Insulin Glargine

Insulin glargine lowers blood sugar. Do not dilute it and do not mix with any other type of insulin.

Insulin Glargine Overview


Insulin glargine is a prescription medication used to treat type 1 and type 2 diabetes. Insulin glargine, a long-acting form of insulin, works by replacing the insulin that is normally produced by the body and by helping the body to use sugar for energy. It also stops the liver from producing more sugar.

This medication comes in an injectable form to be injected under the skin (subcutaneously). Insulin glargine is usually injected once daily.

Common side effects include low blood sugar, redness and skin thickening at the injection site, and weight gain.

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  • Other
  • Diabetes Mellitus, Type 1
  • Diabetes Mellitus, Type 2
  • Hyperglycemia

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Insulin Glargine Cautionary Labels


Uses of Insulin Glargine

Insulin glargine is a prescription medication used to treat people with type 1 and type 2 diabetes for the control of high blood sugar. Insulin glargine may be used along with fast-acting insulin or oral medications to control blood sugar.

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

Insulin Glargine Brand Names

Insulin Glargine may be found in some form under the following brand names:

Insulin Glargine Drug Class

Insulin Glargine is part of the drug class:

Side Effects of Insulin Glargine

Insulins, including insulin glargine, can cause hypoglycemia (low blood sugar), hyperglycemia (high blood sugar), allergy, fluid retention, weight gain, and skin reactions.

Hypoglycemia (low blood sugar): Early warning signs of low blood sugar may be different, less noticeable or not noticeable at all in some people. That is why it is important to check your blood sugar as you have been advised by your doctor.

Symptoms of low blood sugar may include:

  • anxiety, irritability, restlessness, trouble concentrating, personality changes, mood changes, or other abnormal behavior
  • tingling in your hands, feet, lips, or tongue
  • dizziness, light-headedness, or drowsiness
  • nightmares or trouble sleeping
  • headache
  • blurred vision
  • slurred speech
  • palpitations (fast heartbeat)
  • sweating
  • tremor (shaking)
  • unsteady gait (walking).

If you have low blood sugar often or it is hard for you to know if you have the symptoms of low blood sugar, talk to your doctor.

Mild to moderate low blood sugar is treated by eating or drinking carbohydrates, such as fruit juice, raisins, sugar candies, milk or glucose tablets. Talk to your doctor about the amount of carbohydrates you should eat to treat mild to moderate low blood sugar.

Severe low blood sugar may require the help of another person or emergency medical people. A person with low blood sugar who is unable to take foods or liquids with sugar by mouth, or is unconscious needs medical help fast and will need treatment with a glucagon injection or glucose given intravenously (IV). Without medical help right away, serious reactions or even death could happen.

Hyperglycemia (high blood sugar): Hyperglycemia happens when you have too much sugar in your blood. Usually, it means there is not enough insulin to break down the food you eat into energy your body can use. Hyperglycemia can be caused by a fever, an infection, stress, eating more than you should, taking less insulin than prescribed, or it can mean your diabetes is getting worse.

High blood sugar can be mild or severe. High blood sugar can progress to diabetic ketoacidosis (DKA) or very high glucose levels (hyperosmolar coma) and result in unconsciousness and death.

Although diabetic ketoacidosis occurs most often in patients with type 1 diabetes, it can also happen in patients with type 2 diabetes who become very sick. Because some patients get few symptoms of hyperglycemia, it is important to check your blood sugar/urine sugar and ketones regularly.

Symptoms of high blood sugar include:

  • confusion or drowsiness
  • increased thirst
  • decreased appetite, nausea, or vomiting
  • rapid heart rate
  • increased urination and dehydration (too little fluid in your body).

Symptoms of DKA also include:

  • fruity smelling breath
  • fast, deep breathing
  • stomach area pain

Severe or continuing high blood sugar or DKA needs evaluation and treatment right away by your doctor. Do not use insulin glargine to treat diabetic ketoacidosis.

Serious allergic reactions: Sometimes severe, life-threatening allergic reactions can happen with insulin. If you think you are having a severe allergic reaction, get medical help right away. 

Signs of insulin allergy include:

  • rash all over your body
  • shortness of breath
  • wheezing (trouble breathing)
  • fast pulse
  • sweating
  • low blood pressure.

Reactions at the injection site: Injecting insulin can cause the following reactions on the skin at the injection site:

  • little depression in the skin (lipoatrophy)
  • skin thickening (lipohypertrophy)
  • red, swelling, itchy skin (injection site reaction).

You can reduce the chance of getting an injection site reaction if you change (rotate) the injection site each time. An injection site reaction should clear up in a few days or a few weeks. If injection site reactions do not go away or keep happening, call your doctor.

