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

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Pharmacist Lindsay Morrison, PharmD overviews the uses and common side effects of Lantus
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Pharmacist Lindsay Morrison, PharmD overviews the uses and common side effects of Lantus
Pharmacist Trey Robinson, PharmD summarizes the uses, common side effects, and warnings for the Insulin class of medications

Lantus Overview


Lantus is a prescription medication used to treat type 1 and type 2 diabetes. Lantus is a long-acting form of insulin and 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 and is usually used once daily.

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


How was your experience with Lantus?

First, a little about yourself

Tell us about yourself in a few words?

What tips would you provide a friend before taking Lantus?

What are you taking Lantus for?

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

How long have you been taking it?

Choose one
  • Less than a week
  • A couple weeks
  • A month or so
  • A few months
  • A year or so
  • Two years or more

How well did Lantus work for you?

Did you experience many side effects while taking this drug?

How likely would you be to recommend Lantus to a friend?

Lantus Cautionary Labels


Uses of Lantus

Lantus is a prescription medication used to treat people with type 1 and type 2 diabetes for the control of high blood sugar. Lantus 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.



Lantus Drug Class

Lantus is part of the drug class:

Side Effects of Lantus

Lantus can cause hypoglycemia (low blood sugar), hyperglycemia (high blood sugar), allergy, and skin reactions.

Hypoglycemia (low blood sugar): Early warning signs of hypoglycemia 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 hypoglycemia 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 heart beat)
  • sweating
  • tremor (shaking)
  • unsteady gait (walking).

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

Mild to moderate hypoglycemia 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 hypoglycemia.

Severe hypoglycemia may require the help of another person or emergency medical people. A person with hypoglycemia 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 Lantus 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 Lantus than prescribed, or it can mean your diabetes is getting worse.

Hyperglycemia can be mild or severe. Hyperglycemia 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 hyperglycemia 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 (abdominal) pain.

Severe or continuing hyperglycemia or DKA needs evaluation and treatment right away by your doctor. Do not use Lantus to treat diabetic ketoacidosis.

Serious allergic reactions: Some times severe, life-threatening allergic reactions can happen with Lantus. 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 such as Lantus 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.

Lantus Interactions

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins and herbal supplements. Lantus 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
  • pramlintide (Symlin)
  • 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)
  • 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)
  • diuretics ('water pills')
  • fluoxetine (Prozac, Sarafem, in Symbyax)
  • glucagon
  • 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)
  • octreotide (Sandostatin)
  • oral contraceptives (birth control pills)
  • oral steroids such as dexamethasone (Decadron, Dexone), methylprednisolone (Medrol), and prednisone (Deltasone)
  • pentamidine (NebuPent, Pentam)
  • pentoxifylline (Trental)
  • reserpine 
  • 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)
  • thyroid medications

This is not a complete list of Lantus drug interactions. Ask your doctor or pharmacist for more information.

Lantus Precautions

Do not take Lantus if you are allergic to any of its ingredients. Check with your doctor if you are not sure.

Only use Lantus that is clear and colorless.

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

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

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

Lantus 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 Lantus.

Inform MD

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

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

  • have liver or kidney disease
  • are pregnant or breastfeeding

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

Lantus 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.

Lantus falls into category C. In animal studies, pregnant animals were given Lantus, 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.

Lantus and Lactation

Tell your doctor if you are breastfeeding or plan to breastfeed. It is not known whether Lantus 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.

Lantus Usage

Follow the instructions given by your doctor about the type or types of insulin you are using. Do not make any changes with 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 take Lantus at any time during the day but you must take it at the same time every day.
  • Only use Lantus that is clear and colorless. If your Lantus is cloudy or slightly colored, return it to your pharmacy for a replacement.
  • Follow your doctor's instructions for testing your blood sugar.
  • Inject Lantus 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.

Lantus  10 mL vial (U-100):

  • The syringe must be new and must not contain any other medicine.
  • Do not mix Lantus 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 Lantus 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 Lantus under your skin. Take Lantus as prescribed by your doctor.

Follow these steps to inject Lantus:

  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.

Lantus SoloStar

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

Lantus Dosage

Take Lantus exactly as prescribed by your doctor. Follow the directions on your prescription label carefully. The dose of Lantus must be individualized based on several factors including your medical conditions, other insulin doses you are receiving, other medicines you are taking, and how your body responds to Lantus.

In people with type 1 diabetes, Lantus must be used along with a short-acting insulin.

The recommended starting Lantus dose for people with type 2 diabetes is 10 units (U) once daily, if no other insulin is being used.


Lantus Overdose

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

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

Early symptoms of hypoglycemia can include:

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

More severe symptoms of hypoglycemia can include:

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

Other Requirements

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

Open (In-Use) vial: Once a vial 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 vial, either kept in a refrigerator or at room temperature, should be discarded 28 days after the first use even if it still contains Lantus. Do not leave your insulin in a car on a summer day.