Basaglar (Insulin Glargine) - Subcutaneous

What Is Basaglar?

Basaglar (insulin glargine) is a prescription long-acting basal insulin. It is used by adults and children with type 1 diabetes or adults with type 2 diabetes to improve blood sugar control.

Basal insulin holds blood sugar steady throughout the day and night (in the absence of food). People with type 1 diabetes (and some with type 2 diabetes) also use short-acting (bolus) insulin at mealtimes and when needed to correct high blood sugar.

Insulin glargine is a man-made form of insulin, a hormone that regulates blood sugar levels. Insulin glargine works by replacing insulin normally made by the body. Basaglar inhibits sugar production in the liver and moves sugar from the blood to other body tissues to be used for energy.

Insulin glargine is available under several brand names, including Basaglar, Lantus, Semglee, and Toujeo. Basaglar is given by subcutaneous (under the skin) injection, into the thigh, buttocks, upper arm, or stomach. It is available in two prefilled pen injections: The Basaglar KwikPen and Basaglar Tempo Pen.

Drug Facts

Generic Name: Insulin glargine, recombinant

Brand Name(s): Basaglar, Lantus, Lantus SoloStar, Rezvoglar KwikPen, Semglee, Semglee Pen, Toujeo

Drug Availability: Prescription

Administration Route: Subcutaneous

Therapeutic Classification: Antidiabetic, long-acting insulin

Available Generically: No

Controlled Substance: N/A

Active Ingredient: Insulin glargine

Dosage Form(s): Subcutaneous

What Is Basaglar Used For?

The Food and Drug Administration (FDA) approved Basaglar to improve glycemic, or blood sugar, control in:

  • Adults and children (6 years and older) with type 1 diabetes
  • Adults with type 2 diabetes

Basaglar is not indicated to treat diabetic ketoacidosis (DKA). DKA is a life-threatening complication of diabetes. In DKA, the body makes high levels of blood acids, or ketones. DKA is more common in people with type 1 diabetes but may also occur in people with type 2 diabetes.

How to Take Basaglar

Before starting Basaglar, read the patient information leaflet with your prescription. Discuss any questions or concerns with your healthcare provider. It is important to use this medication exactly as instructed. Do not skip doses or use more or less than prescribed.

Before injecting Basaglar, check the label to ensure you have the correct insulin. Here are a few tips for using insulin glargine:

  • Take it at the same time every day. You can choose the most convenient time for you as long as you take your dose at the same time each day.
  • Check the solution before injecting it. It should be clear and colorless. Call your pharmacy if the solution appears cloudy or colored.
  • Inject insulin glargine under the skin of the stomach, upper arms, buttocks, or thigh. Do not inject it into a muscle or vein or use it in an insulin pump.
  • Always rotate injection sites, meaning do not use the same injection location over and over. Changing injection sites lowers your chance of skin reactions at the injection sites. Never inject into lumpy, thick, tender, bruised, hard, scarred, or damaged skin.
  • Do not mix Basaglar with any other insulin or injection.
  • Use a new needle for every injection. Never reuse or share a syringe or pen.

Check blood sugar levels as instructed by your healthcare provider. Your healthcare provider will tell you what range your blood sugar should be in and how often you should check it.

Talk to your healthcare provider about low blood sugar or hypoglycemia and how to treat it (for example, drinking or eating a certain amount of fast-acting sugar such as juice or glucose tablets). Symptoms of low blood sugar can include hunger, dizziness, shakiness, blurred vision, and confusion. Also, ask your healthcare provider about a glucagon prescription, such as Baqsimi, which can be used in an emergency to treat low blood sugar. 


Store unopened insulin glargine in the refrigerator (up until the expiration date), or store at room temperature (68 F to 77 F) and use it within 28 days. Never freeze the solution; insulin is a temperature-sensitive medication that needs to be kept at proper temperatures.

After opening your medication, keep it at room temperature and away from heat, direct light, and moisture. Make sure to remove the needle before putting the pen away. Place the needle in a sharps container. Do not reuse or share needles. Keep Basaglar out of the reach of children and pets.

Off-Label Uses

Insulin glargine is sometimes used off-label for indications that are not FDA approved.