Insulin Glargine Interactions

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins and herbal supplements. Insulin glargine and other medicines may affect each other. Always check with your doctor before starting or stopping any medicines. Especially tell your doctor if you take:

  • oral medicines for diabetes
  • alcohol
  • angiotensin-converting enzyme (ACE) inhibitors such as benazepril (Lotensin), captopril (Capoten), enalapril (Vasotec), fosinopril (Monopril), lisinopril (Prinivil, Zestril), moexipril (Univasc), perindopril (Aceon), quinapril (Accupril), ramipril (Altace), and trandolapril (Mavik)
  • angiotensin receptor II blockers such as azilsartan (Edarbi), candesartan (Atacand), irbesartan (Avapro), losartan (Cozaar), olmesartan (Benicar), telmisartan (Micardis, Twynsta), valsartan (Diovan)
  • beta-blockers such as atenolol (Tenormin), labetalol (Normodyne), metoprolol (Lopressor, Toprol XL), nadolol (Corgard), and propranolol (Inderal)
  • certain cholesterol-lowering medications such as fenofibrate (Antara, Lofibra, TriCor, Triglide), gemfibrozil (Lopid), and niacin (Niacor, Niaspan, in Advicor)
  • clonidine (Catapres, Catapres-TTS, in Clorpres)
  • danazol; disopyramide (Norpace)
  • disopyramide (Norpace)
  • diuretics ('water pills')
  • fibrates such as gemfibrozil (Lopid) and  fenofibrate (TriCor)
  • fluoxetine (Prozac, Sarafem, in Symbyax)
  • glucagon
  • guanethidine (Ismelin)
  • hormone replacement therapy
  • isoniazid (INH, Nydrazid)
  • lithium (Eskalith, Lithobid)
  • medications for asthma and colds
  • medications for mental illness and nausea
  • monoamine oxidase (MAO) inhibitors, including isocarboxazid (Marplan), phenelzine (Nardil), selegiline (Eldepryl) and tranylcypromine (Parnate)
  • niacin
  • octreotide (Sandostatin)
  • oral contraceptives (birth control pills)
  • oral steroids such as dexamethasone (Decadron, Dexone), methylprednisolone (Medrol), and prednisone (Deltasone)
  • pentamidine (NebuPent, Pentam)
  • pentoxifylline (Trental)
  • phenothiazines such as chlorpromazine (Thorazine), thioridazine (Mellaril), fluphenazine (Prolixin), perphenazine (Triavil), prochlorperazine (Compazine), and trifluoperazine (Stelazine)
  • pramlintide (Symlin)
  • propoxyphene (Darvon)
  • reserpine 
  • guanethidine
  • salicylate pain relievers such as aspirin, choline magnesium trisalicylate (Tricosal, Trilisate), choline salicylate (Arthropan), diflunisal (Dolobid), magnesium salicylate (Doan's, others), and salsalate (Argesic, Disalcid, Salgesic)
  • somatropin (Nutropin, Serostim, others)
  • sulfa antibiotics
  • sulfinpyrazone (Anturane)
  • sympathomimetic agents such as albuterol, epinephrine, and terbutaline
  • thyroid medications
  • This is not a complete list of insulin glargine drug interactions. Ask your doctor or pharmacist for more information.

Insulin Glargine Precautions

Serious side effects have been reported with insulin glargine, including:

  • high blood sugars with changes in insulin regimen. Tell your healthcare provider right away if you have some or all of the following symptoms of high blood sugar:
    • excessive thirst
    • excessive urination
    • increased urination at night
    • blurry vision
    • sores that won’t heal
    • fatigue
    • difficulty concentrating
    • frequent urination
    • headaches
    • high blood glucose
    • high levels of sugar in the urine
    • increased fatigue
    • increased thirst
    • weight loss
  • low blood sugar. Tell your healthcare provider right away if you have some or all of the following symptoms of low blood sugar:
    • shakiness
    • nervousness or anxiety
    • sweating, chills and clamminess
    • irritability or impatience
    • confusion, including delirium
    • rapid/fast heartbeat
    • lightheadedness or dizziness
    • hunger and nausea
    • sleepiness
    • blurred/impaired vision
    • tingling or numbness in the lips or tongue
    • headaches
    • weakness or fatigue
    • anger, stubbornness, or sadness
    • lack of coordination
    • nightmares or crying out during sleep
    • seizures
    • unconsciousness
  • medication errors. Take extra precautions against mixing up insulin glargine with other insulin products.
  • allergic reaction. Tell your healthcare provider right away if you have some or all of the following symptoms of an allergic reaction:
  • low potassium in the blood. Tell your healthcare provider right away if you have some or all of the following symptoms of low potassium:
    • constipation
    • feeling of skipped heartbeats or palpitations
    • fatigue
    • muscle damage
    • muscle weakness or spasms
    • tingling or numbness
  • fluid retention and heart failure when taken with PPAR-gamma Agonists. Tell your healthcare provider right away if you have some or all of the following symptoms of fluid retention or heart failure:
    • swollen ankles, legs, abdomen and weight gain.
    • increased need to urinate during the night.
    • loss of appetite or nausea
    • shortness of breath with exercise
    • difficulty breathing at rest or when lying flat in bed
    • dizziness, fatigue, and weakness
    • rapid or irregular heartbeats

