin dose requirement more than insulin therapy alone, one year after treatment. (1)

In summary, those that took metformin found:

Less insulin was required Bodyweight did not increase No extra hypoglycaemia 17% gastrointestinal discomfort

Metformin is an oral glucose-lowering medication. Brand names include Metformin XR, Diabex, Diaformin, Metex and Formet.

It increases insulin sensitivity in the liver and muscles. Less insulin is required to do the same job.

In the liver, metformin decreases the release of glucose from storage. This means less insulin is required overnight. In muscles and fat cells, metformin increases glucose uptake. In this way, it improves the way insulin works when injected. Metformin leads to a reduction in the amount of insulin needed and reduces weight gain.

If you are a person that struggles to gain or maintain weight, metformin will not benefit you.

GLP-1 agonists

You have cells in the small and large intestine that release hormones in the bloodstream when you eat. These hormones are called incretins, specifically GLP-1 and GIP.

The natural incretin hormones break down very quickly and easily; however, they have the action of stimulating the beta cells to release more insulin, slow the gut motion and produce a feeling of fullness. Better action comes from the GLP-1 hormone, so medications are used to increase this action by reducing the breakdown of the naturally produced hormone or mimicking GLP-1.

In type 1 diabetes, you will have little to no beta cells producing and releasing insulin. Therefore, the medications cannot help this particular action for you.

However, slowing the gut motion and making you feel fuller for longer may assist you with managing your blood glucose levels and losing weight if you are above your recommended weight range.

DPP4 inhibitors not helpful with type 1

The medications which slow the breakdown of naturally produced incretins are called gliptins or DPP4 inhibitors. These are orally administered medications. Unfortunately, these medications are not helpful in type 1 diabetes.

The newer medications which mimic GLP-1 are injectable. These medications resist natural breakdown in the body and can have an action of several weeks. Those available in Australia include:

Brand name Active ingredient How often injected
Byetta Exenatide Twice a day before meals
Victoza, Saxenda Liraglutide Daily
Trulicity Dulaglutide Weekly
Ozempic Semaglutide Weekly

An analysis of several studies of people using GLP-1 agonist medications living with type 1 diabetes revealed:

Nausea and vomiting are side-effects that reduce with time GLP-1 agonists improved HbA1c Lowered body weight Did not increase the risk of hypoglycaemia Results were only noticed after 12 weeks of treatment Less insulin was required

Liraglutide (1.8mg) may increase the risk of high blood glucose levels with ketones so if you use it make sure you have in-date ketone strips available.

GLP-1 agonists may suit you if you are above your ideal weight and an adult. GLP-1 agonists will not be suitable for you if you are underweight, have gastroparesis or have any gut issues. (2)

SGLT-2 inhibitors

When your blood glucose rises above 10 mmol/L, your body releases the extra glucose through your urine. Your kidneys work to get rid of the waste while retaining important nutrients. You have a filtering system in your kidneys that retains glucose; however, it becomes overwhelmed with high blood glucose. It is like damming a river; once the water level rises above the dam wall, water overflows.

SGLT-2 inhibitors lower the glucose level at which glucose flows into the urine, like lowering the dam wall.

As a result, glucose is always overflowing into the urine, and blood glucose levels are lower. Because you lose glucose, water is dragged along and promotes urination. This action may lower blood pressure (as it would taking a diuretic); however, it can be dehydrating and increase the rate of urinary tract infections.

Those available on the Australian market are:

Brand name Active ingredient
Jardiance Empagliflozin
Forxiga Dapagliflozin
Steglatro Ertugliflozin

SGLT-2 inhibitors are used successfully in type 2 diabetes.

In type 1 diabetes, SGLT2 inhibitors can:

Reduce HbA1c Smooth out your glucose levels


Do not increase hypo risk Lower your insulin total daily dose Reduce your risk of heart conditions Reduce the damage to your kidneys with diabetes
Increase your risk of bladder infections Increase your risk of genital infections Increases the risk of diabetic ketoacidosis Reduce your blood pressure Decrease body weight by 2-3kg Increase your risk of dehydration

Risk of diabetic ketoacidosis

The main risk of using SGLT-2 inhibitors is diabetic ketoacidosis (DKA).

This risk is due to the reduction in the need for insulin and is generally only an issue in certain circumstances.

Insulin helps your body to use the glucose from your food and stops the breakdown of fat from your body stores. The breakdown of fat stores in your body produces ketones. When blood glucose is lower you will need less insulin. Not having enough circulating insulin switches your energy source from glucose to fat stores.

The overproduction of ketones can happen with SGLT 2 inhibitors at glucose levels within your target range. This is more likely if you haven’t eaten sufficient carbohydrates, are dehydrated, have an infection, illness or are physically stressed.

Reasons for stopping SGLT-2 inhibitors

For these reasons, SGLT-2 inhibitors are stopped if you are fasting, ill or going into hospital for an operation. (3)

The benefits to your health ongoing must be weighed against risks, similar to any medications.

Finally, please discuss and carefully consider using these medications with your doctor or endocrinologist. For more information on this topic or general inquiries, please contact the NDSS Helpline on 1800 637 700 or info@diabetesqld.org.au.


  1. The effects of metformin in type 1 diabetes mellitus. Beysel, S., Unsal, I. O., Kizilgul, M., Caliskan, M., Ucan, B., & Cakal, E. 1, January 16th, 2018, BMC endocrine disorders, Vol. 18.
  2. Incretin-based therapies for patients with type 1 diabetes: a meta-analysis. Liu, L, et al. 3, 2019, Endocrine connections, Vol. 8, pp. 277-288.
  3. Beyond Type 2 diabetes: sodium-glucose co-transporter-inhibition in type 1 diabetes. Blester, T, Kordonouri, O and Danne, T. 2, May 13th, 2019, diabetes, obesity and metabolism, Vol. 21, pp. 53-61.


By Donna Itzstein – Pharmacist, CDE

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