Healthcare providers may prescribe insulin glargine for:

  • Children and adolescents with type 2 diabetes not controlled with diet, exercise, and oral medicines
  • Children and adolescents who are overweight and newly diagnosed with type 2 diabetes
  • Children aged 2 to 5 years with type 1 diabetes

How Long Does Basaglar Take to Work?

One dose of Basaglar reaches its highest levels by 12 hours after an injection, but Basaglar is designed to keep blood sugar levels stable (in the absence of food) over 24 hours. Therefore, Basaglar holds blood sugar steady throughout the day and night when taken once daily.

What Are the Side Effects of Basaglar?

This is not a complete list of side effects, and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your healthcare provider. You may report side effects to the FDA at or 1-800-FDA-1088.

Common Side Effects

One of the most common side effects of insulin glargine is hypoglycemia (low blood sugar). Hypoglycemia can come on suddenly, and symptoms may vary from person to person. Therefore, it is important to monitor your blood sugar carefully. Changes in meal patterns, physical activity levels, and co-administered medications can all increase your risk of hypoglycemia.

Symptoms of hypoglycemia may include, but are not limited to:

  • Shakiness
  • Nervousness or anxiety
  • Sweating or chills
  • Heart palpitations
  • Lightheadedness or dizziness
  • Nausea
  • Confusion or irritability
  • Hunger

Other common side effects of Basaglar include:

  • Injection site reaction or lipodystrophy (pits in the skin or thickened skin)
  • Muscle pain
  • Itching or rash
  • Upper respiratory infection or flu
  • Weight gain
  • Headache 
  • Peripheral edema (swelling of the extremities)
  • Hypersensitivity reaction

Severe Side Effects

Call your healthcare provider immediately if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and symptoms can include the following:

  • Hypersensitivity reaction or anaphylaxis: Symptoms can include rash, hives, swelling around the lips, tongue, and face, or difficulty breathing. These symptoms require emergency medical attention. 
  • Hypoglycemia (low blood sugar): Talk to your healthcare provider about how often you should monitor your blood sugar and how to treat episodes of low blood sugar. In addition, be aware of low blood sugar symptoms, such as hunger, dizziness, shaking, sweating, confusion, blurred vision, and irritability. 
  • Hypokalemia (low potassium levels): Symptoms of low potassium can include leg cramps, constipation, irregular heartbeat, fluttering in the chest, increased thirst or urination, numbness and tingling, muscle weakness, and a limp feeling. Call your healthcare provider immediately if any of these symptoms occur.

Long-Term Side Effects

While many people tolerate Basaglar well, long-term or delayed side effects are possible.

Some delayed or long-term side effects can be mild, such as:

  • Infection or flu
  • Muscle and joint pain
  • Weight gain 
  • Insulin resistance (the body does not respond as well to insulin, resulting in increased blood sugar levels)

Moderate delayed or long-term side effects can include: 

Severe long-term side effects may include: 

  • Insulin shock, which can cause severely low blood sugar
  • Retinopathy (eye complications related to diabetes that can cause vision loss and blindness)

Report Side Effects

Basaglar may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Basaglar Should I Take?

Drug Content Provided and Reviewed by IBM Micromedex®

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For injection dosage form (solution):
    • Basaglar® or Lantus®:
      • For type 1 diabetes mellitus:
        • Adults and children 6 years of age and older—Dose is based on your blood sugar and must be determined by your doctor.
        • Children younger than 6 years of age—Use and dose must be determined by your doctor.
      • For type 2 diabetes mellitus:
        • Adults—Dose is based on your blood sugar and must be determined by your doctor.
        • Children—Use and dose must be determined by your doctor.
    • Toujeo®:
      • For type 1 diabetes mellitus:
        • Adults and children 6 years of age and older—Dose is based on your blood sugar and must be determined by your doctor.
        • Children younger than 6 years of age and older—Use and dose must be determined by your doctor.
      • For type 2 diabetes mellitus:
        • Adults and children 6 years of age and older—Dose is based on your blood sugar and must be determined by your doctor.
        • Children younger than 6 years of age and older—Use and dose must be determined by your doctor.