Do not use insulin glargine if you are allergic to any of its ingredients. Check with your doctor if you are not sure.

Only use insulin glargine that is clear and colorless.

Accidental mix-ups between insulin products can happen. Make sure you check insulin levels before injection. Your dose of one insulin may be different from another insulin you have taken.

Especially in the case of the brand, Toujeo. This brand of insulin contains 3 times as much insulin in 1 mL as standard insulin. 

Do not change the insulin you are using without talking to your doctor. Any change of insulin should be made cautiously and only under medical supervision. Illness, stress, changes in diet or exercise, and other medical conditions may affect your insulin glargine dosage.

Do not dilute or mix insulin glargine with any other insulin or solution. It will not work as intended and you may lose blood sugar control, which could be serious.

Do not use insulin glargine in insulin pumps. Never inject insulin glargine into a vein or a muscle. It must always be injected just under the skin (subcutaneously).

Do not ever share insulin pens with others. There is a risk for transmission of diseases transmitted through blood when pens are shared. 

You must test your blood sugar levels while using an insulin, such as insulin glargine. Your doctor will tell you how often you should test your blood sugar level, and what to do if it is high or low.

Do not use insulin glargine if you: 

  • are having an episode of low blood sugar
  • have an allergy to insulin glargine or to any of its ingredients

While using insulin glargine do not: 

  • drive or operate heavy machinery, until you know how insulin glargine affects you.
  • drink alcohol or use over-the-counter medicines that contain alcohol.

Insulin Glargine Food Interactions

Follow dietary (food) recommendations made by your doctor and dietitian which should include a healthy diet. Skipping meals should be avoided as this can cause problems maintaining blood sugar control. There are no specific foods to avoid while using insulin glargine.

Inform MD

Tell your doctor if you are allergic to insulin glargine or any other medicines.

Before starting insulin glargine, tell your doctor about all your medical conditions including if you:

  • have liver or kidney disease
  • take any other medicines, especially ones commonly called TZDs (thiazolidinediones).
  • have heart failure or other heart problems. If you have heart failure, it may get worse while you take TZDs with insulin glargine.
  • are pregnant or breastfeeding

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements.

Before you start using insulin glargine, talk to your healthcare provider about low blood sugar and how to manage it.

Insulin Glargine and Pregnancy

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

Insulin glargine falls into category C. In animal studies, pregnant animals were given insulin glargine, and some babies had problems.

It is very important to maintain control of your blood sugar levels during pregnancy. Your doctor will decide which insulin is best for you during your pregnancy.

Insulin Glargine and Lactation

Tell your doctor if you are breastfeeding or plan to breastfeed. It is not known whether insulin glargine passes into your milk. Many medicines, including insulin, pass into human milk and could affect your baby. Talk to your doctor about the best way to feed your baby.

Insulin Glargine Usage

Follow the instructions given by your doctor about the type or types of insulin you are using.

Do not make any changes to your insulin unless you have talked to your doctor. Your insulin needs may change because of illness, stress, other medicines, or changes in diet or activity level. Talk to your doctor about how to adjust your insulin dose.

  • You may use insulin glargine at any time during the day but you must take it at the same time every day.
  • Only use insulin glargine that is clear and colorless. If your insulin glargine is cloudy or slightly colored, return it to your pharmacy for a replacement.
  • Follow your doctor's instructions for testing your blood sugar.
  • Inject insulin glargine under your skin (subcutaneously) in your upper arm, abdomen (stomach area), or thigh (upper leg). Never inject it into a vein or muscle.
  • Change (rotate) injection sites within the same body area.

Insulin glargine 10 mL vial (U-100):

  • The syringe must be new and must not contain any other medicine.
  • Do not mix insulin glargine with any other type of insulin.

