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Toujeo Solostar: 7 things you should know

Medically reviewed by Carmen Fookes, BPharm. Last updated on Oct 1, 2021.

1. How it works

  • Toujeo Solostar is a brand name for a type of long-acting insulin prefilled pen that contains insulin glargine at a concentration of 300 units/mL.
  • Insulin glargine is a biosynthetic human insulin analog of rDNA origin that has been made using genetic engineering technology. Although it resembles human insulin in most of its structure, the amino acid arginine in position A21 has been replaced by glycine and two arginines have been added to the C-terminus of the B-chain.
  • Toujeo Solostar was formulated to be convenient to use and have a low insulin solubility at neutral pH which means it forms microprecipitates when injected under the skin (subcutaneously), which allows the insulin to be released slowly from the injection site. Toujeo Solostar is more concentrated than other insulin glargine, such as Lantus Solostar.
  • The primary activity of insulin, which includes Toujeo Solostar, is to allow cells throughout the body to uptake glucose (sugar) and convert it into a form that can be used by these cells for energy.

2. Upsides

  • May be used for the treatment of type 1 diabetes in adults and children over the age of six who require a long-acting insulin for their diabetes control.
  • Toujeo Solostar is a long-acting insulin that lasts up to 36 hours. Only needs to be given once a day; however, twice-daily administration may lessen the risk of hypoglycemia.
  • May be used to control blood sugar levels in adults with type 2 diabetes who require a long-acting insulin when other medications are no longer effective at improving blood sugar levels.
  • Toujeo Solostar is a prefilled pen that is for single patient-use. This 1.5mL pen contains 450 units of insulin (at a concentration of 300U/mL. Units can be increased by 1 unit at a time by moving the dial on the pen. The maximum dosage that can be given with one injection is 80 units. Toujeo Max Solostar contains 3mL of insulin (at a concentration of 300U/mL).
  • Concentrated forms of insulin have been shown to last longer in the body with less variability in blood levels over time. This translates to a lower risk of hypoglycemia, especially at night.
  • Toujeo Solostar does not pass into breast milk and will not affect a nursing infant.

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

  • Low blood sugar levels (hypoglycemia) are the most common side effect of Toujeo Solostar. The risk of hypoglycemia increases with tighter blood sugar controls, changes in meal patterns, with certain coadministered medications, and changes in physical activity levels. People with liver or kidney disease may be at a higher risk of hypoglycemia.
  • All insulins can cause potassium levels to go low (this is called hypokalemia). Insulin may also cause sodium retention, weight gain, fluid retention and swelling, itching, redness, or lumps around the injection site. There is a risk of infection if a Toujeo‚ÄčSolostar pen is shared.
  • The dosage of Toujeo‚ÄčSolostar may need to be reduced in liver or kidney disease. Blood glucose levels should be carefully monitored in people with these conditions.
  • Seniors may be more susceptible to the side effects of long-acting insulins, such as insulin glargine. The dosage of Toujeo Solostar in elderly people should be conservative.
  • Toujeo Solostar must be given by subcutaneous (under the skin) injection. It should not be given by IV, IM, or via an infusion pump.
  • Toujeo Solostar is not suitable for the treatment of diabetic ketoacidosis. Short-acting insulins should be used to treat this condition.
  • Seniors may have more difficulty using the Toujeo Solostar pen due to poor vision or dexterity problems, making it difficult to dial the correct dosage or inject the insulin under their skin.
  • Studies that investigated the use of insulin, such as Toujeo Solostar during pregnancy, have not identified a clear association with insulin and adverse developmental outcomes. There are risks to the mother and fetus associated with poorly controlled diabetes in pregnancy such as diabetic ketoacidosis, preeclampsia, spontaneous abortions, preterm delivery, and delivery complications. The risk of major birth defects is 6% to 10% in women with pregestational diabetes with an HbA1c >7 and has been reported to be as high as 20% to 25% in women with an HbA1c >10. In general, the benefits of using insulin during pregnancy outweigh the risks.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

  • Toujeo Solostar contains insulin glargine in a prefilled pen at a higher concentration (300 units per mL) than other forms of insulin glargine, such as Lantus Solostar, and one pen contains 450 units in total. An easy-to-use dial on the top of the pen allows the administration of an exact dosage tailored to an individual patient's requirements. The pen may be kept out of the refrigerator for 56 days when in use.