Due to the possible effects of this medication, there may be changes to how it is used based on certain factors:

  • Children: Basaglar is approved for use in children with type 1 diabetes who are 6 years and older, but it is not FDA-approved for children with type 2 diabetes.
  • Women who are pregnant or breastfeeding: Consult your healthcare provider if you are pregnant, planning to become pregnant, or are breastfeeding. If you already use Basaglar and find out that you are pregnant, notify your healthcare provider.
  • Adults over 65: Basaglar may be prescribed in older adults if the healthcare provider determines that the benefits outweigh the risks. Basaglar’s prescribing information recommends conservative dosing to avoid episodes of low blood sugar.
  • People with kidney or liver problems: Basaglar may be prescribed with caution in people who have kidney or liver problems if the healthcare provider determines it is safe. In these cases, you may need frequent monitoring and/or a dose adjustment.

Missed Dose

Ask your healthcare provider for guidance if you miss a dose. Do not take more than one dose in 24 hours, unless your healthcare provider instructs you to do so. Refilling your prescription several days early will help ensure that you do not miss a dose of Basaglar.

Overdose: What Happens If I Take Too Much Basaglar?

Taking too much Basaglar can cause low blood sugar and low potassium levels. More severe overdoses of Basaglar may cause severe low blood sugar with coma, seizure, or neurologic impairment.

What Happens If I Overdose on Basaglar?

If you think you or someone else may have overdosed on Basaglar, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Basaglar, call 911 immediately.


Drug Content Provided and Reviewed by IBM Micromedex®

Never share insulin pens or cartridges with others under any circumstances. It is not safe for one pen to be used for more than one person. Sharing needles or pens can result in transmission of hepatitis viruses, HIV, or other bloodborne illnesses.

Your doctor will want to check your progress at regular visits, especially during the first few weeks you use this medicine. Blood tests may be needed to check for unwanted effects.

It is very important to follow carefully any instructions from your health care team about:

  • Alcohol—Drinking alcohol may cause severe low blood sugar. Discuss this with your health care team.
  • Other medicines—Do not take other medicines during the time you are using insulin glargine unless they have been discussed with your doctor. This especially includes nonprescription medicines such as aspirin, and medicines for appetite control, asthma, colds, cough, hay fever, or sinus problems.
  • Counseling—Other family members need to learn how to prevent side effects or help with side effects if they occur. Also, patients with diabetes may need special counseling about diabetes medicine dosing changes that might occur because of lifestyle changes, such as changes in exercise and diet. Furthermore, counseling on contraception and pregnancy is needed because of the problems that can occur in patients with diabetes during pregnancy.
  • Travel—Keep a recent prescription and your medical history with you. Be prepared for an emergency as you would normally. Make allowances for changing time zones and keep your meal times as close as possible to your usual meal times.

In case of emergency—There may be a time when you need emergency help for a problem caused by your diabetes. You need to be prepared for these emergencies. It is a good idea to:

  • Wear a medical identification (ID) bracelet or neck chain at all times. Also, carry an ID card in your wallet or purse that says that you have diabetes and a list of all of your medicines.
  • Keep an extra supply of insulin glargine and syringes with needles or injection devices on hand in case high blood sugar occurs.
  • Keep some kind of quick-acting sugar handy to treat low blood sugar.
  • Have a glucagon kit and a syringe and needle available in case severe low blood sugar occurs. Check and replace any expired kits regularly.

Too much insulin glargine can cause hypoglycemia (low blood sugar). Low blood sugar also can occur if you use insulin glargine with another antidiabetic medicine, changes in insulin regimen (eg, insulin strength, type of insulin, injection site), delay or miss a meal or snack, exercise more than usual, or drink alcohol. Symptoms of low blood sugar must be treated before they lead to unconsciousness (passing out). Different people may feel different symptoms of low blood sugar. It is important that you learn which symptoms of low blood sugar you usually have so that you can treat it quickly.

Symptoms of low blood sugar include anxiety, behavior change similar to being drunk, blurred vision, cold sweats, confusion, difficulty in thinking, dizziness or lightheadedness, drowsiness, excessive hunger, fast heartbeat, headache, irritability or abnormal behavior, nervousness, nightmares, restless sleep, shakiness, slurred speech, and tingling in the hands, feet, lips, or tongue.