Follow these steps to draw insulin into syringe:

1. Wash your hands with soap and water or with alcohol.

2. Check the insulin to make sure it is clear and colorless. Do not use the insulin after the expiration date stamped on the label, if it is colored or cloudy, or if you see particles in the solution.

3. If you are using a new vial, remove the protective cap. Do not remove the stopper.

4. Wipe the top of the vial with an alcohol swab. You do not have to shake the vial of insulin glargine before use.

5. Use a new needle and a U-100 syringe every time you give an injection. Use disposable syringes and needles only once. Throw them away properly. Never share needles and syringes.

6. Draw air into the syringe equal to your insulin dose. Put the needle through the rubber top of the vial and push the plunger to inject the air into the vial.

7. Leave the syringe in the vial and turn both upside down. Hold the syringe and vial firmly in one hand.

8. Make sure the tip of the needle is in the insulin. With your free hand, pull the plunger to withdraw the correct dose into the syringe.

9. Before you take the needle out of the vial, check the syringe for air bubbles. If bubbles are in the syringe, hold the syringe straight up and tap the side of the syringe until the bubbles float to the top. Push the bubbles out with the plunger and draw insulin back in until you have the correct dose.

10. Remove the needle from the vial. Do not let the needle touch anything. You are now ready to inject. Inject insulin glargine under your skin. Take insulin glargine as prescribed by your doctor.

Follow these steps to inject insulin glargine:

  1. Decide on an injection area - either upper arm, thigh or abdomen. Injection sites within an injection area must be different from one injection to the next.
  2. Use alcohol or soap and water to clean the injection site. The injection site should be dry before you inject.
  3. Pinch the skin. Stick the needle in the way your healthcare provider showed you. Release the skin.
  4. Slowly push in the plunger of the syringe all the way, making sure you have injected all the insulin. Leave the needle in the skin for about 10 seconds.
  5. Pull the needle straight out and gently press on the spot where you injected yourself for several seconds. Do not rub the area.
  6. Follow your healthcare providers instructions for throwing away the used needle and syringe. Do not recap the used needle. Used needle and syringe should be placed in sharps containers (such as red biohazard containers), hard plastic containers (such as detergent bottles), or metal containers (such as an empty coffee can). Such containers should be sealed and disposed of properly.

Insulin Pens: 

  • KwikPen
  • SoloStar and Max SoloStar:

It is important to read, understand, and follow the step-by-step instructions before using the disposable insulin pen. Failure to follow the instructions may result in getting too much or too little insulin.

Make sure to check insulin levels before injection. Toujeo contains 3 times as much insulin in 1 mL as standard insulin. 

Insulin Glargine Dosage

Use insulin glargine exactly as prescribed by your doctor. Follow the directions on your prescription label carefully. 

The dose of insulin glargine must be individualized based on several factors including your total daily insulin requirement, your medical conditions, other insulin doses you are receiving, other medicines you are taking, and how your body responds to insulin glargine.

Type 1 diabetes: The dose will be based on total daily insulin requirement and must be used along with a rapid-acting or short-acting insulin.

Type 2 diabetes: The recommended starting dose is 0.2 units/kg once daily. The dose will be adjusted based on blood sugar level reducing response. 

Insulin Glargine Overdose

If you have taken too much insulin glargine, call your local Poison Control Center or seek emergency medical attention right away.

Overdose can occur if you use too much insulin glargine or if you use the right amount of insulin glargine but eat less than usual or exercise more than usual. Insulin glargine overdose can cause low blood sugar. If you have symptoms of low blood sugar, follow your doctor's instructions for what you should do. 

Early symptoms of low blood sugar can include:

  • dizziness
  • shakiness
  • cold sweats
  • blurry vision
  • extreme hunger

More severe symptoms of low blood sugar can include:

  • irritability
  • loss of coordination
  • difficulty speaking
  • confusion
  • seizures
  • loss of consciousness
  • coma
  • loss of life

Other Requirements

Unopened vial or pen: Store new (unopened) insulin glargine vials or pens in a refrigerator (not the freezer) between 36°F to 46°F (2°C to 8°C). Do not freeze insulin glargine. Keep insulin glargine out of direct heat and light. If a vial or pen has been frozen or overheated, throw it away.

Open (In-Use) vial or pen: Once a vial or pen is opened, you can keep it in a refrigerator or at room temperature (below 86°F [30°C]) but away from direct heat and light. Opened vials or pens that are either kept in a refrigerator or at room temperature should be discarded 28 days after the first use even if it still contains insulin glargine. Do not leave your insulin glargine in a car on a summer day.

Do not use insulin glargine after the expiration date. 

Keep this and all medicines out of the reach of children.