Common questions about diabetes medicines

Patient and care provider discuss medicines

How do I know if my diabetes pill is working?

The best way to find out how well your diabetes pill is working is to check your blood sugar. Ask a member of your health care team what time of day is best for checking. You'll want to check when your diabetes medicine is expected to be most active in your body. Keep a record of your blood sugar levels (PDF) during that time to see if they're at or near your goal.

If your levels are at or near your goal and you're not having any problems with the medicine, then it's probably working well. If you're still not sure, talk to your doctor or other member of your care team.

Can I stop taking my diabetes medicine after my blood sugar is under control?

It's reasonable to think that after a person gets blood sugars in their target range, it means the end of managing diabetes. But that's not the case.
People with type 1 diabetes aren't able to make their own insulin, so they will always need to take insulin shots every day.

For people with type 2 diabetes who are on medicine, the answer isn't as clear. Sometimes when people are first diagnosed, they start on pills or insulin right away, especially if the diagnosis comes at the same time as another illness. If that person’s body responds well to lifestyle intervention, and recovers from the illness, they may be able to lower their medication, or may be able to stop taking it altogether. You should not lower your medication on your own. Work with your doctor or other member of your healthcare team before decreasing or discontinuing your medications.

However, type 2 diabetes changes over time. The change can be fast or slow, but it does change. This means that even if a person was able to stop taking medicine for a while, they might need to start taking it again in the future. If a person is taking medicine to keep blood sugar within target, then it's important to keep taking it to lower the chances for heart disease and other health problems that can result from blood sugars that above target. Also, sometimes when a person’s blood sugar has been controlled on pills for an extended period of time, their sugar levels may eventually rise requiring them to need insulin as well.

What's the difference between generic and brand name medicines?

The generic name is the name of the medicine's chemical makeup. The brand name is the name that the company who makes the medicine uses to advertise and sell the drug. For example, metformin comes from a class of drugs called biguanides. The company that introduced this drug in the United States sells it under the brand name Glucophage.

What about some of the newer drugs?

There are two fairly new categories of drugs that many people have heard and have questions about. These are Glucagon-like Polypeptide-1 (GLP-1) and Dipeptidyl Peptidase IV (DPP-4) inhibitors.

Glucagon-like Polypeptide-1 (GLP-1) agonists are taken as a daily or weekly shot. Three of the drugs in this category are exenatide (Bydureon), liraglutide (Victoza), and semaglutide (Ozempic).

Dipeptidyl Peptidase 4 (DPP-4) inhibitors were first introduced in 2006 for the treatment of type 2 diabetes. They can be used alone or in combination with other oral diabetes medicine. Three examples of drugs in this category are linagliptin (Tradjenta), sitagliptin (Januvia) and saxagliptin (Onglyza).

Both the GLP-1 and DPP-4 medications tell the pancreas to release more insulin when blood sugar is high. They also slow down digestion and decrease appetite. There is very little risk for hypoglycemia with these drugs unless used in combination with insulin or other medications. Although these drugs have been shown to be effective in controlling blood sugar levels in people with type 2 diabetes, studies are still underway to find out what the long-term effects are of using these new drugs.

Another new type of drug are the sodium-glucose loop co-transporter 2 (SGLT-2) inhibitors. Some of the available drugs in this category are empagliflozin (Jardiance), dapagliflozin (Farxiga), canagliflozin (Invokana), and ertugliflozin (Steglatro). This class of medication lowers blood sugar by causing the kidneys to remove more glucose in the urine. These drugs are also used to reduce the risk of heart disease and kidney damage. SGLT-2 medications may increase urination. Serious, but rare side effects to watch for when taking these drugs include urinary or genital infections and ketoacidosis.

Will taking medicine for my diabetes make me gain weight?

Insulin and sulfonylureas, a type of diabetes pill (names include glimepiride and glipizide), can cause a person to gain some weight, usually 10 to 15 pounds over one to two years. This is because these medications help the body use all the sugar that comes from the food a person eats. Usually, the kidneys get rid of extra calories that our bodies don’t need for fuel by urinating away some of the sugar. When that person starts taking insulin or a sulfonylurea, the sugar enters the cells of the muscle, liver, and fat cells to be used for energy or stored for later. The kidneys don't get rid of the extra calories from the sugar, so the person probably will begin to gain some weight.

Insulin and sulfonylureas can also cause blood sugar to go too low. When that happens, a person must eat or drink something with sugar to get the blood sugar level back up to a normal range. If this happens often, then a person is eating or drinking a lot of extra calories to keep blood sugar levels normal. This can also cause the person to gain weight.

It is important when taking sulfonylureas to eat regularly scheduled meals and not skip meals.

If you find that you're gaining weight, talk to your doctor about how to adjust your medicine, food plan, and activity level so you can stay at a healthier weight.

Is it possible for a person to become immune to insulin after taking it for a long time?

This was a concern in the past when cows and pigs were a major source of commercial insulin. There were always very tiny amounts of impurities in the animal insulin. Most people's bodies reacted by making some antibodies to build immunity to the impurities.

Genetic engineering has allowed large-scale production of insulin that has the same molecular structure as human insulin, so we don't need to rely on pigs and cows anymore. We don't see much negative reaction to these newer insulin preparations, and little if any buildup of antibodies. So, it’s very unlikely that a person will become immune to the effects of insulin.

Don't confuse immunity to insulin with insulin resistance. These are two completely different things. When someone needs a lot more insulin than we might expect, it’s not because they are immune to insulin. It’s because their bodies aren’t able to use the insulin properly. Their bodies are resistant to the insulin, so they need more of it to get their blood sugars to a healthy range.

What's the difference between NovoLog and Humalog insulin?

Humalog is the brand name for Eli Lilly's rapid-acting analog insulin. Its generic name is insulin lispro. Novo Nordisk also makes a rapid-acting insulin analog sold under the brand name NovoLog. Its generic name is insulin aspart.

These two types of insulin analog are nearly the same in action. They start to work in 10 to 20 minutes, have their peak effect in about 45 to 90 minutes, and last about 3-4 hours.

Is it OK to switch brands of insulin?

Your doctor might prescribe different brands of insulin to use at different times of the day. Three companies make insulin: Eli Lilly, Novo Nordisk, and Sanofi. You can use insulin from these manufacturers as long as you don't mix them in the same syringe. Even with insulin from the same manufacturer, we don't recommend mixing them together. There may be some situations when mixing insulin may be safe and appropriate, but please discuss with your physician or diabetes provider if this right for your medications. It's important to know the kinds of insulin you're taking and what you and your doctor expect the insulin to do. If you are taking more than one type of insulin, be sure you know which one to take at which time of day and consider marking them to avoid mixing them up.


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