If you have diabetes, your doctor might suggest Basaglar (insulin glargine) as a treatment option for you. It’s a prescription drug used to treat:

Basaglar is a long-acting insulin. You should not take Basaglar to treat diabetic ketoacidosis (DKA).

Basaglar comes as a liquid solution that you inject under your skin. If this medication works for you, your doctor will likely recommend that you use it long term.

For more information about Basaglar, see this in-depth article.

Like other drugs, Basaglar can cause mild or serious side effects. Keep reading to learn more.

Some people may have mild to serious side effects during their Basaglar treatment. Examples of commonly reported side effects include:

  • itching
  • changes in your skin (such as thickening) where you inject your dose
  • injection site reaction*
  • weight gain*
  • hypoglycemia*

* To learn more about this side effect, see the “Side effects explained” section below.

These are just a few of the side effects Basaglar may cause. But not everyone who takes this medication will have adverse effects. Read on to learn about some of the mild to severe side effects of this drug.

Mild side effects are common in people using Basaglar. Examples of mild side effects that have been reported include:

  • itching
  • swelling, especially in your arms, hands, legs, or feet
  • changes in your skin where you inject your dose
  • injection site reaction*
  • weight gain*
  • rash*
  • hypoglycemia*

* To learn more about this side effect, see the “Side effects explained” section below.

In most cases, these side effects should be temporary. And some may be easily managed. But if you have symptoms that are ongoing or bother you, talk with your doctor or pharmacist. And don’t stop using Basaglar unless your doctor recommends it.

Basaglar may cause mild side effects other than the ones listed above. See Basaglar’s prescribing information for details.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Basaglar, visit MedWatch.

Though serious side effects are not common in people using Basaglar, they are possible. Serious side effects that have been reported with this drug include:

* To learn more about this side effect, see the “Side effects explained” section below.

If you develop serious side effects during your Basaglar treatment, call your doctor right away. If the side effects seem life threatening or if you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Most side effects experienced by children ages 6 years and older during Basaglar treatment were similar to those reported by adults. But in addition to the side effects listed above, Basaglar can also cause a runny nose in children. Basaglar is not approved to treat children younger than age 6 years.

Get answers to some frequently asked questions about Basaglar’s side effects.

Does the Basaglar KwikPen cause side effects that differ from those of the Tempo Pen?

Both Basaglar KwikPen and Basaglar Tempo Pen can cause the same side effects, such as:

This is because both pens contain the same active ingredient, insulin glargine. They also both contain the same strength of insulin glargine, at 100 units per milliliter (mL) of solution. And each pen contains 3 mL of medication.

The major difference between the two pens is that the Tempo pen can connect to your smartphone or device. This helps you keep track of your injections. For more information about the dosage and forms that Basaglar comes in, see this article.

Are Basaglar’s side effects the same as those of other types of insulin?

The side effects you may have with Basaglar are similar to those of other types of insulin. For example, all types of insulin are injectable drugs. This means they can all potentially cause an injection site reaction, such as:

  • redness or skin discoloration
  • pain
  • swelling at the injection site

Also, because all types of insulin work to lower your blood sugar in a similar way, they may all cause hypoglycemia (blood sugar that is too low).

There are many types of insulin available in the United States, including:

Differences among them include:

  • how long they work in your body
  • your dose
  • how often you need to take your dose

Talk with your doctor about the best type of insulin for you.

Am I at a higher risk of side effects if I’m using a higher dose of Basaglar?

You may be at an increased risk of side effects with a higher dose of Basaglar.

For example, low blood sugar may occur from using Basaglar. And with a higher dose of the drug, your risk of low blood sugar is increased.

If you have bothersome side effects, talk with your doctor. In some cases, they may recommend a decreased dose of Basaglar. Or they may suggest adding another medication so you can take a reduced dose of Basaglar.

Learn more about some of the side effects Basaglar may cause.

Weight gain

You may gain weight during your Basaglar treatment. This was a common side effect reported in people using this medication in studies. In fact, weight gain is a common side effect of any insulin medication.

What might help

If you gain weight, talk with your doctor. They’ll be able to help you determine what’s causing your weight gain. In some cases, it may be due to other causes, such as heart problems. Your doctor can suggest ways to manage weight gain, such as changing your diet or exercise routine.

Skin rash

While using this medication, you may notice a rash. Skin rash is a common side effect reported in people using Basaglar in studies.

What might help

Talk with your doctor about any rashes you have during your Basaglar treatment. They may want to see your rash to be sure it’s nothing more serious. In some cases, a rash can occur as a sign of an allergic reaction. Your doctor can help determine the cause of your rash and how best to treat it. In some cases, your rash may go away on its own.

Injection site reaction

You may notice an injection site reaction where you inject Basaglar. This was a common side effect in studies of the drug. Injection site reaction can include any or all of the following:

What might help

If you have a severe or bothersome injection site reaction, talk with your doctor. They may be able to recommend ways to help relieve them, such as a specific injection technique.

Hypoglycemia (low blood sugar)

It’s possible to develop low blood sugar while you’re using Basaglar. This is the most common side effect reported in studies of people using this medication.

