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

David Snyder, PharmD, BCPP, is a board-certified clinical pharmacist and psychopharmacology expert at McLean Hospital in Belmont, Massachusetts.

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.

Generic Name: Insulin glargine, recombinant

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

Therapeutic Classification: Antidiabetic, long-acting insulin

Controlled Substance: N/A

Active Ingredient: Insulin glargine

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

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.

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:

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.

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

Healthcare providers may prescribe insulin glargine for:

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.

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 fda.gov/medwatch or 1-800-FDA-1088.

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:

Other common side effects of Basaglar include:

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:

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:

Moderate delayed or long-term side effects can include:  

Severe long-term side effects may include:  

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).

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.

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

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.

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.

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.

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:

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:

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.

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:

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:

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.

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

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.

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.

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.

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.

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.

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.

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.

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:

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

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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MedlinePlus. Insulin glargine (rDNA origin) injection.

Prescribers’ Digital Reference. Insulin glargine - drug summary.

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

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

American Diabetes Association. Hypoglycemia (low blood sugar).

Food and Drug Administration. Lantus label.

DailyMed. Semglee- insulin glargine-yfgn injection, solution.

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

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