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Overview: Insulin glargine is a long-acting insulin used to lower blood sugar levels in people with diabetes. It helps get sugar into your cells, so your body can use it for energy. The most common side effects are low blood sugar, weight gain, and pain, redness, itching or swelling at the injection site. Contact your healthcare provider right away if you have severe or frequent low blood sugar or if you feel weak or unusually tired.

Uses

What is insulin glargine used for?

Insulin glargine is commonly used to help lower blood sugar levels in people with either type 1 diabetes or type 2 diabetes.

Insulin glargine may also be used for other conditions as determined by your healthcare provider.

How does insulin glargine work (mechanism of action)?

Insulin glargine works to help keep your blood sugar levels from getting too high. Insulin glargine provides a substance called insulin that works throughout the day. Insulin glargine helps get sugar into your cells so your body can use it for energy. It also stops your liver from making sugar and helps make protein in your tissues.

How is insulin glargine supplied (dosage forms)?

Brands and other names

  • Basaglar
  • Lantus
  • Lantus Solostar
  • Rezvoglar
  • Semglee
  • Toujeo SoloStar
  • Toujeo Max SoloStar

Dosage forms and strengths

  • 100 units/mL vial
  • 100 units/mL pen-injector
  • 300 units/mL pen-injector

How should I store insulin glargine?

Store in a place that is not exposed to direct sunlight and heat. Do not freeze. Before opening the vials or pens, insulin glargine can be stored at room temperature or in the refrigerator between 36 F to 46 F (2 C to 8 C). If unopened and stored in the refrigerator, insulin glargine can be used up to the expiration date. Talk to your pharmacist about how long unopened vials or pens are good if stored at room temperature, how to store opened vials or pens, and how long you can use specific insulin glargine vials or pens once they have been opened.

Store KwikPens, SoloStars, Tempos, and other pens without the needle attached.

Side Effects

What are the most common side effects of insulin glargine?

The most common side effects of insulin glargine are listed below. Tell your healthcare provider if you have any of these side effects that bother you.

  • Low blood sugar (hypoglycemia) (see below)
  • Allergic reactions, such as rash and itching (see below)
  • Pain, itching, swelling, or redness near the the injection site
  • Skin thickening or pits at the injection site (also called lipodystrophy)
  • Fluid retention, especially in the hands or feet (peripheral edema)
  • Weight gain

There may be other side effects of insulin glargine that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of insulin glargine?

While less common, the most serious side effects of insulin glargine are described below, along with what to do if they happen.

Severe Allergic Reactions. Insulin glargine may cause allergic reactions, which can be serious. Stop using insulin glargine and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Low Blood Sugar (Hypoglycemia). Insulin glargine can cause low blood sugar, which can be serious and may lead to death. You may need to check your blood sugar more often if you have changes to your diet, exercise regimen, or medicines for diabetes. Do not use insulin glargine and call your healthcare provider right away if you have any of the following symptoms of hypoglycemia.

  • Headache
  • Crankiness or anxiety
  • Hunger
  • Dizziness or confusion
  • Blurry vision
  • Slurred speech
  • Sweating
  • Feeling jittery or shakiness
  • Fast heartbeat
  • Seizures

Medication Error. If you are using multiple insulin products, accidentally mixing them up and using the wrong insulin or the wrong dose can cause low blood sugar (hypoglycemia). Always check the label on your insulin products before using them to make sure you are using the correct insulin. Call your healthcare provider right away if you have any of the following symptoms of hypoglycemia [see Low Blood Sugar (Hypoglycemia) above] from either insulin glargine or any other insulin product that you are using.

Low Potassium Level (Hypokalemia). Insulin glargine can cause a low potassium level, which can be serious and may lead to death. Your healthcare provider will check your potassium levels, especially if you take certain other medicines. Call your healthcare provider if you have any of the following symptoms of a low potassium level.

  • Weakness
  • Unusual tiredness
  • Muscle cramps or twitching
  • Constipation

Warnings & Precautions

Who should not use insulin glargine?

Allergies to Ingredients. People who are allergic to any of the following should not use insulin glargine.

  • Insulin glargine
  • Basaglar
  • Lantus
  • Toujeo
  • Rezvoglar
  • Semglee
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific insulin glargine products they stock.

Low Blood Sugar (Hypoglycemia). Insulin glargine should not be used if you are having an episode of low blood sugar (hypoglycemia). Using insulin glargine while your blood sugar is low can worsen your symptoms of low blood sugar (hypoglycemia). See the Side Effects section for more details.