If symptoms of low blood sugar occur, eat glucose tablets or gel, corn syrup, honey, or sugar cubes, or drink fruit juice, non diet soft drink, or sugar dissolved in water to relieve the symptoms. Also, check your blood for low blood sugar. Get to a doctor or a hospital right away if the symptoms do not improve. Someone should call for emergency help immediately if severe symptoms such as convulsions (seizures) or unconsciousness occur. Have a glucagon kit available, along with a syringe and needle, and know how to use it. Members of your household also should know how to use it.

Hyperglycemia (high blood sugar) may occur if you do not take enough or skip a dose of your antidiabetic medicine, changes in insulin regimen, overeat or do not follow your meal plan, have a fever or infection, or do not exercise as much as usual.

Symptoms of high blood sugar include blurred vision, drowsiness, dry mouth, flushed, dry skin, fruit-like breath odor, increased urination, ketones in the urine, loss of appetite, stomachache, nausea, or vomiting, tiredness, trouble breathing (rapid and deep), unconsciousness, and unusual thirst.

If symptoms of high blood sugar occur, check your blood sugar level and then call your doctor for instructions.

This medicine may make you dizzy or drowsy. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.

This medicine may cause serious allergic reactions, including anaphylaxis, which can be life-threatening and requires immediate medical attention. Call your doctor right away if you have a rash, itching, trouble breathing, trouble swallowing, or any swelling of your hands, face, or mouth while you are using this medicine.

This medicine may cause low levels of potassium in your blood. Do not use medicines, supplements, or salt substitutes that contain potassium unless you have discussed this with your doctor.

Using this medicine together with other diabetes medicine (eg, pioglitazone, rosiglitazone, Actos®, Actoplus Met®, Avandia®) may cause serious heart problems or edema (fluid retention). Check with your doctor immediately if you are rapidly gaining weight, having chest pain or discomfort, extreme tiredness or weakness, trouble breathing, uneven heartbeat, or excessive swelling of the hands, wrist, ankles, or feet.

What Are Reasons I Shouldn’t Take Basaglar?

Basaglar is not appropriate for everyone. You should not take this medication if you are allergic to insulin glargine or any of the inactive ingredients in Basaglar.

Basaglar should not be used during a low blood sugar episode. Never inject it into a vein or muscle or use it in an insulin pump.

Basaglar may be prescribed with caution in some people only if the healthcare provider determines it is safe, including those:

  • Experiencing illness, stress, or infection
  • With low potassium levels
  • With localized cutaneous amyloidosis (skin with lumps)
  • With visual impairment
  • With kidney or liver problems

What Other Medications May Interact With Basaglar?

Tell your healthcare provider about all of the medicines you take, including prescription and over-the-counter (OTC) drugs, and vitamins or supplements.

Certain drugs can increase the risk of low blood sugar episodes when combined with Basaglar. In these cases, a lower dose of Basaglar and more frequent monitoring may be required. Examples of these drugs include:

Certain drugs can decrease Basaglar’s effect, possibly requiring a higher dose of Basaglar as well as more frequent monitoring. Examples of these drugs include:

Certain drugs or substances may increase or decrease the effect of Basaglar. Some examples include:

Some drugs can mask symptoms of low blood sugar. This would require more frequent blood sugar monitoring. Examples of these drugs include:

  • Beta-blockers
  • Clonidine 
  • Reserpine

This is not a full list of drug interactions. Other drug interactions may occur with Basaglar. Consult your healthcare provider for a complete list of drug interactions.

What Medications Are Similar?

Basaglar contains the ingredient insulin glargine. Insulin glargine is also available as other brand-name insulins, such as:

  • Lantus contains the same ingredient, insulin glargine, and is available in the same dosage of Basaglar (100 units per milliliter [mL]). Lantus is indicated for use in adults with type 1 or type 2 diabetes and in children with type 1 diabetes who are at least 6 years old. 
  • Semglee is a biosimilar product to Lantus. Semglee contains insulin glargine (100 units per milliliter). Semglee was approved in July 2021 as the first interchangeable biosimilar insulin product approved by the FDA. This means that Semglee can be substituted for its reference product drug, Lantus. Semglee can be used in adults with type 1 or type 2 diabetes and children with type 1 diabetes who are at least 6 years old.
  • Toujeo also contains insulin glargine. Toujeo is available in a higher dose than Lantus (300 units per milliliter). It can be used in adults with type 1 or type 2 diabetes.

