Insulin is a naturally occurring hormone made by the pancreas that helps our body use or store the glucose (sugar) it gets from food. For people with diabetes, either the pancreas does not make enough insulin to meet the body's requirements, or the body cannot properly use the insulin that is made. As a result, glucose cannot be used or stored properly and accumulates in the bloodstream. Insulin injected under the skin helps to lower blood glucose levels.

There are many different types of insulin and they are absorbed at different rates and work for varying periods of time. Insulin glargine is an extended, long-acting insulin. It takes about 6 hours to get the full blood-glucose-lowering effect of a dose of this medication, and it stops working after 24 to 36 hours. After injection, insulin glargine is released slowly and constantly into the bloodstream.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop using this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

Your dose of insulin should be injected subcutaneously (under the skin) exactly as instructed by your doctor or diabetes educator. Do not inject insulin glargine into the vein and do not use insulin glargine in insulin infusion pumps. The dose of insulin is measured in international units (IU). Each 1 mL of insulin contains 300 IU. Insulin glargine is injected under the skin once daily.

If you have been using 100 units per mL insulin glargine, you may need to adjust the dose of this medication. Your doctor or diabetes educator can help you with this. In addition to insulin glargine, doses of a fast-acting insulin are usually used to control the impact of food intake on blood sugar levels during the day. There are many variations of insulin dosing.

This medication is available in two sizes of pre-filled disposable pens for injection. Toujeo SoloSTAR delivers insulin in increments of 1 unit, while Toujeo DoubleSTAR delivers insulin in increments of 2 units.

Insulin glargine should be clear and colourless. Do not use the insulin if you notice anything unusual in the appearance of the solution, such as cloudiness, discoloration, or clumping. It is not necessary to shake or rotate the vial before use.

It should not be mixed with other insulins.

Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are using the medication without consulting your doctor.

It is very important that you use this medication exactly as prescribed by your doctor. The timing of insulin with respect to your meals is crucial for keeping blood glucose under control and preventing unwanted side effects. If you miss a dose, check your blood glucose more often, and if you become hyperglycemic, treat the hyperglycemia as you have been taught by your doctor or diabetes educator.

Keep unopened insulin pens in the refrigerator until needed. They may be used until the expiry date on the label. Never allow insulin to freeze. An open, pre-filled pen may be kept at room temperature and must be discarded 42 days after it is first used. Do not expose insulin to extremely hot temperatures or to sunlight. Keep insulin out of the reach of children.

Each disposable prefilled pen contains 900 units of insulin glargine (300 units per mL). Nonmedicinal ingredients: zinc chloride, m-cresol, glycerol, hydrochloric acid and sodium hydroxide for pH adjustment, and water for injection.

Do not use this medication if you:

• are allergic to insulin or to any of the ingredients of the medication
• have low blood sugar (hypoglycemia)

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• increased weight
• redness, itching, or swelling at the site of the injection

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• signs of high blood glucose:
  • confusion
  • signs of dehydration (e.g., decreased urine, dry skin, dry and sticky mouth, sleepiness, dizziness, headache, thirst, confusion)
  • drowsiness
  • flushed face
  • fruity breath odour
  • increased thirst
  • increased need to urinate
  • weight loss
• signs of low blood glucose:
  • anxiety
  • blurred vision
  • confusion
  • difficulty concentrating
  • difficulty speaking
  • dizziness
  • drowsiness
  • fast heartbeat
  • headache
  • hunger
  • nausea
  • nervousness
  • numbness or tingling of the lips, fingers, or tongue
  • sweating
  • tiredness
  • trembling
  • weakness
• swelling around the ankles or calves (fluid build-up in the body)
• vision changes

Stop taking the medication and seek immediate medical attention if any of the following occur:

• rash or blisters all over the body
• seizures
• symptoms of a serious allergic reaction (e.g., swelling of the face or throat, difficulty breathing, wheezing, or itchy skin rash)
• unconsciousness

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Allergic reactions: If you notice signs of a serious allergic reaction (swelling of the face or throat, difficulty breathing, wheezing, or itchy skin rash), stop using the medication and seek immediate medical attention.

Appearance of insulin: The contents of the vial of insulin glargine should be clear and colourless. Do not use this medication if you notice anything unusual about its appearance, such as cloudiness, discoloration, or clumping.

Blood glucose monitoring: It is important for anyone using insulin to monitor their blood glucose levels regularly, as recommended by their doctor or diabetes educator. It is especially important to test blood glucose more often when your insulin dose or schedule changes, or when you are ill or under stress. If blood tests consistently show high or low blood glucose levels, contact your doctor or diabetes educator.

Changes at injection site: Fatty tissue under the skin at the injection site may shrink or thicken if you inject yourself too often at the same site. To help avoid this effect, change the site with each injection. Talk to your doctor or diabetes educator if you notice your skin pitting or thickening at the injection site.