What should I know about insulin glargine before using it?

Do not use insulin glargine unless it has been prescribed to you by a healthcare provider. Use it as prescribed. This medicine is to be injected under the skin. Make sure that you or a caregiver understands how to properly prepare and use insulin glargine. If you have any questions, talk to your pharmacist or other healthcare provider.

Do not share insulin glargine with other people, even if they have the same condition as you. It may harm them. Do not share needles or syringes with another person. Always use a new needle or syringe for each injection.

Keep insulin glargine out of the reach of children. Since this medicine may be kept in a refrigerator, take special precautions to keep it away from children who also use the refrigerator.

Follow the “Instructions for Use” when using insulin glargine for the first time or when you have not used it in a while. Check the label on your insulin glargine each time you use it to make sure you are using the correct insulin.

Do not use the same exact spot for each insulin glargine injection. Do not inject where your skin is thickened, hard, or has pits or lumps. Do not inject into tender, bruised, or scarred skin.

Insulin glargine can affect your alertness or coordination. Do not drive or do other activities that require alertness or coordination until you know how insulin glargine affects you.

Certain conditions that cause increased stress on your body, like fever, trauma (such as a car accident), infection, or surgery, can change the amount of diabetes medicines you need to take to control your diabetes. Talk to your healthcare provider if you have any of these conditions to decide if your medicine needs to be changed.

Some medicines may make it difficult to notice signs of low blood sugar. Talk to your healthcare provider about how to prevent, recognize, and manage low blood sugar (hypoglycemia), high blood sugar (hyperglycemia), and diabetes-related problems.

People who are 65 years or older can be at greater risk for some side effects from insulin glargine. Talk to your healthcare provider about your risks if you are in this age group.

What should I tell my healthcare provider before using insulin glargine?

Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if insulin glargine is right for you.

In particular, make sure that you discuss any of the following.

Other Current and Past Health Conditions. Tell your healthcare provider if you have any of the following.

  • No awareness of low blood sugar level
  • Kidney or liver problems

Diet and Lifestyle Changes. Tell your healthcare provider if you have any changes in your diet, level of physical activity, or illnesses. These may affect the amount of insulin glargine you need.

Other Medicines and Supplements. Insulin glargine may interact with other medicines and supplements. Before using insulin glargine, tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how insulin glargine could affect pregnancy or harm an unborn baby. Tell your healthcare provider if you are or plan to become pregnant. Your healthcare provider will advise you if you should use insulin glargine while you are pregnant or trying to get pregnant. Uncontrolled diabetes can increase the risk of harm to a mother and an unborn baby. Your healthcare provider will discuss the best way to control your blood sugar.

Breastfeeding. It is not known if insulin glargine passes into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed. Your healthcare provider will advise you if you should use insulin glargine while breastfeeding.

Interactions

Does insulin glargine interact with foods or drinks?

There are no known interactions between insulin glargine and foods or drinks.

Do not drink alcohol or use any medicines that have alcohol in them while using Afrezza. Alcohol may affect blood sugar levels in people with diabetes. 

Do not drink alcohol or use any medicines that have alcohol in them while using insulin glargine. Alcohol may affect blood sugar levels in people with diabetes. 

Does insulin glargine interact with other medicines (drug interactions)?

Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before using insulin glargine.

  • A beta-blocker, such as metoprolol (Lopressor, Toprol XL, and others), atenolol (Tenormin), or propranolol (Inderal LA, Innopran XL), which is a medicine that may be used for certain heart conditions or to reduce blood pressure
  • Clonidine (Catapres-TTS and others), which is a medicine used for high blood pressure or attention deficit hyperactivity disorder (ADHD)
  • Pioglitazone (Actos), or any other medicine for diabetes

Many other medicines can increase your blood sugar, or can increase or decrease the impact insulin glargine has on your blood sugar. Talk to your pharmacist or healthcare provider before starting or stopping other medicines while using glargine. You may need to monitor your blood sugar levels more closely during these times.

This may not be a complete list of medicines that can interact with insulin glargine. Always check with your healthcare provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much insulin glargine?

If you or someone else has used too much insulin glargine, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of insulin glargine?

It is important to use your insulin glargine exactly as it is prescribed. Talk to your healthcare provider, ahead of time, about what you should do if you miss a dose of insulin. Do not use double or extra doses.