Soliqua is an injectable medication containing two drugs: insulin glargine and lixisenatide (a GLP-1 agonist). Soliqua can be used, along with diet and exercise, to improve blood sugar control in adults with type 2 diabetes.

Other long-acting insulins include Levemir (insulin detemir) and Tresiba (insulin degludec).

People with type 1 diabetes and sometimes with type 2 diabetes also use short-acting insulin. Short-acting insulin is used before meals or if blood sugar is too high to lower blood sugar levels. Examples of short-acting insulins are Humalog (insulin lispro) and Novolog (insulin aspart).

This list is a list of insulins also prescribed for diabetes. It is NOT a list of drugs recommended to take with Basaglar. Ask your pharmacist or a healthcare provider if you have questions.

Frequently Asked Questions

  • What is Basaglar used for?

    Basaglar (insulin glargine) is used to improve blood sugar control in adults with type 1 or type 2 diabetes, and children 6 years and older with type 1 diabetes.

  • How does Basaglar work?

    Basaglar replaces the insulin normally made by the body. It inhibits sugar production in the liver and helps move sugar out of the blood to other body tissues, where it is used for energy.

  • What drugs should not be taken with Basaglar?

    Several drugs can interact with Basaglar in different ways. See the above Interactions section for more details and examples. Before taking Basaglar, review your medication list with your healthcare provider.

  • How long does it take for Basaglar to work?

    A single dose of Basaglar reaches its highest amount in the body by 12 hours after injection. Basaglar holds blood sugar levels constant over a 24-hour period (in the absence of food). When taken once a day, Basaglar is used to keep blood sugar levels steady throughout the day and night.

  • What are the side effects of Basaglar?

    The most common side effects of Basaglar are hypoglycemia (low blood sugar), reactions at the injection site, muscle pain, itching, rash, upper respiratory infection, flu, headache, and peripheral edema (swelling of the extremities).

    Get emergency medical help immediately if you experience symptoms of a rare but severe allergic reaction, including hives, difficulty breathing, or swelling around the face, lips, tongue, or throat.

  • How do I stop taking Basaglar?

    Your healthcare provider will advise you on how long to take Basaglar. Do not stop taking the medication unless your healthcare provider tells you to do so.

How Can I Stay Healthy While Taking Basaglar?

Before taking Basaglar, discuss your medical history and medications with your healthcare provider.

When taking Basaglar, follow your healthcare provider’s instructions for use. Read the patient information that accompanies your prescription. Consult your healthcare provider with any questions or concerns. Ask them about blood sugar monitoring. Make sure you understand how and when to test your blood sugar and how to treat low blood sugar.

Avoid drinking alcohol while taking Basaglar. Be aware that certain medications, such as cough syrups contain alcohol. Check labels and ask your pharmacist if you have any questions about alcohol content in drugs.

Put together a diabetes kit to keep with you at all times. This may include:

  • Your blood glucose testing meter and supplies (e.g., strips, lancing device, lancets, alcohol wipes, and extra batteries)
  • Emergency contact information
  • Glucagon 
  • Treatment for low blood sugar (e.g., juice boxes and glucose tablets);

It is also a good idea to wear a medical alert at all times to alert emergency responders that you have diabetes.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  3. Prescribers’ Digital Reference. Insulin glargine - drug summary.

  4. Hurren KM, O'Neill JL. Pharmacodynamic and pharmacokinetic evaluation of insulin glargine U300 for the treatment of type 1 diabetes. Expert Opin Drug Metab Toxicol. 2016;12(12):1521-1526. doi:10.1080/17425255.2016.1245722

  5. Hoy SM. MYL1501D Insulin glargine: a review in diabetes mellitusBioDrugs. 2020;34:245–251. doi:10.1007/s40259-020-00418-x

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By Karen Berger, PharmD
Karen Berger, PharmD, is a community pharmacist and medical writer/reviewer.