Changes in insulin requirements: Many things can affect blood glucose levels and insulin requirements. These include:

• certain medical conditions (e.g., infections, thyroid conditions, or kidney or liver disease)
• certain medications that increase or decrease blood glucose levels
• diet
• exercise
• illness
• injury
• stress
• surgery
• travelling over time zones

It is important your doctor know your current health situation and any changes that may affect the amount of insulin you need. Blood glucose should be monitored regularly as recommended by your doctor or diabetes educator.

Diabetes identification: It is important to either wear a bracelet (or necklace) or carry a card indicating you have diabetes and are taking insulin.

Family and friends: Educate your family and friends about the signs and symptoms of hypoglycemia (low blood glucose). Keep a glucagon kit available and instruct them on its proper use in case you experience severe low blood glucose and you lose consciousness.

High blood glucose (hyperglycemia): Hyperglycemia may occur if your insulin dose is too low or you miss a dose of insulin. Symptoms of hyperglycemia generally build up over hours or days. If you experience symptoms of hyperglycemia, such as increased need to urinate, nausea, vomiting, drowsiness, dry mouth, flushed dry skin, loss of appetite, and a fruity odour to your breath, contact your doctor or diabetes educator.

If hyperglycemia is allowed to continue, a condition known as diabetic ketoacidosis may occur. In this condition, your body starts to use body fat as fuel, eventually leading to a large concentration of acid in the blood stream. This can result in unconsciousness, coma, or death. To prevent this from occurring, you may need to have your insulin dose adjusted.

Kidney function: Kidney disease or reduced kidney function may change the amount of insulin needed by the body. If you have kidney problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. Your doctor may want to test your kidney function regularly with blood tests while you are taking this medication.

Liver function: Liver disease or reduced liver function may change the amount of insulin needed by the body. If you have liver problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. Your doctor may want to test your liver function regularly with blood tests while you are taking this medication.

Low blood glucose (hypoglycemia): Hypoglycemia may occur if too much insulin is used, if meals are missed, or if you exercise more than usual. Symptoms of mild-to-moderate hypoglycemia may occur suddenly and can include cold sweat, nervousness or shakiness, fast heartbeat, headache, hunger, confusion, lightheadedness, weakness, and numbness or tingling (tongue, lips, or fingers). Mild-to-moderate hypoglycemia may be treated by eating foods or drinks that contain sugar. People taking insulin should always carry a quick source of sugar, such as hard candies, glucose tablets, juice, or regular soft drinks (not diet soft drinks).

Signs of severe hypoglycemia can include disorientation, loss of consciousness, and seizures. People who are unable to take sugar by mouth or who are unconscious may require an injection of glucagon or treatment with intravenous (into the vein) glucose.

Pregnancy: It is essential to maintain good blood glucose control throughout pregnancy. Insulin requirements usually decrease during the first trimester and increase during the second and third trimesters. Therefore, contact your doctor if you are pregnant or are thinking about pregnancy.

Breast-feeding: It is not known if insulin glargine passes into breast milk. If you are breast-feeding and are using this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding. Breast-feeding mothers may require adjustments in insulin dose or diet.

Children: The safety and effectiveness of using this medication have not been established for children under 6 years of age with type 1 diabetes and children under 18 years of age with type 2 diabetes.

There may be an interaction between insulin glargine and any of the following:

• alcohol
• androgens (e.g., testosterone)
• atypical antipsychotics (e.g., clozapine, olanzapine, quetiapine, risperidone)
• beta-blockers (e.g., atenolol, metoprolol, pindolol, propranolol, sotalol)
• birth control pills
• clarithromycin
• corticosteroids (e.g., prednisone, prednisolone)
• danazol
• decongestants (e.g., pseudoephedrine)
• other diabetes medications (e.g., canagliflozin, dulaglutide, glyburide, insulin, liraglutide, metformin, rosiglitazone)
• disopyramide
• certain diuretics (e.g., furosemide, hydrochlorothiazide)
• epinephrine
• estrogens (e.g., conjugated estrogen, estradiol, ethinyl estradiol)
• glucagon
• growth hormone
• hepatitis C antivirals (e.g., ledipasvir, sofosbuvir)
• HIV protease inhibitors (e.g., atazanavir, ritonavir, saquinavir)
• certain kinase inhibitors (e.g., dabrafenib, nilotinib, sunitinib)
• monoamine oxidase inhibitors (MAOIs; e.g., moclobemide, phenelzine, rasagiline, selegiline, tranylcypromine)
• niacin
• octreotide
• pasireotide
• pegvisomant
• progestins (e.g., dienogest, levonorgestrel, medroxyprogesterone, norethindrone)
• quinine
• quinolone antibiotics (e.g., ciprofloxacin, norfloxacin, ofloxacin)
• salicylates (e.g., ASA)
• selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, fluoxetine, paroxetine, sertraline)
• sulfa antibiotics (e.g., sulfamethoxazole, sulfadiazine)
• tacrolimus
• thyroid replacement therapy (if beginning or changing dose)
• tramadol
• vorinostat

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.