Low blood sugar can be mild, severe, or even life threatening. During your Basaglar treatment, it’s important that you are aware of the symptoms of low blood sugar, which may include:

What might help

Before starting Basaglar, talk with your doctor about your risk of low blood sugar and the best way to treat it. Some people may be at higher risk of this side effect. This includes those who:

If any of the factors above apply to you, or you have any other medical conditions, tell your doctor right away. In some cases, your dose of Basaglar may need to be adjusted to help prevent low blood sugar.

If you do notice symptoms of low blood sugar, it’s important to treat it immediately. The American Diabetes Association recommends having 15 grams (g) of carbohydrates to increase your blood sugar level. Then, 15 minutes later, check your blood sugar again to see if the level has returned to normal. If your blood sugar is still low, you can repeat this process. Examples of food that can help to quickly increase your blood sugar include:

  • glucose tablets
  • 4 ounces of juice or (non-diet) soda
  • 1 tablespoon of sugar or honey
  • hard candies

Before you start treatment with Basaglar, your doctor will discuss the risk of low blood sugar with you. They can help you create an action plan to treat low blood sugar episodes if they do occur.

Allergic reaction

Like most drugs, Basaglar can cause an allergic reaction in some people. Symptoms can be mild or serious and include:

  • skin rash
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)
  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest an over-the-counter oral antihistamine, such as Benadryl (diphenhydramine), or a topical product, such as hydrocortisone cream, to manage your symptoms.

If your doctor confirms you’ve had a mild allergic reaction to Basaglar, they’ll decide if you should continue taking it.

If you have symptoms of a severe allergic reaction, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you’ve had a serious allergic reaction to Basaglar, they may have you switch to a different treatment.

Keeping track of side effects

During your Basaglar treatment, consider keeping notes on any side effects you’re having. You can then share this information with your doctor. This is especially helpful when you first start taking new drugs or using a combination of treatments.

Your side effect notes can include things such as:

  • what dose of drug you were using when you had the side effect
  • how soon you had the side effect after starting that dose
  • what your symptoms were
  • how it affected your daily activities
  • what other medications you were taking
  • any other information you feel is important

Taking notes and sharing them with your doctor will help them learn more about how Basaglar affects you. They can use this information to adjust your treatment plan if needed.

Basaglar may not be right for you if you have certain medical conditions or other factors that affect your health. Talk with your doctor about your health history before starting Basaglar. Below are some factors to consider.

Heart problems, such as heart failure. If you have heart problems and are also taking a type of drug called a thiazolidinedione (TZD), you may be at an increased risk of heart failure. If you already have heart problems, including heart failure, using these drugs together may increase your risk and make your disease worse. In this case, your doctor may recommend monitoring your symptoms and heart condition more often. In some cases, they may recommend a different treatment option for you.

Allergic reaction. If you’ve had an allergic reaction to Basaglar or any of its ingredients, your doctor will likely not prescribe it for you. Ask them what other medications are better options for you.

Hypoglycemia (low blood sugar). You should not take Basaglar if you currently have low blood sugar. This medication will cause your blood sugar to become even lower. Low blood sugar can be serious or even life threatening. If you have low blood sugar, your doctor will recommend that you treat it before starting Basaglar.

Low potassium levels. If you have hypokalemia (low potassium levels), tell your doctor before starting Basaglar. They’ll likely recommend that you take medication to increase your potassium levels before starting Basaglar. This is because Basaglar can lower your potassium levels. If you already have low potassium, using this drug may make your potassium levels even lower.

Alcohol and Basaglar

Drinking alcohol during your Basaglar treatment may cause an increase or decrease in your blood sugar level. Due to this risk, your doctor may recommend limiting your alcohol consumption while you’re using Basaglar. Talk with them about how much alcohol, if any, is safe for you to drink while using this drug.

Pregnancy and breastfeeding while using Basaglar

It isn’t known if Basaglar is safe to use during pregnancy or while breastfeeding. At this time, studies of pregnant women using Basaglar haven’t shown an increased risk of problems with fetal development (commonly known as birth defects). Also, untreated diabetes during pregnancy can increase the risk of harm to both the mother and the developing fetus.

It isn’t known if Basaglar is present in breastmilk or what effects it might have on a breastfeeding baby.

Before starting Basaglar, tell your doctor if you’re pregnant, breastfeeding, or planning on either. They’ll recommend the best treatment plan for you.

Basaglar is a prescription drug used to treat diabetes in adults and some children. While side effects are common with this medication, most of them are mild. Before starting Basaglar, you may wish to talk with your doctor about it. Here are a few questions you may want to ask to help get you started:

  • How often should I rotate my injection site to prevent thickening of the skin where I inject Basaglar?
  • How can I manage side effects that I have from this medication?
  • I also have other medical conditions. Am I at an increased risk of side effects?

If you have type 2 diabetes, consider signing up for Healthline’s online newsletter to get news on treatments and tips for managing your condition. You can also find support and advice from our Bezzy type 2 diabetes community.


Do the other diabetes medications that I take increase my risk of side effects from Basaglar?



It’s possible. Depending on the diabetes medications, taking them with Basaglar may increase your risk of hypoglycemia (low blood sugar). For example, metformin is a very commonly prescribed diabetes medication. You could possibly take metformin with Basaglar, but taking them together increases your risk of hypoglycemia. You’ll need to work with your doctor to monitor your blood sugar more closely if you begin taking certain diabetes medications together.

If you have questions about any medications you’re currently taking and how they may interact with Basaglar, talk with your doctor.

Dena Westphalen, PharmDAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.
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Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.