5. Tips

  • Tell your doctor if you have ever had an allergic reaction to any type of insulin before you start using Toujeo Solostar.
  • Children are especially sensitive to the effects of insulin, particularly around puberty.
  • There are so many different types of insulin that medication errors are common. Always check the label on your insulin to make sure it is the brand you have been prescribed and it is the correct strength. Talk to your doctor or pharmacist if you are unsure. Always make sure you dial up the correct dose of Toujeo Solostar for you.
  • The dosage of Toujeo Solostar needs to be individualized. This may take time, so ensure you monitor your blood sugars regularly when titrating the dosage of Toujeo Solostar, and tell your doctor the results.
  • Never share your Toujeo Solostar pen with other people. Store your pens as recommended on the label.
  • Inject your insulin exactly as directed by your doctor. Take all other medications as prescribed.
  • Your insulin requirements may change if you become unwell, develop an infection, or have other medical conditions. Surgery, injury, mental stress, your diet, and how much exercise you do can also affect how much insulin you need. Puberty, pregnancy, and menopause can also affect insulin requirements. Conditions that delay food absorption or stomach emptying can slow down the time it takes to break down and absorb food which can change how much insulin you need.
  • Be alert for symptoms of hypoglycemia which may include a headache, sweating, trembling, anxiety, confusion, irritability, rapid breathing, or a fast heartbeat. People with hypoglycemia may also faint and severe hypoglycemia that is left untreated may be fatal. Tell your family, friends, and caregivers to give you some fast-acting sugar (such as some jellybeans, fruit juice, or honey) if they notice you have symptoms of hypoglycemia and then follow it up with a more substantial meal or glucagon injection if you are unconscious.
  • Insulin is easily broken down by extreme temperatures, which means you need to be careful if you live in a part of the U.S. that gets very hot in summer, or very cold in winter.
  • Toujeo Solostar that has been opened may be kept at room temperature (59 to 77 degrees Fahrenheit [15-25 degrees Celcius]) for up to 56 days, much longer than most other insulins that can only be left unrefrigerated for up to 28 days.
  • If you are going out in the sun, always use an insulated bag protected by a cool pack to ensure your Toujeo Solostar doesn't heat up; but avoid freezing it. During cold weather, keep your Toujeo Solostar close to your skin so your body heat keeps it at a more even temperature. Discard any Toujeo Solostar pens that you think may have inadvertently got too hot or too cold. The expiry date on Toujeo Solostar applies to unopened, refrigerated insulin.
  • If you become pregnant while on Toujeo Solostar, tell your doctor immediately. Controlling diabetes during pregnancy is very important and high blood sugar levels can be detrimental both to you and your developing baby.

6. Response and effectiveness

  • Starts to work within 70 minutes after injection
  • Has no pronounced peak but full blood sugar-lowering effects can take 6 hours to develop after administration
  • Toujeo lasts for up to 36 hours and is usually given once a day, usually in the morning.
  • Even though Toujeo is usually given once a day, some people may experience better blood sugar control if the dose is split and given twice a day (every 12 hours). Those that tend to benefit from twice-daily Toujeo include those experiencing early morning hypoglycemia or persistent hyperglycemia at dinner time. Twice daily Toujeo can also improve HbA1c levels. Some reports have stated the risk of hypoglycemia may be up to 30% less with Toujeo compared to Lantus.
  • Toujeo Solostar is more concentrated than other insulin glargine, such as Lantus Solostar. Toujeo Solostar contains 300 units per mL of insulin glargine, compared with Lantus Solostar that contains 100 units per ml. However, even though Toujeo contains more insulin per volume than Lantus, the pen has been calibrated in a way that the conversion from Lantus to Toujeo and vice versa is still 1:1. This means that if you have been prescribed 22 units of Lantus and you were changed to Toujeo the equivalent dose would still be 22 units of Toujeo.

7. Interactions

Medicines that interact with Toujeo Solostar may either decrease its effect, affect how long it works for, increase side effects, or have less of an effect when taken with Toujeo Solostar. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with Toujeo Solostar include:

  • antibiotics, such as doxycycline and minocycline
  • antidepressants such as SSRIs (eg, fluoxetine, sertraline), monoamine oxidase inhibitors (MAOI) such as selegiline, isocarboxazid, and phenelzine
  • antiepileptics, such as fosphenytoin and phenytoin
  • antipsychotics, such as aripiprazole, chlorpromazine
  • antivirals such as amprenavir, atazanavir, and fosamprenavir
  • aspirin
  • beta-blockers, such as acebutolol, atenolol, or timolol
  • cyclosporine
  • diuretics, such as furosemide, chlorthalidone, or hydrochlorothiazide
  • fluoroquinolone antibiotics, such as ciprofloxacin or norfloxacin
  • gemfibrozil
  • heart medications such as captopril, candesartan, or clonidine
  • hormones, such as estradiol, estrone, and norethindrone
  • lithium
  • niacin
  • pentamidine
  • salmeterol
  • steroids, such as cortisone, dexamethasone, fludrocortisone, or prednisone
  • sucralfate
  • tacrolimus or pimecrolimus
  • topiramate
  • turmeric
  • aloe vera
  • other insulins
  • other medications that affect blood sugar levels or are used for diabetes, such as chlorpropamide, glimepiride, or glipizide.

Alcohol may also interact with Toujeo Solostar by blocking the production of glucose by the liver, causing hypoglycemia.

Note that this list is not all-inclusive and includes only common medications that may interact with Toujeo Solostar. You should refer to the prescribing information for Toujeo Solostar for a complete list of interactions.


Toujeo (insulin glargine) [Package Insert]. Updated 12/2020. Sanofi-Aventis U.S. LLC

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Toujeo Solostar only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Copyright 1996-2022 Revision date: September 30, 2021.